feat: encrypt private keys saved on disk and in database (#682)

Co-authored-by: Kyle Mendell <kmendell@ofkm.us>

backend/internal/bootstrap/services_bootstrap.go

@@ -38,7 +38,7 @@ func initServices(ctx context.Context, db *gorm.DB, httpClient *http.Client) (sv
 
 	svc.geoLiteService = service.NewGeoLiteService(httpClient)
 	svc.auditLogService = service.NewAuditLogService(db, svc.appConfigService, svc.emailService, svc.geoLiteService)
-	svc.jwtService = service.NewJwtService(svc.appConfigService)
+	svc.jwtService = service.NewJwtService(db, svc.appConfigService)
 	svc.userService = service.NewUserService(db, svc.jwtService, svc.auditLogService, svc.emailService, svc.appConfigService)
 	svc.customClaimService = service.NewCustomClaimService(db)
 

backend/internal/common/env_config.go

@@ -1,6 +1,8 @@
 package common
 
 import (
+	"errors"
+	"fmt"
 	"log"
 	"net/url"
 
@@ -18,9 +20,10 @@ const (
 )
 
 const (
-	DbProviderSqlite      DbProvider = "sqlite"
+	DbProviderSqlite        DbProvider = "sqlite"
-	DbProviderPostgres    DbProvider = "postgres"
+	DbProviderPostgres      DbProvider = "postgres"
-	MaxMindGeoLiteCityUrl string     = "https://download.maxmind.com/app/geoip_download?edition_id=GeoLite2-City&license_key=%s&suffix=tar.gz"
+	MaxMindGeoLiteCityUrl   string     = "https://download.maxmind.com/app/geoip_download?edition_id=GeoLite2-City&license_key=%s&suffix=tar.gz"
+	defaultSqliteConnString string     = "file:data/pocket-id.db?_pragma=journal_mode(WAL)&_pragma=busy_timeout(2500)&_txlock=immediate"
 )
 
 type EnvConfigSchema struct {
@@ -30,6 +33,9 @@ type EnvConfigSchema struct {
 	DbConnectionString string     `env:"DB_CONNECTION_STRING"`
 	UploadPath         string     `env:"UPLOAD_PATH"`
 	KeysPath           string     `env:"KEYS_PATH"`
+	KeysStorage        string     `env:"KEYS_STORAGE"`
+	EncryptionKey      string     `env:"ENCRYPTION_KEY"`
+	EncryptionKeyFile  string     `env:"ENCRYPTION_KEY_FILE"`
 	Port               string     `env:"PORT"`
 	Host               string     `env:"HOST"`
 	UnixSocket         string     `env:"UNIX_SOCKET"`
@@ -45,52 +51,83 @@ type EnvConfigSchema struct {
 	AnalyticsDisabled  bool       `env:"ANALYTICS_DISABLED"`
 }
 
-var EnvConfig = &EnvConfigSchema{
+var EnvConfig = defaultConfig()
-	AppEnv:             "production",
-	DbProvider:         "sqlite",
-	DbConnectionString: "file:data/pocket-id.db?_pragma=journal_mode(WAL)&_pragma=busy_timeout(2500)&_txlock=immediate",
-	UploadPath:         "data/uploads",
-	KeysPath:           "data/keys",
-	AppURL:             "http://localhost:1411",
-	Port:               "1411",
-	Host:               "0.0.0.0",
-	UnixSocket:         "",
-	UnixSocketMode:     "",
-	MaxMindLicenseKey:  "",
-	GeoLiteDBPath:      "data/GeoLite2-City.mmdb",
-	GeoLiteDBUrl:       MaxMindGeoLiteCityUrl,
-	LocalIPv6Ranges:    "",
-	UiConfigDisabled:   false,
-	MetricsEnabled:     false,
-	TracingEnabled:     false,
-	TrustProxy:         false,
-	AnalyticsDisabled:  false,
-}
 
 func init() {
-	if err := env.ParseWithOptions(EnvConfig, env.Options{}); err != nil {
+	err := parseEnvConfig()
-		log.Fatal(err)
+	if err != nil {
+		log.Fatalf("Configuration error: %v", err)
+	}
+}
+
+func defaultConfig() EnvConfigSchema {
+	return EnvConfigSchema{
+		AppEnv:             "production",
+		DbProvider:         "sqlite",
+		DbConnectionString: "",
+		UploadPath:         "data/uploads",
+		KeysPath:           "data/keys",
+		KeysStorage:        "", // "database" or "file"
+		EncryptionKey:      "",
+		AppURL:             "http://localhost:1411",
+		Port:               "1411",
+		Host:               "0.0.0.0",
+		UnixSocket:         "",
+		UnixSocketMode:     "",
+		MaxMindLicenseKey:  "",
+		GeoLiteDBPath:      "data/GeoLite2-City.mmdb",
+		GeoLiteDBUrl:       MaxMindGeoLiteCityUrl,
+		LocalIPv6Ranges:    "",
+		UiConfigDisabled:   false,
+		MetricsEnabled:     false,
+		TracingEnabled:     false,
+		TrustProxy:         false,
+		AnalyticsDisabled:  false,
+	}
+}
+
+func parseEnvConfig() error {
+	err := env.ParseWithOptions(&EnvConfig, env.Options{})
+	if err != nil {
+		return fmt.Errorf("error parsing env config: %w", err)
 	}
 
 	// Validate the environment variables
 	switch EnvConfig.DbProvider {
 	case DbProviderSqlite:
 		if EnvConfig.DbConnectionString == "" {
-			log.Fatal("Missing required env var 'DB_CONNECTION_STRING' for SQLite database")
+			EnvConfig.DbConnectionString = defaultSqliteConnString
 		}
 	case DbProviderPostgres:
 		if EnvConfig.DbConnectionString == "" {
-			log.Fatal("Missing required env var 'DB_CONNECTION_STRING' for Postgres database")
+			return errors.New("missing required env var 'DB_CONNECTION_STRING' for Postgres database")
 		}
 	default:
-		log.Fatal("Invalid DB_PROVIDER value. Must be 'sqlite' or 'postgres'")
+		return errors.New("invalid DB_PROVIDER value. Must be 'sqlite' or 'postgres'")
 	}
 
 	parsedAppUrl, err := url.Parse(EnvConfig.AppURL)
 	if err != nil {
-		log.Fatal("APP_URL is not a valid URL")
+		return errors.New("APP_URL is not a valid URL")
 	}
 	if parsedAppUrl.Path != "" {
-		log.Fatal("APP_URL must not contain a path")
+		return errors.New("APP_URL must not contain a path")
 	}
+
+	switch EnvConfig.KeysStorage {
+	// KeysStorage defaults to "file" if empty
+	case "":
+		EnvConfig.KeysStorage = "file"
+	case "database":
+		// If KeysStorage is "database", a key must be specified
+		if EnvConfig.EncryptionKey == "" && EnvConfig.EncryptionKeyFile == "" {
+			return errors.New("ENCRYPTION_KEY or ENCRYPTION_KEY_FILE must be non-empty when KEYS_STORAGE is database")
+		}
+	case "file":
+		// All good, these are valid values
+	default:
+		return fmt.Errorf("invalid value for KEYS_STORAGE: %s", EnvConfig.KeysStorage)
+	}
+
+	return nil
 }

backend/internal/common/env_config_test.go

@@ -0,0 +1,188 @@
+package common
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestParseEnvConfig(t *testing.T) {
+	// Store original config to restore later
+	originalConfig := EnvConfig
+	t.Cleanup(func() {
+		EnvConfig = originalConfig
+	})
+
+	t.Run("should parse valid SQLite config correctly", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "sqlite")
+		t.Setenv("DB_CONNECTION_STRING", "file:test.db")
+		t.Setenv("APP_URL", "http://localhost:3000")
+
+		err := parseEnvConfig()
+		require.NoError(t, err)
+		assert.Equal(t, DbProviderSqlite, EnvConfig.DbProvider)
+	})
+
+	t.Run("should parse valid Postgres config correctly", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "postgres")
+		t.Setenv("DB_CONNECTION_STRING", "postgres://user:pass@localhost/db")
+		t.Setenv("APP_URL", "https://example.com")
+
+		err := parseEnvConfig()
+		require.NoError(t, err)
+		assert.Equal(t, DbProviderPostgres, EnvConfig.DbProvider)
+	})
+
+	t.Run("should fail with invalid DB_PROVIDER", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "invalid")
+		t.Setenv("DB_CONNECTION_STRING", "test")
+		t.Setenv("APP_URL", "http://localhost:3000")
+
+		err := parseEnvConfig()
+		require.Error(t, err)
+		assert.ErrorContains(t, err, "invalid DB_PROVIDER value")
+	})
+
+	t.Run("should set default SQLite connection string when DB_CONNECTION_STRING is empty", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "sqlite")
+		t.Setenv("DB_CONNECTION_STRING", "") // Explicitly empty
+		t.Setenv("APP_URL", "http://localhost:3000")
+
+		err := parseEnvConfig()
+		require.NoError(t, err)
+		assert.Equal(t, defaultSqliteConnString, EnvConfig.DbConnectionString)
+	})
+
+	t.Run("should fail when Postgres DB_CONNECTION_STRING is missing", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "postgres")
+		t.Setenv("APP_URL", "http://localhost:3000")
+
+		err := parseEnvConfig()
+		require.Error(t, err)
+		assert.ErrorContains(t, err, "missing required env var 'DB_CONNECTION_STRING' for Postgres")
+	})
+
+	t.Run("should fail with invalid APP_URL", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "sqlite")
+		t.Setenv("DB_CONNECTION_STRING", "file:test.db")
+		t.Setenv("APP_URL", "€://not-a-valid-url")
+
+		err := parseEnvConfig()
+		require.Error(t, err)
+		assert.ErrorContains(t, err, "APP_URL is not a valid URL")
+	})
+
+	t.Run("should fail when APP_URL contains path", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "sqlite")
+		t.Setenv("DB_CONNECTION_STRING", "file:test.db")
+		t.Setenv("APP_URL", "http://localhost:3000/path")
+
+		err := parseEnvConfig()
+		require.Error(t, err)
+		assert.ErrorContains(t, err, "APP_URL must not contain a path")
+	})
+
+	t.Run("should default KEYS_STORAGE to 'file' when empty", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "sqlite")
+		t.Setenv("DB_CONNECTION_STRING", "file:test.db")
+		t.Setenv("APP_URL", "http://localhost:3000")
+
+		err := parseEnvConfig()
+		require.NoError(t, err)
+		assert.Equal(t, "file", EnvConfig.KeysStorage)
+	})
+
+	t.Run("should fail when KEYS_STORAGE is 'database' but no encryption key", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "sqlite")
+		t.Setenv("DB_CONNECTION_STRING", "file:test.db")
+		t.Setenv("APP_URL", "http://localhost:3000")
+		t.Setenv("KEYS_STORAGE", "database")
+
+		err := parseEnvConfig()
+		require.Error(t, err)
+		assert.ErrorContains(t, err, "ENCRYPTION_KEY or ENCRYPTION_KEY_FILE must be non-empty")
+	})
+
+	t.Run("should accept valid KEYS_STORAGE values", func(t *testing.T) {
+		validStorageTypes := []string{"file", "database"}
+
+		for _, storage := range validStorageTypes {
+			EnvConfig = defaultConfig()
+			t.Setenv("DB_PROVIDER", "sqlite")
+			t.Setenv("DB_CONNECTION_STRING", "file:test.db")
+			t.Setenv("APP_URL", "http://localhost:3000")
+			t.Setenv("KEYS_STORAGE", storage)
+			if storage == "database" {
+				t.Setenv("ENCRYPTION_KEY", "test-key")
+			}
+
+			err := parseEnvConfig()
+			require.NoError(t, err)
+			assert.Equal(t, storage, EnvConfig.KeysStorage)
+		}
+	})
+
+	t.Run("should fail with invalid KEYS_STORAGE value", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "sqlite")
+		t.Setenv("DB_CONNECTION_STRING", "file:test.db")
+		t.Setenv("APP_URL", "http://localhost:3000")
+		t.Setenv("KEYS_STORAGE", "invalid")
+
+		err := parseEnvConfig()
+		require.Error(t, err)
+		assert.ErrorContains(t, err, "invalid value for KEYS_STORAGE")
+	})
+
+	t.Run("should parse boolean environment variables correctly", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "sqlite")
+		t.Setenv("DB_CONNECTION_STRING", "file:test.db")
+		t.Setenv("APP_URL", "http://localhost:3000")
+		t.Setenv("UI_CONFIG_DISABLED", "true")
+		t.Setenv("METRICS_ENABLED", "true")
+		t.Setenv("TRACING_ENABLED", "false")
+		t.Setenv("TRUST_PROXY", "true")
+		t.Setenv("ANALYTICS_DISABLED", "false")
+
+		err := parseEnvConfig()
+		require.NoError(t, err)
+		assert.True(t, EnvConfig.UiConfigDisabled)
+		assert.True(t, EnvConfig.MetricsEnabled)
+		assert.False(t, EnvConfig.TracingEnabled)
+		assert.True(t, EnvConfig.TrustProxy)
+		assert.False(t, EnvConfig.AnalyticsDisabled)
+	})
+
+	t.Run("should parse string environment variables correctly", func(t *testing.T) {
+		EnvConfig = defaultConfig()
+		t.Setenv("DB_PROVIDER", "postgres")
+		t.Setenv("DB_CONNECTION_STRING", "postgres://test")
+		t.Setenv("APP_URL", "https://prod.example.com")
+		t.Setenv("APP_ENV", "staging")
+		t.Setenv("UPLOAD_PATH", "/custom/uploads")
+		t.Setenv("KEYS_PATH", "/custom/keys")
+		t.Setenv("PORT", "8080")
+		t.Setenv("HOST", "127.0.0.1")
+		t.Setenv("UNIX_SOCKET", "/tmp/app.sock")
+		t.Setenv("MAXMIND_LICENSE_KEY", "test-license")
+		t.Setenv("GEOLITE_DB_PATH", "/custom/geolite.mmdb")
+
+		err := parseEnvConfig()
+		require.NoError(t, err)
+		assert.Equal(t, "staging", EnvConfig.AppEnv)
+		assert.Equal(t, "/custom/uploads", EnvConfig.UploadPath)
+		assert.Equal(t, "8080", EnvConfig.Port)
+		assert.Equal(t, "127.0.0.1", EnvConfig.Host)
+	})
+}

backend/internal/model/kv.go

@@ -0,0 +1,11 @@
+package model
+
+type KV struct {
+	Key   string `gorm:"primaryKey;not null"`
+	Value *string
+}
+
+// TableName overrides the table name used by KV to `kv`
+func (KV) TableName() string {
+	return "kv"
+}

backend/internal/service/app_config_service_test.go

@@ -4,10 +4,12 @@ import (
 	"sync/atomic"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
 	"github.com/pocket-id/pocket-id/backend/internal/common"
 	"github.com/pocket-id/pocket-id/backend/internal/dto"
 	"github.com/pocket-id/pocket-id/backend/internal/model"
-	"github.com/stretchr/testify/require"
+	testutils "github.com/pocket-id/pocket-id/backend/internal/utils/testing"
 )
 
 // NewTestAppConfigService is a function used by tests to create AppConfigService objects with pre-defined configuration values
@@ -22,7 +24,7 @@ func NewTestAppConfigService(config *model.AppConfig) *AppConfigService {
 
 func TestLoadDbConfig(t *testing.T) {
 	t.Run("empty config table", func(t *testing.T) {
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 		service := &AppConfigService{
 			db: db,
 		}
@@ -36,7 +38,7 @@ func TestLoadDbConfig(t *testing.T) {
 	})
 
 	t.Run("loads value from config table", func(t *testing.T) {
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 
 		// Populate the config table with some initial values
 		err := db.
@@ -66,7 +68,7 @@ func TestLoadDbConfig(t *testing.T) {
 	})
 
 	t.Run("ignores unknown config keys", func(t *testing.T) {
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 
 		// Add an entry with a key that doesn't exist in the config struct
 		err := db.Create([]model.AppConfigVariable{
@@ -87,7 +89,7 @@ func TestLoadDbConfig(t *testing.T) {
 	})
 
 	t.Run("loading config multiple times", func(t *testing.T) {
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 
 		// Initial state
 		err := db.Create([]model.AppConfigVariable{
@@ -129,7 +131,7 @@ func TestLoadDbConfig(t *testing.T) {
 		common.EnvConfig.UiConfigDisabled = true
 
 		// Create database with config that should be ignored
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 		err := db.Create([]model.AppConfigVariable{
 			{Key: "appName", Value: "DB App"},
 			{Key: "sessionDuration", Value: "120"},
@@ -165,7 +167,7 @@ func TestLoadDbConfig(t *testing.T) {
 		common.EnvConfig.UiConfigDisabled = false
 
 		// Create database with config values that should take precedence
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 		err := db.Create([]model.AppConfigVariable{
 			{Key: "appName", Value: "DB App"},
 			{Key: "sessionDuration", Value: "120"},
@@ -189,7 +191,7 @@ func TestLoadDbConfig(t *testing.T) {
 
 func TestUpdateAppConfigValues(t *testing.T) {
 	t.Run("update single value", func(t *testing.T) {
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 
 		// Create a service with default config
 		service := &AppConfigService{
@@ -214,7 +216,7 @@ func TestUpdateAppConfigValues(t *testing.T) {
 	})
 
 	t.Run("update multiple values", func(t *testing.T) {
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 
 		// Create a service with default config
 		service := &AppConfigService{
@@ -258,7 +260,7 @@ func TestUpdateAppConfigValues(t *testing.T) {
 	})
 
 	t.Run("empty value resets to default", func(t *testing.T) {
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 
 		// Create a service with default config
 		service := &AppConfigService{
@@ -279,7 +281,7 @@ func TestUpdateAppConfigValues(t *testing.T) {
 	})
 
 	t.Run("error with odd number of arguments", func(t *testing.T) {
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 
 		// Create a service with default config
 		service := &AppConfigService{
@@ -295,7 +297,7 @@ func TestUpdateAppConfigValues(t *testing.T) {
 	})
 
 	t.Run("error with invalid key", func(t *testing.T) {
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 
 		// Create a service with default config
 		service := &AppConfigService{
@@ -313,7 +315,7 @@ func TestUpdateAppConfigValues(t *testing.T) {
 
 func TestUpdateAppConfig(t *testing.T) {
 	t.Run("updates configuration values from DTO", func(t *testing.T) {
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 
 		// Create a service with default config
 		service := &AppConfigService{
@@ -386,7 +388,7 @@ func TestUpdateAppConfig(t *testing.T) {
 	})
 
 	t.Run("empty values reset to defaults", func(t *testing.T) {
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 
 		// Create a service with default config and modify some values
 		service := &AppConfigService{
@@ -451,7 +453,7 @@ func TestUpdateAppConfig(t *testing.T) {
 		// Disable UI config
 		common.EnvConfig.UiConfigDisabled = true
 
-		db := newDatabaseForTest(t)
+		db := testutils.NewDatabaseForTest(t)
 		service := &AppConfigService{
 			db: db,
 		}

backend/internal/service/e2etest_service.go

@@ -17,6 +17,7 @@ import (
 
 	"github.com/fxamacker/cbor/v2"
 	"github.com/go-webauthn/webauthn/protocol"
+	"github.com/lestrrat-go/jwx/v3/jwa"
 	"github.com/lestrrat-go/jwx/v3/jwk"
 	"github.com/lestrrat-go/jwx/v3/jwt"
 	"gorm.io/gorm"
@@ -25,6 +26,7 @@ import (
 	"github.com/pocket-id/pocket-id/backend/internal/model"
 	datatype "github.com/pocket-id/pocket-id/backend/internal/model/types"
 	"github.com/pocket-id/pocket-id/backend/internal/utils"
+	jwkutils "github.com/pocket-id/pocket-id/backend/internal/utils/jwk"
 	"github.com/pocket-id/pocket-id/backend/resources"
 )
 
@@ -60,7 +62,7 @@ func (s *TestService) initExternalIdP() error {
 		return fmt.Errorf("failed to generate private key: %w", err)
 	}
 
-	s.externalIdPKey, err = utils.ImportRawKey(rawKey)
+	s.externalIdPKey, err = jwkutils.ImportRawKey(rawKey, jwa.ES256().String(), "")
 	if err != nil {
 		return fmt.Errorf("failed to import private key: %w", err)
 	}

backend/internal/service/jwt_service.go

@@ -2,23 +2,20 @@ package service
 
 import (
 	"context"
-	"crypto/rand"
-	"crypto/rsa"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"log"
-	"os"
-	"path/filepath"
 	"time"
 
 	"github.com/lestrrat-go/jwx/v3/jwa"
 	"github.com/lestrrat-go/jwx/v3/jwk"
 	"github.com/lestrrat-go/jwx/v3/jwt"
+	"gorm.io/gorm"
 
 	"github.com/pocket-id/pocket-id/backend/internal/common"
 	"github.com/pocket-id/pocket-id/backend/internal/model"
-	"github.com/pocket-id/pocket-id/backend/internal/utils"
+	jwkutils "github.com/pocket-id/pocket-id/backend/internal/utils/jwk"
 )
 
 const (
@@ -26,8 +23,9 @@ const (
 	// This is a JSON file containing a key encoded as JWK
 	PrivateKeyFile = "jwt_private_key.json"
 
-	// RsaKeySize is the size, in bits, of the RSA key to generate if none is found
+	// PrivateKeyFileEncrypted is the path in the data/keys folder where the encrypted key is stored
-	RsaKeySize = 2048
+	// This is a encrypted JSON file containing a key encoded as JWK
+	PrivateKeyFileEncrypted = "jwt_private_key.json.enc"
 
 	// KeyUsageSigning is the usage for the private keys, for the "use" property
 	KeyUsageSigning = "sig"
@@ -59,58 +57,74 @@ const (
 )
 
 type JwtService struct {
+	envConfig        *common.EnvConfigSchema
 	privateKey       jwk.Key
 	keyId            string
 	appConfigService *AppConfigService
 	jwksEncoded      []byte
 }
 
-func NewJwtService(appConfigService *AppConfigService) *JwtService {
+func NewJwtService(db *gorm.DB, appConfigService *AppConfigService) *JwtService {
 	service := &JwtService{}
 
 	// Ensure keys are generated or loaded
-	if err := service.init(appConfigService, common.EnvConfig.KeysPath); err != nil {
+	err := service.init(db, appConfigService, &common.EnvConfig)
+	if err != nil {
 		log.Fatalf("Failed to initialize jwt service: %v", err)
 	}
 
 	return service
 }
 
-func (s *JwtService) init(appConfigService *AppConfigService, keysPath string) error {
+func (s *JwtService) init(db *gorm.DB, appConfigService *AppConfigService, envConfig *common.EnvConfigSchema) (err error) {
 	s.appConfigService = appConfigService
+	s.envConfig = envConfig
 
 	// Ensure keys are generated or loaded
-	return s.loadOrGenerateKey(keysPath)
+	return s.loadOrGenerateKey(db)
 }
 
-// loadOrGenerateKey loads the private key from the given path or generates it if not existing.
+func (s *JwtService) loadOrGenerateKey(db *gorm.DB) error {
-func (s *JwtService) loadOrGenerateKey(keysPath string) error {
+	// Get the key provider
-	var key jwk.Key
+	keyProvider, err := jwkutils.GetKeyProvider(db, s.envConfig, s.appConfigService.GetDbConfig().InstanceID.Value)
-
-	// First, check if we have a JWK file
-	// If we do, then we just load that
-	jwkPath := filepath.Join(keysPath, PrivateKeyFile)
-	ok, err := utils.FileExists(jwkPath)
 	if err != nil {
-		return fmt.Errorf("failed to check if private key file (JWK) exists at path '%s': %w", jwkPath, err)
+		return fmt.Errorf("failed to get key provider: %w", err)
 	}
-	if ok {
-		key, err = s.loadKeyJWK(jwkPath)
-		if err != nil {
-			return fmt.Errorf("failed to load private key file (JWK) at path '%s': %w", jwkPath, err)
-		}
 
-		// Set the key, and we are done
+	// Try loading a key
+	key, err := keyProvider.LoadKey()
+	if err != nil {
+		return fmt.Errorf("failed to load key (provider type '%s'): %w", s.envConfig.KeysStorage, err)
+	}
+
+	// If we have a key, store it in the object and we're done
+	if key != nil {
 		err = s.SetKey(key)
 		if err != nil {
 			return fmt.Errorf("failed to set private key: %w", err)
 		}
-
 		return nil
 	}
 
 	// If we are here, we need to generate a new key
-	key, err = s.generateNewRSAKey()
+	err = s.generateKey()
+	if err != nil {
+		return fmt.Errorf("failed to generate key: %w", err)
+	}
+
+	// Save the newly-generated key
+	err = keyProvider.SaveKey(s.privateKey)
+	if err != nil {
+		return fmt.Errorf("failed to save private key (provider type '%s'): %w", s.envConfig.KeysStorage, err)
+	}
+
+	return nil
+}
+
+// generateKey generates a new key and stores it in the object
+func (s *JwtService) generateKey() error {
+	// Default is to generate RS256 (RSA-2048) keys
+	key, err := jwkutils.GenerateKey(jwa.RS256().String(), "")
 	if err != nil {
 		return fmt.Errorf("failed to generate new private key: %w", err)
 	}
@@ -121,12 +135,6 @@ func (s *JwtService) loadOrGenerateKey(keysPath string) error {
 		return fmt.Errorf("failed to set private key: %w", err)
 	}
 
-	// Save the key as JWK
-	err = SaveKeyJWK(s.privateKey, jwkPath)
-	if err != nil {
-		return fmt.Errorf("failed to save private key file at path '%s': %w", jwkPath, err)
-	}
-
 	return nil
 }
 
@@ -192,13 +200,13 @@ func (s *JwtService) GenerateAccessToken(user model.User) (string, error) {
 		Subject(user.ID).
 		Expiration(now.Add(s.appConfigService.GetDbConfig().SessionDuration.AsDurationMinutes())).
 		IssuedAt(now).
-		Issuer(common.EnvConfig.AppURL).
+		Issuer(s.envConfig.AppURL).
 		Build()
 	if err != nil {
 		return "", fmt.Errorf("failed to build token: %w", err)
 	}
 
-	err = SetAudienceString(token, common.EnvConfig.AppURL)
+	err = SetAudienceString(token, s.envConfig.AppURL)
 	if err != nil {
 		return "", fmt.Errorf("failed to set 'aud' claim in token: %w", err)
 	}
@@ -229,8 +237,8 @@ func (s *JwtService) VerifyAccessToken(tokenString string) (jwt.Token, error) {
 		jwt.WithValidate(true),
 		jwt.WithKey(alg, s.privateKey),
 		jwt.WithAcceptableSkew(clockSkew),
-		jwt.WithAudience(common.EnvConfig.AppURL),
+		jwt.WithAudience(s.envConfig.AppURL),
-		jwt.WithIssuer(common.EnvConfig.AppURL),
+		jwt.WithIssuer(s.envConfig.AppURL),
 		jwt.WithValidator(TokenTypeValidator(AccessTokenJWTType)),
 	)
 	if err != nil {
@@ -246,7 +254,7 @@ func (s *JwtService) BuildIDToken(userClaims map[string]any, clientID string, no
 	token, err := jwt.NewBuilder().
 		Expiration(now.Add(1 * time.Hour)).
 		IssuedAt(now).
-		Issuer(common.EnvConfig.AppURL).
+		Issuer(s.envConfig.AppURL).
 		Build()
 	if err != nil {
 		return nil, fmt.Errorf("failed to build token: %w", err)
@@ -305,7 +313,7 @@ func (s *JwtService) VerifyIdToken(tokenString string, acceptExpiredTokens bool)
 		jwt.WithValidate(true),
 		jwt.WithKey(alg, s.privateKey),
 		jwt.WithAcceptableSkew(clockSkew),
-		jwt.WithIssuer(common.EnvConfig.AppURL),
+		jwt.WithIssuer(s.envConfig.AppURL),
 		jwt.WithValidator(TokenTypeValidator(IDTokenJWTType)),
 	)
 
@@ -335,7 +343,7 @@ func (s *JwtService) BuildOAuthAccessToken(user model.User, clientID string) (jw
 		Subject(user.ID).
 		Expiration(now.Add(1 * time.Hour)).
 		IssuedAt(now).
-		Issuer(common.EnvConfig.AppURL).
+		Issuer(s.envConfig.AppURL).
 		Build()
 	if err != nil {
 		return nil, fmt.Errorf("failed to build token: %w", err)
@@ -377,7 +385,7 @@ func (s *JwtService) VerifyOAuthAccessToken(tokenString string) (jwt.Token, erro
 		jwt.WithValidate(true),
 		jwt.WithKey(alg, s.privateKey),
 		jwt.WithAcceptableSkew(clockSkew),
-		jwt.WithIssuer(common.EnvConfig.AppURL),
+		jwt.WithIssuer(s.envConfig.AppURL),
 		jwt.WithValidator(TokenTypeValidator(OAuthAccessTokenJWTType)),
 	)
 	if err != nil {
@@ -393,7 +401,7 @@ func (s *JwtService) GenerateOAuthRefreshToken(userID string, clientID string, r
 		Subject(userID).
 		Expiration(now.Add(RefreshTokenDuration)).
 		IssuedAt(now).
-		Issuer(common.EnvConfig.AppURL).
+		Issuer(s.envConfig.AppURL).
 		Build()
 	if err != nil {
 		return "", fmt.Errorf("failed to build token: %w", err)
@@ -430,7 +438,7 @@ func (s *JwtService) VerifyOAuthRefreshToken(tokenString string) (userID, client
 		jwt.WithValidate(true),
 		jwt.WithKey(alg, s.privateKey),
 		jwt.WithAcceptableSkew(clockSkew),
-		jwt.WithIssuer(common.EnvConfig.AppURL),
+		jwt.WithIssuer(s.envConfig.AppURL),
 		jwt.WithValidator(TokenTypeValidator(OAuthRefreshTokenJWTType)),
 	)
 	if err != nil {
@@ -488,7 +496,7 @@ func (s *JwtService) GetPublicJWK() (jwk.Key, error) {
 		return nil, fmt.Errorf("failed to get public key: %w", err)
 	}
 
-	utils.EnsureAlgInKey(pubKey)
+	jwkutils.EnsureAlgInKey(pubKey, "", "")
 
 	return pubKey, nil
 }
@@ -517,56 +525,6 @@ func (s *JwtService) GetKeyAlg() (jwa.KeyAlgorithm, error) {
 	return alg, nil
 }
 
-func (s *JwtService) loadKeyJWK(path string) (jwk.Key, error) {
-	data, err := os.ReadFile(path)
-	if err != nil {
-		return nil, fmt.Errorf("failed to read key data: %w", err)
-	}
-
-	key, err := jwk.ParseKey(data)
-	if err != nil {
-		return nil, fmt.Errorf("failed to parse key: %w", err)
-	}
-
-	return key, nil
-}
-
-func (s *JwtService) generateNewRSAKey() (jwk.Key, error) {
-	// We generate RSA keys only
-	rawKey, err := rsa.GenerateKey(rand.Reader, RsaKeySize)
-	if err != nil {
-		return nil, fmt.Errorf("failed to generate RSA private key: %w", err)
-	}
-
-	// Import the raw key
-	return utils.ImportRawKey(rawKey)
-}
-
-// SaveKeyJWK saves a JWK to a file
-func SaveKeyJWK(key jwk.Key, path string) error {
-	dir := filepath.Dir(path)
-	err := os.MkdirAll(dir, 0700)
-	if err != nil {
-		return fmt.Errorf("failed to create directory '%s' for key file: %w", dir, err)
-	}
-
-	keyFile, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
-	if err != nil {
-		return fmt.Errorf("failed to create key file: %w", err)
-	}
-	defer keyFile.Close()
-
-	// Write the JSON file to disk
-	enc := json.NewEncoder(keyFile)
-	enc.SetEscapeHTML(false)
-	err = enc.Encode(key)
-	if err != nil {
-		return fmt.Errorf("failed to write key file: %w", err)
-	}
-
-	return nil
-}
-
 // GetIsAdmin returns the value of the "isAdmin" claim in the token
 func GetIsAdmin(token jwt.Token) (bool, error) {
 	if !token.Has(IsAdminClaim) {

backend/internal/service/jwt_service_test.go

@@ -21,7 +21,7 @@ import (
 
 	"github.com/pocket-id/pocket-id/backend/internal/common"
 	"github.com/pocket-id/pocket-id/backend/internal/model"
-	"github.com/pocket-id/pocket-id/backend/internal/utils"
+	jwkutils "github.com/pocket-id/pocket-id/backend/internal/utils/jwk"
 )
 
 func TestJwtService_Init(t *testing.T) {
@@ -33,9 +33,16 @@ func TestJwtService_Init(t *testing.T) {
 		// Create a temporary directory for the test
 		tempDir := t.TempDir()
 
+		// Setup the environment variable required by the token verification
+		mockEnvConfig := &common.EnvConfigSchema{
+			AppURL:      "https://test.example.com",
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		}
+
 		// Initialize the JWT service
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Verify the private key was set
@@ -66,9 +73,16 @@ func TestJwtService_Init(t *testing.T) {
 		// Create a temporary directory for the test
 		tempDir := t.TempDir()
 
+		// Setup the environment variable required by the token verification
+		mockEnvConfig := &common.EnvConfigSchema{
+			AppURL:      "https://test.example.com",
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		}
+
 		// First create a service to generate a key
 		firstService := &JwtService{}
-		err := firstService.init(mockConfig, tempDir)
+		err := firstService.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err)
 
 		// Get the key ID of the first service
@@ -77,7 +91,7 @@ func TestJwtService_Init(t *testing.T) {
 
 		// Now create a new service that should load the existing key
 		secondService := &JwtService{}
-		err = secondService.init(mockConfig, tempDir)
+		err = secondService.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err)
 
 		// Verify the loaded key has the same ID as the original
@@ -90,12 +104,19 @@ func TestJwtService_Init(t *testing.T) {
 		// Create a temporary directory for the test
 		tempDir := t.TempDir()
 
+		// Setup the environment variable required by the token verification
+		mockEnvConfig := &common.EnvConfigSchema{
+			AppURL:      "https://test.example.com",
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		}
+
 		// Create a new JWK and save it to disk
 		origKeyID := createECDSAKeyJWK(t, tempDir)
 
 		// Now create a new service that should load the existing key
 		svc := &JwtService{}
-		err := svc.init(mockConfig, tempDir)
+		err := svc.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err)
 
 		// Ensure loaded key has the right algorithm
@@ -113,12 +134,19 @@ func TestJwtService_Init(t *testing.T) {
 		// Create a temporary directory for the test
 		tempDir := t.TempDir()
 
+		// Setup the environment variable required by the token verification
+		mockEnvConfig := &common.EnvConfigSchema{
+			AppURL:      "https://test.example.com",
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		}
+
 		// Create a new JWK and save it to disk
 		origKeyID := createEdDSAKeyJWK(t, tempDir)
 
 		// Now create a new service that should load the existing key
 		svc := &JwtService{}
-		err := svc.init(mockConfig, tempDir)
+		err := svc.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err)
 
 		// Ensure loaded key has the right algorithm and curve
@@ -147,9 +175,16 @@ func TestJwtService_GetPublicJWK(t *testing.T) {
 		// Create a temporary directory for the test
 		tempDir := t.TempDir()
 
+		// Setup the environment variable required by the token verification
+		mockEnvConfig := &common.EnvConfigSchema{
+			AppURL:      "https://test.example.com",
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		}
+
 		// Create a JWT service with initialized key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Get the JWK (public key)
@@ -178,12 +213,19 @@ func TestJwtService_GetPublicJWK(t *testing.T) {
 		// Create a temporary directory for the test
 		tempDir := t.TempDir()
 
+		// Setup the environment variable required by the token verification
+		mockEnvConfig := &common.EnvConfigSchema{
+			AppURL:      "https://test.example.com",
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		}
+
 		// Create an ECDSA key and save it as JWK
 		originalKeyID := createECDSAKeyJWK(t, tempDir)
 
 		// Create a JWT service that loads the ECDSA key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Get the JWK (public key)
@@ -216,12 +258,19 @@ func TestJwtService_GetPublicJWK(t *testing.T) {
 		// Create a temporary directory for the test
 		tempDir := t.TempDir()
 
+		// Setup the environment variable required by the token verification
+		mockEnvConfig := &common.EnvConfigSchema{
+			AppURL:      "https://test.example.com",
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		}
+
 		// Create an EdDSA key and save it as JWK
 		originalKeyID := createEdDSAKeyJWK(t, tempDir)
 
 		// Create a JWT service that loads the EdDSA key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Get the JWK (public key)
@@ -276,16 +325,16 @@ func TestGenerateVerifyAccessToken(t *testing.T) {
 	})
 
 	// Setup the environment variable required by the token verification
-	originalAppURL := common.EnvConfig.AppURL
+	mockEnvConfig := &common.EnvConfigSchema{
-	common.EnvConfig.AppURL = "https://test.example.com"
+		AppURL:      "https://test.example.com",
-	defer func() {
+		KeysStorage: "file",
-		common.EnvConfig.AppURL = originalAppURL
+		KeysPath:    tempDir,
-	}()
+	}
 
 	t.Run("generates token for regular user", func(t *testing.T) {
 		// Create a JWT service
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Create a test user
@@ -328,7 +377,7 @@ func TestGenerateVerifyAccessToken(t *testing.T) {
 	t.Run("generates token for admin user", func(t *testing.T) {
 		// Create a JWT service
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Create a test admin user
@@ -364,7 +413,7 @@ func TestGenerateVerifyAccessToken(t *testing.T) {
 		})
 
 		service := &JwtService{}
-		err := service.init(customMockConfig, tempDir)
+		err := service.init(nil, customMockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Create a test user
@@ -399,7 +448,10 @@ func TestGenerateVerifyAccessToken(t *testing.T) {
 
 		// Create a JWT service that loads the key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		})
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Verify it loaded the right key
@@ -453,7 +505,10 @@ func TestGenerateVerifyAccessToken(t *testing.T) {
 
 		// Create a JWT service that loads the key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		})
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Verify it loaded the right key
@@ -507,7 +562,10 @@ func TestGenerateVerifyAccessToken(t *testing.T) {
 
 		// Create a JWT service that loads the key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		})
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Verify it loaded the right key
@@ -563,16 +621,16 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 	})
 
 	// Setup the environment variable required by the token verification
-	originalAppURL := common.EnvConfig.AppURL
+	mockEnvConfig := &common.EnvConfigSchema{
-	common.EnvConfig.AppURL = "https://test.example.com"
+		AppURL:      "https://test.example.com",
-	defer func() {
+		KeysStorage: "file",
-		common.EnvConfig.AppURL = originalAppURL
+		KeysPath:    tempDir,
-	}()
+	}
 
 	t.Run("generates and verifies ID token with standard claims", func(t *testing.T) {
 		// Create a JWT service
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Create test claims
@@ -601,7 +659,7 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 			assert.Equal(t, []string{clientID}, audience, "Audience should contain the client ID")
 		issuer, ok := claims.Issuer()
 		_ = assert.True(t, ok, "Issuer not found in token") &&
-			assert.Equal(t, common.EnvConfig.AppURL, issuer, "Issuer should match app URL")
+			assert.Equal(t, service.envConfig.AppURL, issuer, "Issuer should match app URL")
 
 		// Check token expiration time is approximately 1 hour from now
 		expectedExp := time.Now().Add(1 * time.Hour)
@@ -614,7 +672,7 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 	t.Run("can accept expired tokens if told so", func(t *testing.T) {
 		// Create a JWT service
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Create test claims
@@ -628,7 +686,7 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 		// Create a token that's already expired
 		token, err := jwt.NewBuilder().
 			Subject(userClaims["sub"].(string)).
-			Issuer(common.EnvConfig.AppURL).
+			Issuer(service.envConfig.AppURL).
 			Audience([]string{clientID}).
 			IssuedAt(time.Now().Add(-2 * time.Hour)).
 			Expiration(time.Now().Add(-1 * time.Hour)). // Expired 1 hour ago
@@ -666,13 +724,13 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 			assert.Equal(t, userClaims["sub"], subject, "Token subject should match user ID")
 		issuer, ok := claims.Issuer()
 		_ = assert.True(t, ok, "Issuer not found in token") &&
-			assert.Equal(t, common.EnvConfig.AppURL, issuer, "Issuer should match app URL")
+			assert.Equal(t, service.envConfig.AppURL, issuer, "Issuer should match app URL")
 	})
 
 	t.Run("generates and verifies ID token with nonce", func(t *testing.T) {
 		// Create a JWT service
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Create test claims with nonce
@@ -703,7 +761,7 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 	t.Run("fails verification with incorrect issuer", func(t *testing.T) {
 		// Create a JWT service
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Generate a token with standard claims
@@ -714,7 +772,7 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 		require.NoError(t, err, "Failed to generate ID token")
 
 		// Temporarily change the app URL to simulate wrong issuer
-		common.EnvConfig.AppURL = "https://wrong-issuer.com"
+		service.envConfig.AppURL = "https://wrong-issuer.com"
 
 		// Verify should fail due to issuer mismatch
 		_, err = service.VerifyIdToken(tokenString, false)
@@ -731,7 +789,10 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 
 		// Create a JWT service that loads the key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		})
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Verify it loaded the right key
@@ -762,7 +823,7 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 			assert.Equal(t, "eddsauser456", subject, "Token subject should match user ID")
 		issuer, ok := claims.Issuer()
 		_ = assert.True(t, ok, "Issuer not found in token") &&
-			assert.Equal(t, common.EnvConfig.AppURL, issuer, "Issuer should match app URL")
+			assert.Equal(t, service.envConfig.AppURL, issuer, "Issuer should match app URL")
 
 		// Verify the key type is OKP
 		publicKey, err := service.GetPublicJWK()
@@ -784,7 +845,10 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 
 		// Create a JWT service that loads the key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		})
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Verify it loaded the right key
@@ -795,7 +859,6 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 		// Create test claims
 		userClaims := map[string]interface{}{
 			"sub":   "ecdsauser456",
-			"name":  "ECDSA User",
 			"email": "ecdsauser@example.com",
 		}
 		const clientID = "ecdsa-client-123"
@@ -815,7 +878,7 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 			assert.Equal(t, "ecdsauser456", subject, "Token subject should match user ID")
 		issuer, ok := claims.Issuer()
 		_ = assert.True(t, ok, "Issuer not found in token") &&
-			assert.Equal(t, common.EnvConfig.AppURL, issuer, "Issuer should match app URL")
+			assert.Equal(t, service.envConfig.AppURL, issuer, "Issuer should match app URL")
 
 		// Verify the key type is EC
 		publicKey, err := service.GetPublicJWK()
@@ -837,7 +900,10 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 
 		// Create a JWT service that loads the key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		})
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Verify it loaded the right key
@@ -868,17 +934,7 @@ func TestGenerateVerifyIdToken(t *testing.T) {
 			assert.Equal(t, "rsauser456", subject, "Token subject should match user ID")
 		issuer, ok := claims.Issuer()
 		_ = assert.True(t, ok, "Issuer not found in token") &&
-			assert.Equal(t, common.EnvConfig.AppURL, issuer, "Issuer should match app URL")
+			assert.Equal(t, service.envConfig.AppURL, issuer, "Issuer should match app URL")
-
-		// Verify the key type is RSA
-		publicKey, err := service.GetPublicJWK()
-		require.NoError(t, err)
-		assert.Equal(t, jwa.RSA().String(), publicKey.KeyType().String(), "Key type should be RSA")
-
-		// Verify the algorithm is RS256
-		alg, ok := publicKey.Algorithm()
-		require.True(t, ok)
-		assert.Equal(t, jwa.RS256().String(), alg.String(), "Algorithm should be RS256")
 	})
 }
 
@@ -892,16 +948,16 @@ func TestGenerateVerifyOAuthAccessToken(t *testing.T) {
 	})
 
 	// Setup the environment variable required by the token verification
-	originalAppURL := common.EnvConfig.AppURL
+	mockEnvConfig := &common.EnvConfigSchema{
-	common.EnvConfig.AppURL = "https://test.example.com"
+		AppURL:      "https://test.example.com",
-	defer func() {
+		KeysStorage: "file",
-		common.EnvConfig.AppURL = originalAppURL
+		KeysPath:    tempDir,
-	}()
+	}
 
 	t.Run("generates and verifies OAuth access token with standard claims", func(t *testing.T) {
 		// Create a JWT service
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Create a test user
@@ -931,7 +987,7 @@ func TestGenerateVerifyOAuthAccessToken(t *testing.T) {
 			assert.Equal(t, []string{clientID}, audience, "Audience should contain the client ID")
 		issuer, ok := claims.Issuer()
 		_ = assert.True(t, ok, "Issuer not found in token") &&
-			assert.Equal(t, common.EnvConfig.AppURL, issuer, "Issuer should match app URL")
+			assert.Equal(t, service.envConfig.AppURL, issuer, "Issuer should match app URL")
 
 		// Check token expiration time is approximately 1 hour from now
 		expectedExp := time.Now().Add(1 * time.Hour)
@@ -944,7 +1000,7 @@ func TestGenerateVerifyOAuthAccessToken(t *testing.T) {
 	t.Run("fails verification for expired token", func(t *testing.T) {
 		// Create a JWT service with a mock function to generate an expired token
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Create a test user
@@ -961,7 +1017,7 @@ func TestGenerateVerifyOAuthAccessToken(t *testing.T) {
 			Expiration(time.Now().Add(-1 * time.Hour)). // Expired 1 hour ago
 			IssuedAt(time.Now().Add(-2 * time.Hour)).
 			Audience([]string{clientID}).
-			Issuer(common.EnvConfig.AppURL).
+			Issuer(service.envConfig.AppURL).
 			Build()
 		require.NoError(t, err, "Failed to build token")
 
@@ -980,11 +1036,17 @@ func TestGenerateVerifyOAuthAccessToken(t *testing.T) {
 	t.Run("fails verification with invalid signature", func(t *testing.T) {
 		// Create two JWT services with different keys
 		service1 := &JwtService{}
-		err := service1.init(mockConfig, t.TempDir()) // Use a different temp dir
+		err := service1.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    t.TempDir(), // Use a different temp dir
+		})
 		require.NoError(t, err, "Failed to initialize first JWT service")
 
 		service2 := &JwtService{}
-		err = service2.init(mockConfig, t.TempDir()) // Use a different temp dir
+		err = service2.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    t.TempDir(), // Use a different temp dir
+		})
 		require.NoError(t, err, "Failed to initialize second JWT service")
 
 		// Create a test user
@@ -1014,7 +1076,10 @@ func TestGenerateVerifyOAuthAccessToken(t *testing.T) {
 
 		// Create a JWT service that loads the key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		})
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Verify it loaded the right key
@@ -1068,7 +1133,10 @@ func TestGenerateVerifyOAuthAccessToken(t *testing.T) {
 
 		// Create a JWT service that loads the key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		})
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Verify it loaded the right key
@@ -1122,7 +1190,10 @@ func TestGenerateVerifyOAuthAccessToken(t *testing.T) {
 
 		// Create a JWT service that loads the key
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    tempDir,
+		})
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Verify it loaded the right key
@@ -1176,16 +1247,16 @@ func TestGenerateVerifyOAuthRefreshToken(t *testing.T) {
 	mockConfig := NewTestAppConfigService(&model.AppConfig{})
 
 	// Setup the environment variable required by the token verification
-	originalAppURL := common.EnvConfig.AppURL
+	mockEnvConfig := &common.EnvConfigSchema{
-	common.EnvConfig.AppURL = "https://test.example.com"
+		AppURL:      "https://test.example.com",
-	defer func() {
+		KeysStorage: "file",
-		common.EnvConfig.AppURL = originalAppURL
+		KeysPath:    tempDir,
-	}()
+	}
 
 	t.Run("generates and verifies refresh token", func(t *testing.T) {
 		// Create a JWT service
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Create a test user
@@ -1211,7 +1282,7 @@ func TestGenerateVerifyOAuthRefreshToken(t *testing.T) {
 	t.Run("fails verification for expired token", func(t *testing.T) {
 		// Create a JWT service
 		service := &JwtService{}
-		err := service.init(mockConfig, tempDir)
+		err := service.init(nil, mockConfig, mockEnvConfig)
 		require.NoError(t, err, "Failed to initialize JWT service")
 
 		// Generate a token using JWT directly to create an expired token
@@ -1220,7 +1291,7 @@ func TestGenerateVerifyOAuthRefreshToken(t *testing.T) {
 			Expiration(time.Now().Add(-1 * time.Hour)). // Expired 1 hour ago
 			IssuedAt(time.Now().Add(-2 * time.Hour)).
 			Audience([]string{"client123"}).
-			Issuer(common.EnvConfig.AppURL).
+			Issuer(service.envConfig.AppURL).
 			Build()
 		require.NoError(t, err, "Failed to build token")
 
@@ -1236,11 +1307,17 @@ func TestGenerateVerifyOAuthRefreshToken(t *testing.T) {
 	t.Run("fails verification with invalid signature", func(t *testing.T) {
 		// Create two JWT services with different keys
 		service1 := &JwtService{}
-		err := service1.init(mockConfig, t.TempDir())
+		err := service1.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    t.TempDir(), // Use a different temp dir
+		})
 		require.NoError(t, err, "Failed to initialize first JWT service")
 
 		service2 := &JwtService{}
-		err = service2.init(mockConfig, t.TempDir())
+		err = service2.init(nil, mockConfig, &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    t.TempDir(), // Use a different temp dir
+		})
 		require.NoError(t, err, "Failed to initialize second JWT service")
 
 		// Generate a token with the first service
@@ -1308,7 +1385,10 @@ func TestGetTokenType(t *testing.T) {
 	// Initialize the JWT service
 	mockConfig := NewTestAppConfigService(&model.AppConfig{})
 	service := &JwtService{}
-	err := service.init(mockConfig, tempDir)
+	err := service.init(nil, mockConfig, &common.EnvConfigSchema{
+		KeysStorage: "file",
+		KeysPath:    tempDir,
+	})
 	require.NoError(t, err, "Failed to initialize JWT service")
 
 	buildTokenForType := func(t *testing.T, typ string, setClaimsFn func(b *jwt.Builder)) string {
@@ -1402,10 +1482,19 @@ func TestGetTokenType(t *testing.T) {
 func importKey(t *testing.T, privateKeyRaw any, path string) string {
 	t.Helper()
 
-	privateKey, err := utils.ImportRawKey(privateKeyRaw)
+	privateKey, err := jwkutils.ImportRawKey(privateKeyRaw, "", "")
 	require.NoError(t, err, "Failed to import private key")
 
-	err = SaveKeyJWK(privateKey, filepath.Join(path, PrivateKeyFile))
+	keyProvider := &jwkutils.KeyProviderFile{}
+	err = keyProvider.Init(jwkutils.KeyProviderOpts{
+		EnvConfig: &common.EnvConfigSchema{
+			KeysStorage: "file",
+			KeysPath:    path,
+		},
+	})
+	require.NoError(t, err, "Failed to init file key provider")
+
+	err = keyProvider.SaveKey(privateKey)
 	require.NoError(t, err, "Failed to save key")
 
 	kid, _ := privateKey.KeyID()

backend/internal/service/oidc_service_test.go

@@ -18,6 +18,7 @@ import (
 
 	"github.com/pocket-id/pocket-id/backend/internal/common"
 	"github.com/pocket-id/pocket-id/backend/internal/dto"
+	testutils "github.com/pocket-id/pocket-id/backend/internal/utils/testing"
 )
 
 // generateTestECDSAKey creates an ECDSA key for testing
@@ -62,12 +63,12 @@ func TestOidcService_jwkSetForURL(t *testing.T) {
 	)
 	mockResponses := map[string]*http.Response{
 		//nolint:bodyclose
-		url1: NewMockResponse(http.StatusOK, string(jwkSetJSON1)),
+		url1: testutils.NewMockResponse(http.StatusOK, string(jwkSetJSON1)),
 		//nolint:bodyclose
-		url2: NewMockResponse(http.StatusOK, string(jwkSetJSON2)),
+		url2: testutils.NewMockResponse(http.StatusOK, string(jwkSetJSON2)),
 	}
 	httpClient := &http.Client{
-		Transport: &MockRoundTripper{
+		Transport: &testutils.MockRoundTripper{
 			Responses: mockResponses,
 		},
 	}
@@ -139,7 +140,7 @@ func TestOidcService_verifyClientCredentialsInternal(t *testing.T) {
 
 	var err error
 	// Create a test database
-	db := newDatabaseForTest(t)
+	db := testutils.NewDatabaseForTest(t)
 
 	// Create two JWKs for testing
 	privateJWK, jwkSetJSON := generateTestECDSAKey(t)
@@ -149,12 +150,12 @@ func TestOidcService_verifyClientCredentialsInternal(t *testing.T) {
 
 	// Create a mock HTTP client with custom transport to return the JWKS
 	httpClient := &http.Client{
-		Transport: &MockRoundTripper{
+		Transport: &testutils.MockRoundTripper{
 			Responses: map[string]*http.Response{
 				//nolint:bodyclose
-				federatedClientIssuer + "/jwks.json": NewMockResponse(http.StatusOK, string(jwkSetJSON)),
+				federatedClientIssuer + "/jwks.json": testutils.NewMockResponse(http.StatusOK, string(jwkSetJSON)),
 				//nolint:bodyclose
-				federatedClientIssuerDefaults + ".well-known/jwks.json": NewMockResponse(http.StatusOK, string(jwkSetJSONDefaults)),
+				federatedClientIssuerDefaults + ".well-known/jwks.json": testutils.NewMockResponse(http.StatusOK, string(jwkSetJSONDefaults)),
 			},
 		},
 	}

backend/internal/utils/crypto/crypto.go

@@ -0,0 +1,69 @@
+package crypto
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"errors"
+	"fmt"
+	"io"
+)
+
+// ErrDecrypt is returned by Decrypt when the operation failed for any reason
+var ErrDecrypt = errors.New("failed to decrypt data")
+
+// Encrypt a byte slice using AES-GCM and a random nonce
+// Important: do not encrypt more than ~4 billion messages with the same key!
+func Encrypt(key []byte, plaintext []byte, associatedData []byte) (ciphertext []byte, err error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create block cipher: %w", err)
+	}
+	aead, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create AEAD cipher: %w", err)
+	}
+
+	// Generate a random nonce
+	nonce := make([]byte, aead.NonceSize())
+	_, err = io.ReadFull(rand.Reader, nonce)
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate random nonce: %w", err)
+	}
+
+	// Allocate the slice for the result, with additional space for the nonce and overhead
+	ciphertext = make([]byte, 0, len(plaintext)+aead.NonceSize()+aead.Overhead())
+	ciphertext = append(ciphertext, nonce...)
+
+	// Encrypt the plaintext
+	// Tag is automatically added at the end
+	ciphertext = aead.Seal(ciphertext, nonce, plaintext, associatedData)
+
+	return ciphertext, nil
+}
+
+// Decrypt a byte slice using AES-GCM
+func Decrypt(key []byte, ciphertext []byte, associatedData []byte) (plaintext []byte, err error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create block cipher: %w", err)
+	}
+	aead, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create AEAD cipher: %w", err)
+	}
+
+	// Extract the nonce
+	if len(ciphertext) < (aead.NonceSize() + aead.Overhead()) {
+		return nil, ErrDecrypt
+	}
+
+	// Decrypt the data
+	plaintext, err = aead.Open(nil, ciphertext[:aead.NonceSize()], ciphertext[aead.NonceSize():], associatedData)
+	if err != nil {
+		// Note: we do not return the exact error here, to avoid disclosing information
+		return nil, ErrDecrypt
+	}
+
+	return plaintext, nil
+}

backend/internal/utils/crypto/crypto_test.go

@@ -0,0 +1,208 @@
+package crypto
+
+import (
+	"crypto/rand"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestEncryptDecrypt(t *testing.T) {
+	tests := []struct {
+		name           string
+		keySize        int
+		plaintext      string
+		associatedData []byte
+	}{
+		{
+			name:           "AES-128 with short plaintext",
+			keySize:        16,
+			plaintext:      "Hello, World!",
+			associatedData: []byte("test-aad"),
+		},
+		{
+			name:           "AES-192 with medium plaintext",
+			keySize:        24,
+			plaintext:      "This is a longer message to test encryption and decryption",
+			associatedData: []byte("associated-data-192"),
+		},
+		{
+			name:           "AES-256 with unicode",
+			keySize:        32,
+			plaintext:      "Hello 世界! 🌍 Testing unicode characters", //nolint:gosmopolitan
+			associatedData: []byte("unicode-test"),
+		},
+		{
+			name:           "No associated data",
+			keySize:        32,
+			plaintext:      "Testing without associated data",
+			associatedData: nil,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Generate random key
+			key := make([]byte, tt.keySize)
+			_, err := rand.Read(key)
+			require.NoError(t, err, "Failed to generate random key")
+
+			plaintext := []byte(tt.plaintext)
+
+			// Test encryption
+			ciphertext, err := Encrypt(key, plaintext, tt.associatedData)
+			require.NoError(t, err, "Encrypt should succeed")
+
+			// Verify ciphertext is different from plaintext (unless empty)
+			if len(plaintext) > 0 {
+				assert.NotEqual(t, plaintext, ciphertext)
+			}
+
+			// Test decryption
+			decrypted, err := Decrypt(key, ciphertext, tt.associatedData)
+			require.NoError(t, err, "Decrypt should succeed")
+
+			// Verify decrypted text matches original
+			assert.Equal(t, plaintext, decrypted, "Decrypted text should match original")
+		})
+	}
+}
+
+func TestEncryptWithInvalidKeySize(t *testing.T) {
+	invalidKeySizes := []int{8, 12, 33, 47, 55, 128}
+
+	for _, keySize := range invalidKeySizes {
+		t.Run(fmt.Sprintf("Key size %d", keySize), func(t *testing.T) {
+			key := make([]byte, keySize)
+			plaintext := []byte("test message")
+
+			_, err := Encrypt(key, plaintext, nil)
+			require.Error(t, err)
+			assert.ErrorContains(t, err, "invalid key size")
+		})
+	}
+}
+
+func TestDecryptWithInvalidKeySize(t *testing.T) {
+	invalidKeySizes := []int{8, 12, 33, 47, 55, 128}
+
+	for _, keySize := range invalidKeySizes {
+		t.Run(fmt.Sprintf("Key size %d", keySize), func(t *testing.T) {
+			key := make([]byte, keySize)
+			ciphertext := []byte("fake ciphertext")
+
+			_, err := Decrypt(key, ciphertext, nil)
+			require.Error(t, err)
+			assert.ErrorContains(t, err, "invalid key size")
+		})
+	}
+}
+
+func TestDecryptWithInvalidCiphertext(t *testing.T) {
+	key := make([]byte, 32)
+	_, err := rand.Read(key)
+	require.NoError(t, err, "Failed to generate random key")
+
+	tests := []struct {
+		name       string
+		ciphertext []byte
+	}{
+		{
+			name:       "empty ciphertext",
+			ciphertext: []byte{},
+		},
+		{
+			name:       "too short ciphertext",
+			ciphertext: []byte("short"),
+		},
+		{
+			name:       "random invalid data",
+			ciphertext: []byte("this is not valid encrypted data"),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := Decrypt(key, tt.ciphertext, nil)
+			require.Error(t, err)
+			require.ErrorIs(t, err, ErrDecrypt)
+		})
+	}
+}
+
+func TestDecryptWithWrongKey(t *testing.T) {
+	// Generate two different keys
+	key1 := make([]byte, 32)
+	key2 := make([]byte, 32)
+	_, err := rand.Read(key1)
+	require.NoError(t, err)
+	_, err = rand.Read(key2)
+	require.NoError(t, err)
+
+	plaintext := []byte("secret message")
+
+	// Encrypt with key1
+	ciphertext, err := Encrypt(key1, plaintext, nil)
+	require.NoError(t, err)
+
+	// Try to decrypt with key2
+	_, err = Decrypt(key2, ciphertext, nil)
+	require.Error(t, err)
+	require.ErrorIs(t, err, ErrDecrypt)
+}
+
+func TestDecryptWithWrongAssociatedData(t *testing.T) {
+	key := make([]byte, 32)
+	_, err := rand.Read(key)
+	require.NoError(t, err, "Failed to generate random key")
+
+	plaintext := []byte("secret message")
+	correctAAD := []byte("correct-aad")
+	wrongAAD := []byte("wrong-aad")
+
+	// Encrypt with correct AAD
+	ciphertext, err := Encrypt(key, plaintext, correctAAD)
+	require.NoError(t, err)
+
+	// Try to decrypt with wrong AAD
+	_, err = Decrypt(key, ciphertext, wrongAAD)
+	require.Error(t, err)
+	require.ErrorIs(t, err, ErrDecrypt)
+
+	// Verify correct AAD works
+	decrypted, err := Decrypt(key, ciphertext, correctAAD)
+	require.NoError(t, err)
+	assert.Equal(t, plaintext, decrypted, "Decrypted text should match original when using correct AAD")
+}
+
+func TestEncryptDecryptConsistency(t *testing.T) {
+	key := make([]byte, 32)
+	_, err := rand.Read(key)
+	require.NoError(t, err)
+
+	plaintext := []byte("consistency test message")
+	associatedData := []byte("test-aad")
+
+	// Encrypt multiple times and verify we get different ciphertexts (due to random IV)
+	ciphertext1, err := Encrypt(key, plaintext, associatedData)
+	require.NoError(t, err)
+
+	ciphertext2, err := Encrypt(key, plaintext, associatedData)
+	require.NoError(t, err)
+
+	// Ciphertexts should be different (due to random IV)
+	assert.NotEqual(t, ciphertext1, ciphertext2, "Multiple encryptions of same plaintext should produce different ciphertexts")
+
+	// Both should decrypt to the same plaintext
+	decrypted1, err := Decrypt(key, ciphertext1, associatedData)
+	require.NoError(t, err)
+
+	decrypted2, err := Decrypt(key, ciphertext2, associatedData)
+	require.NoError(t, err)
+
+	assert.Equal(t, plaintext, decrypted1, "First decrypted text should match original")
+	assert.Equal(t, plaintext, decrypted2, "Second decrypted text should match original")
+	assert.Equal(t, decrypted1, decrypted2, "Both decrypted texts should be identical")
+}

backend/internal/utils/jwk/key_provider.go

@@ -0,0 +1,50 @@
+package jwk
+
+import (
+	"fmt"
+
+	"github.com/lestrrat-go/jwx/v3/jwk"
+	"gorm.io/gorm"
+
+	"github.com/pocket-id/pocket-id/backend/internal/common"
+)
+
+type KeyProviderOpts struct {
+	EnvConfig *common.EnvConfigSchema
+	DB        *gorm.DB
+	Kek       []byte
+}
+
+type KeyProvider interface {
+	Init(opts KeyProviderOpts) error
+	LoadKey() (jwk.Key, error)
+	SaveKey(key jwk.Key) error
+}
+
+func GetKeyProvider(db *gorm.DB, envConfig *common.EnvConfigSchema, instanceID string) (keyProvider KeyProvider, err error) {
+	// Load the encryption key (KEK) if present
+	kek, err := LoadKeyEncryptionKey(envConfig, instanceID)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load encryption key: %w", err)
+	}
+
+	// Get the key provider
+	switch envConfig.KeysStorage {
+	case "file", "":
+		keyProvider = &KeyProviderFile{}
+	case "database":
+		keyProvider = &KeyProviderDatabase{}
+	default:
+		return nil, fmt.Errorf("invalid key storage '%s'", envConfig.KeysStorage)
+	}
+	err = keyProvider.Init(KeyProviderOpts{
+		DB:        db,
+		EnvConfig: envConfig,
+		Kek:       kek,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to init key provider of type '%s': %w", envConfig.KeysStorage, err)
+	}
+
+	return keyProvider, nil
+}

backend/internal/utils/jwk/key_provider_database.go

@@ -0,0 +1,109 @@
+package jwk
+
+import (
+	"context"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/lestrrat-go/jwx/v3/jwk"
+	"gorm.io/gorm"
+
+	"github.com/pocket-id/pocket-id/backend/internal/model"
+	cryptoutils "github.com/pocket-id/pocket-id/backend/internal/utils/crypto"
+)
+
+const PrivateKeyDBKey = "jwt_private_key.json"
+
+type KeyProviderDatabase struct {
+	db  *gorm.DB
+	kek []byte
+}
+
+func (f *KeyProviderDatabase) Init(opts KeyProviderOpts) error {
+	if len(opts.Kek) == 0 {
+		return errors.New("an encryption key is required when using the 'database' key provider")
+	}
+
+	f.db = opts.DB
+	f.kek = opts.Kek
+
+	return nil
+}
+
+func (f *KeyProviderDatabase) LoadKey() (key jwk.Key, err error) {
+	row := model.KV{
+		Key: PrivateKeyDBKey,
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	err = f.db.WithContext(ctx).First(&row).Error
+	if errors.Is(err, gorm.ErrRecordNotFound) {
+		// Key not present in the database - return nil so a new one can be generated
+		return nil, nil
+	} else if err != nil {
+		return nil, fmt.Errorf("failed to retrieve private key from the database: %w", err)
+	}
+
+	if row.Value == nil || *row.Value == "" {
+		// Key not present in the database - return nil so a new one can be generated
+		return nil, nil
+	}
+
+	// Decode from base64
+	enc, err := base64.StdEncoding.DecodeString(*row.Value)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read encrypted private key: not a valid base64-encoded value: %w", err)
+	}
+
+	// Decrypt the data
+	data, err := cryptoutils.Decrypt(f.kek, enc, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to decrypt private key: %w", err)
+	}
+
+	// Parse the key
+	key, err = jwk.ParseKey(data)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse encrypted private key: %w", err)
+	}
+
+	return key, nil
+}
+
+func (f *KeyProviderDatabase) SaveKey(key jwk.Key) error {
+	// Encode the key to JSON
+	data, err := EncodeJWKBytes(key)
+	if err != nil {
+		return fmt.Errorf("failed to encode key to JSON: %w", err)
+	}
+
+	// Encrypt the key then encode to Base64
+	enc, err := cryptoutils.Encrypt(f.kek, data, nil)
+	if err != nil {
+		return fmt.Errorf("failed to encrypt key: %w", err)
+	}
+	encB64 := base64.StdEncoding.EncodeToString(enc)
+
+	// Save to database
+	row := model.KV{
+		Key:   PrivateKeyDBKey,
+		Value: &encB64,
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	err = f.db.WithContext(ctx).Create(&row).Error
+	if err != nil {
+		// There's one scenario where if Pocket ID is started fresh with more than 1 replica, they both could be trying to create the private key in the database at the same time
+		// In this case, only one of the replicas will succeed; the other one(s) will return an error here, which will cascade down and cause the replica(s) to crash and be restarted (at that point they'll load the then-existing key from the database)
+		return fmt.Errorf("failed to store private key in database: %w", err)
+	}
+
+	return nil
+}
+
+// Compile-time interface check
+var _ KeyProvider = (*KeyProviderDatabase)(nil)

backend/internal/utils/jwk/key_provider_database_test.go

@@ -0,0 +1,275 @@
+package jwk
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"encoding/base64"
+	"testing"
+
+	"github.com/lestrrat-go/jwx/v3/jwk"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/pocket-id/pocket-id/backend/internal/model"
+	cryptoutils "github.com/pocket-id/pocket-id/backend/internal/utils/crypto"
+	testutils "github.com/pocket-id/pocket-id/backend/internal/utils/testing"
+)
+
+func TestKeyProviderDatabase_Init(t *testing.T) {
+	t.Run("Init fails when KEK is not provided", func(t *testing.T) {
+		db := testutils.NewDatabaseForTest(t)
+		provider := &KeyProviderDatabase{}
+		err := provider.Init(KeyProviderOpts{
+			DB:  db,
+			Kek: nil, // No KEK
+		})
+		require.Error(t, err, "Expected error when KEK is not provided")
+		require.ErrorContains(t, err, "encryption key is required")
+	})
+
+	t.Run("Init succeeds with KEK", func(t *testing.T) {
+		db := testutils.NewDatabaseForTest(t)
+		provider := &KeyProviderDatabase{}
+		err := provider.Init(KeyProviderOpts{
+			DB:  db,
+			Kek: generateTestKEK(t),
+		})
+		require.NoError(t, err, "Expected no error when KEK is provided")
+	})
+}
+
+func TestKeyProviderDatabase_LoadKey(t *testing.T) {
+	// Generate a test key to use in our tests
+	pk, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	require.NoError(t, err)
+
+	key, err := jwk.Import(pk)
+	require.NoError(t, err)
+
+	t.Run("LoadKey with no existing key", func(t *testing.T) {
+		db := testutils.NewDatabaseForTest(t)
+		kek := generateTestKEK(t)
+
+		provider := &KeyProviderDatabase{}
+		err := provider.Init(KeyProviderOpts{
+			DB:  db,
+			Kek: kek,
+		})
+		require.NoError(t, err)
+
+		// Load key when none exists
+		loadedKey, err := provider.LoadKey()
+		require.NoError(t, err)
+		assert.Nil(t, loadedKey, "Expected nil key when no key exists in database")
+	})
+
+	t.Run("LoadKey with existing key", func(t *testing.T) {
+		db := testutils.NewDatabaseForTest(t)
+		kek := generateTestKEK(t)
+
+		provider := &KeyProviderDatabase{}
+		err := provider.Init(KeyProviderOpts{
+			DB:  db,
+			Kek: kek,
+		})
+		require.NoError(t, err)
+
+		// Save a key
+		err = provider.SaveKey(key)
+		require.NoError(t, err)
+
+		// Load the key
+		loadedKey, err := provider.LoadKey()
+		require.NoError(t, err)
+		assert.NotNil(t, loadedKey, "Expected non-nil key when key exists in database")
+
+		// Verify the loaded key is the same as the original
+		keyBytes, err := EncodeJWKBytes(key)
+		require.NoError(t, err)
+
+		loadedKeyBytes, err := EncodeJWKBytes(loadedKey)
+		require.NoError(t, err)
+
+		assert.Equal(t, keyBytes, loadedKeyBytes, "Expected loaded key to match original key")
+	})
+
+	t.Run("LoadKey with invalid base64", func(t *testing.T) {
+		db := testutils.NewDatabaseForTest(t)
+		kek := generateTestKEK(t)
+
+		provider := &KeyProviderDatabase{}
+		err := provider.Init(KeyProviderOpts{
+			DB:  db,
+			Kek: kek,
+		})
+		require.NoError(t, err)
+
+		// Insert invalid base64 data
+		invalidBase64 := "not-valid-base64"
+		err = db.Create(&model.KV{
+			Key:   PrivateKeyDBKey,
+			Value: &invalidBase64,
+		}).Error
+		require.NoError(t, err)
+
+		// Attempt to load the key
+		loadedKey, err := provider.LoadKey()
+		require.Error(t, err, "Expected error when loading key with invalid base64")
+		require.ErrorContains(t, err, "not a valid base64-encoded value")
+		assert.Nil(t, loadedKey, "Expected nil key when loading fails")
+	})
+
+	t.Run("LoadKey with invalid encrypted data", func(t *testing.T) {
+		db := testutils.NewDatabaseForTest(t)
+		kek := generateTestKEK(t)
+
+		provider := &KeyProviderDatabase{}
+		err := provider.Init(KeyProviderOpts{
+			DB:  db,
+			Kek: kek,
+		})
+		require.NoError(t, err)
+
+		// Insert valid base64 but invalid encrypted data
+		invalidData := base64.StdEncoding.EncodeToString([]byte("not-valid-encrypted-data"))
+		err = db.Create(&model.KV{
+			Key:   PrivateKeyDBKey,
+			Value: &invalidData,
+		}).Error
+		require.NoError(t, err)
+
+		// Attempt to load the key
+		loadedKey, err := provider.LoadKey()
+		require.Error(t, err, "Expected error when loading key with invalid encrypted data")
+		require.ErrorContains(t, err, "failed to decrypt")
+		assert.Nil(t, loadedKey, "Expected nil key when loading fails")
+	})
+
+	t.Run("LoadKey with valid encrypted data but wrong KEK", func(t *testing.T) {
+		db := testutils.NewDatabaseForTest(t)
+		originalKek := generateTestKEK(t)
+
+		// Save a key with the original KEK
+		originalProvider := &KeyProviderDatabase{}
+		err := originalProvider.Init(KeyProviderOpts{
+			DB:  db,
+			Kek: originalKek,
+		})
+		require.NoError(t, err)
+
+		err = originalProvider.SaveKey(key)
+		require.NoError(t, err)
+
+		// Now try to load with a different KEK
+		differentKek := generateTestKEK(t)
+		differentProvider := &KeyProviderDatabase{}
+		err = differentProvider.Init(KeyProviderOpts{
+			DB:  db,
+			Kek: differentKek,
+		})
+		require.NoError(t, err)
+
+		// Attempt to load the key with the wrong KEK
+		loadedKey, err := differentProvider.LoadKey()
+		require.Error(t, err, "Expected error when loading key with wrong KEK")
+		require.ErrorContains(t, err, "failed to decrypt")
+		assert.Nil(t, loadedKey, "Expected nil key when loading fails")
+	})
+
+	t.Run("LoadKey with invalid key data", func(t *testing.T) {
+		db := testutils.NewDatabaseForTest(t)
+		kek := generateTestKEK(t)
+
+		provider := &KeyProviderDatabase{}
+		err := provider.Init(KeyProviderOpts{
+			DB:  db,
+			Kek: kek,
+		})
+		require.NoError(t, err)
+
+		// Create invalid key data (valid JSON but not a valid JWK)
+		invalidKeyData := []byte(`{"not": "a valid jwk"}`)
+
+		// Encrypt the invalid key data
+		encryptedData, err := cryptoutils.Encrypt(kek, invalidKeyData, nil)
+		require.NoError(t, err)
+
+		// Base64 encode the encrypted data
+		encodedData := base64.StdEncoding.EncodeToString(encryptedData)
+
+		// Save to database
+		err = db.Create(&model.KV{
+			Key:   PrivateKeyDBKey,
+			Value: &encodedData,
+		}).Error
+		require.NoError(t, err)
+
+		// Attempt to load the key
+		loadedKey, err := provider.LoadKey()
+		require.Error(t, err, "Expected error when loading invalid key data")
+		require.ErrorContains(t, err, "failed to parse")
+		assert.Nil(t, loadedKey, "Expected nil key when loading fails")
+	})
+}
+
+func TestKeyProviderDatabase_SaveKey(t *testing.T) {
+	// Generate a test key to use in our tests
+	pk, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	require.NoError(t, err)
+
+	key, err := jwk.Import(pk)
+	require.NoError(t, err)
+
+	t.Run("SaveKey and verify database record", func(t *testing.T) {
+		db := testutils.NewDatabaseForTest(t)
+		kek := generateTestKEK(t)
+
+		provider := &KeyProviderDatabase{}
+		err := provider.Init(KeyProviderOpts{
+			DB:  db,
+			Kek: kek,
+		})
+		require.NoError(t, err)
+
+		// Save the key
+		err = provider.SaveKey(key)
+		require.NoError(t, err, "Expected no error when saving key")
+
+		// Verify record exists in database
+		var kv model.KV
+		err = db.Where("key = ?", PrivateKeyDBKey).First(&kv).Error
+		require.NoError(t, err, "Expected to find key in database")
+		require.NotNil(t, kv.Value, "Expected non-nil value in database")
+		assert.NotEmpty(t, *kv.Value, "Expected non-empty value in database")
+
+		// Decode and decrypt to verify content
+		encBytes, err := base64.StdEncoding.DecodeString(*kv.Value)
+		require.NoError(t, err, "Expected valid base64 encoding")
+
+		decBytes, err := cryptoutils.Decrypt(kek, encBytes, nil)
+		require.NoError(t, err, "Expected valid encrypted data")
+
+		parsedKey, err := jwk.ParseKey(decBytes)
+		require.NoError(t, err, "Expected valid JWK data")
+
+		// Compare keys
+		keyBytes, err := EncodeJWKBytes(key)
+		require.NoError(t, err)
+
+		parsedKeyBytes, err := EncodeJWKBytes(parsedKey)
+		require.NoError(t, err)
+
+		assert.Equal(t, keyBytes, parsedKeyBytes, "Expected saved key to match original key")
+	})
+}
+
+func generateTestKEK(t *testing.T) []byte {
+	t.Helper()
+
+	// Generate a 32-byte kek
+	kek := make([]byte, 32)
+	_, err := rand.Read(kek)
+	require.NoError(t, err)
+	return kek
+}

backend/internal/utils/jwk/key_provider_file.go

@@ -0,0 +1,202 @@
+package jwk
+
+import (
+	"encoding/base64"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/lestrrat-go/jwx/v3/jwk"
+
+	"github.com/pocket-id/pocket-id/backend/internal/common"
+	"github.com/pocket-id/pocket-id/backend/internal/utils"
+	cryptoutils "github.com/pocket-id/pocket-id/backend/internal/utils/crypto"
+)
+
+const (
+	// PrivateKeyFile is the path in the data/keys folder where the key is stored
+	// This is a JSON file containing a key encoded as JWK
+	PrivateKeyFile = "jwt_private_key.json"
+
+	// PrivateKeyFileEncrypted is the path in the data/keys folder where the encrypted key is stored
+	// This is a encrypted JSON file containing a key encoded as JWK
+	PrivateKeyFileEncrypted = "jwt_private_key.json.enc"
+)
+
+type KeyProviderFile struct {
+	envConfig *common.EnvConfigSchema
+	kek       []byte
+}
+
+func (f *KeyProviderFile) Init(opts KeyProviderOpts) error {
+	f.envConfig = opts.EnvConfig
+	f.kek = opts.Kek
+
+	return nil
+}
+
+func (f *KeyProviderFile) LoadKey() (jwk.Key, error) {
+	if len(f.kek) > 0 {
+		return f.loadEncryptedKey()
+	}
+	return f.loadKey()
+}
+
+func (f *KeyProviderFile) SaveKey(key jwk.Key) error {
+	if len(f.kek) > 0 {
+		return f.saveKeyEncrypted(key)
+	}
+	return f.saveKey(key)
+}
+
+func (f *KeyProviderFile) loadKey() (jwk.Key, error) {
+	var key jwk.Key
+
+	// First, check if we have a JWK file
+	// If we do, then we just load that
+	jwkPath := f.jwkPath()
+	ok, err := utils.FileExists(jwkPath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to check if private key file exists at path '%s': %w", jwkPath, err)
+	}
+	if !ok {
+		// File doesn't exist, no key was loaded
+		return nil, nil
+	}
+
+	data, err := os.ReadFile(jwkPath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read private key file at path '%s': %w", jwkPath, err)
+	}
+
+	key, err = jwk.ParseKey(data)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse private key file at path '%s': %w", jwkPath, err)
+	}
+
+	return key, nil
+}
+
+func (f *KeyProviderFile) loadEncryptedKey() (key jwk.Key, err error) {
+	// First, check if we have an encrypted JWK file
+	// If we do, then we just load that
+	encJwkPath := f.encJwkPath()
+	ok, err := utils.FileExists(encJwkPath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to check if encrypted private key file exists at path '%s': %w", encJwkPath, err)
+	}
+	if ok {
+		encB64, err := os.ReadFile(encJwkPath)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read encrypted private key file at path '%s': %w", encJwkPath, err)
+		}
+
+		// Decode from base64
+		enc := make([]byte, base64.StdEncoding.DecodedLen(len(encB64)))
+		n, err := base64.StdEncoding.Decode(enc, encB64)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read encrypted private key file at path '%s': not a valid base64-encoded file: %w", encJwkPath, err)
+		}
+
+		// Decrypt the data
+		data, err := cryptoutils.Decrypt(f.kek, enc[:n], nil)
+		if err != nil {
+			return nil, fmt.Errorf("failed to decrypt private key file at path '%s': %w", encJwkPath, err)
+		}
+
+		// Parse the key
+		key, err = jwk.ParseKey(data)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse encrypted private key file at path '%s': %w", encJwkPath, err)
+		}
+
+		return key, nil
+	}
+
+	// Check if we have an un-encrypted JWK file
+	key, err = f.loadKey()
+	if err != nil {
+		return nil, fmt.Errorf("failed to load un-encrypted key file: %w", err)
+	}
+	if key == nil {
+		// No key exists, encrypted or un-encrypted
+		return nil, nil
+	}
+
+	// If we are here, we have loaded a key that was un-encrypted
+	// We need to replace the plaintext key with the encrypted one before we return
+	err = f.saveKeyEncrypted(key)
+	if err != nil {
+		return nil, fmt.Errorf("failed to save encrypted key file: %w", err)
+	}
+	jwkPath := f.jwkPath()
+	err = os.Remove(jwkPath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to remove un-encrypted key file at path '%s': %w", jwkPath, err)
+	}
+
+	return key, nil
+}
+
+func (f *KeyProviderFile) saveKey(key jwk.Key) error {
+	err := os.MkdirAll(f.envConfig.KeysPath, 0700)
+	if err != nil {
+		return fmt.Errorf("failed to create directory '%s' for key file: %w", f.envConfig.KeysPath, err)
+	}
+
+	jwkPath := f.jwkPath()
+	keyFile, err := os.OpenFile(jwkPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return fmt.Errorf("failed to create key file at path '%s': %w", jwkPath, err)
+	}
+	defer keyFile.Close()
+
+	// Write the JSON file to disk
+	err = EncodeJWK(keyFile, key)
+	if err != nil {
+		return fmt.Errorf("failed to write key file at path '%s': %w", jwkPath, err)
+	}
+
+	return nil
+}
+
+func (f *KeyProviderFile) saveKeyEncrypted(key jwk.Key) error {
+	err := os.MkdirAll(f.envConfig.KeysPath, 0700)
+	if err != nil {
+		return fmt.Errorf("failed to create directory '%s' for encrypted key file: %w", f.envConfig.KeysPath, err)
+	}
+
+	// Encode the key to JSON
+	data, err := EncodeJWKBytes(key)
+	if err != nil {
+		return fmt.Errorf("failed to encode key to JSON: %w", err)
+	}
+
+	// Encrypt the key then encode to Base64
+	enc, err := cryptoutils.Encrypt(f.kek, data, nil)
+	if err != nil {
+		return fmt.Errorf("failed to encrypt key: %w", err)
+	}
+	encB64 := make([]byte, base64.StdEncoding.EncodedLen(len(enc)))
+	base64.StdEncoding.Encode(encB64, enc)
+
+	// Write to disk
+	encJwkPath := f.encJwkPath()
+	err = os.WriteFile(encJwkPath, encB64, 0600)
+	if err != nil {
+		return fmt.Errorf("failed to write encrypted key file at path '%s': %w", encJwkPath, err)
+	}
+
+	return nil
+}
+
+func (f *KeyProviderFile) jwkPath() string {
+	return filepath.Join(f.envConfig.KeysPath, PrivateKeyFile)
+}
+
+func (f *KeyProviderFile) encJwkPath() string {
+	return filepath.Join(f.envConfig.KeysPath, PrivateKeyFileEncrypted)
+}
+
+// Compile-time interface check
+var _ KeyProvider = (*KeyProviderFile)(nil)

backend/internal/utils/jwk/key_provider_file_test.go

@@ -0,0 +1,320 @@
+package jwk
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"encoding/base64"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/lestrrat-go/jwx/v3/jwk"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/pocket-id/pocket-id/backend/internal/common"
+	"github.com/pocket-id/pocket-id/backend/internal/utils"
+	cryptoutils "github.com/pocket-id/pocket-id/backend/internal/utils/crypto"
+)
+
+func TestKeyProviderFile_LoadKey(t *testing.T) {
+	// Generate a test key to use in our tests
+	pk, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	require.NoError(t, err)
+
+	key, err := jwk.Import(pk)
+	require.NoError(t, err)
+
+	t.Run("LoadKey with no existing key", func(t *testing.T) {
+		tempDir := t.TempDir()
+
+		provider := &KeyProviderFile{}
+		err := provider.Init(KeyProviderOpts{
+			EnvConfig: &common.EnvConfigSchema{
+				KeysPath: tempDir,
+			},
+		})
+		require.NoError(t, err)
+
+		// Load key when none exists
+		loadedKey, err := provider.LoadKey()
+		require.NoError(t, err)
+		assert.Nil(t, loadedKey, "Expected nil key when no key exists")
+	})
+
+	t.Run("LoadKey with no existing key (with kek)", func(t *testing.T) {
+		tempDir := t.TempDir()
+
+		provider := &KeyProviderFile{}
+		err = provider.Init(KeyProviderOpts{
+			EnvConfig: &common.EnvConfigSchema{
+				KeysPath: tempDir,
+			},
+			Kek: makeKEK(t),
+		})
+		require.NoError(t, err)
+
+		// Load key when none exists
+		loadedKey, err := provider.LoadKey()
+		require.NoError(t, err)
+		assert.Nil(t, loadedKey, "Expected nil key when no key exists")
+	})
+
+	t.Run("LoadKey with unencrypted key", func(t *testing.T) {
+		tempDir := t.TempDir()
+
+		provider := &KeyProviderFile{}
+		err := provider.Init(KeyProviderOpts{
+			EnvConfig: &common.EnvConfigSchema{
+				KeysPath: tempDir,
+			},
+		})
+		require.NoError(t, err)
+
+		// Save a key
+		err = provider.SaveKey(key)
+		require.NoError(t, err)
+
+		// Make sure the key file exists
+		keyPath := filepath.Join(tempDir, PrivateKeyFile)
+		exists, err := utils.FileExists(keyPath)
+		require.NoError(t, err)
+		assert.True(t, exists, "Expected key file to exist")
+
+		// Load the key
+		loadedKey, err := provider.LoadKey()
+		require.NoError(t, err)
+		assert.NotNil(t, loadedKey, "Expected non-nil key when key exists")
+
+		// Verify the loaded key is the same as the original
+		keyBytes, err := EncodeJWKBytes(key)
+		require.NoError(t, err)
+
+		loadedKeyBytes, err := EncodeJWKBytes(loadedKey)
+		require.NoError(t, err)
+
+		assert.Equal(t, keyBytes, loadedKeyBytes, "Expected loaded key to match original key")
+	})
+
+	t.Run("LoadKey with encrypted key", func(t *testing.T) {
+		tempDir := t.TempDir()
+
+		provider := &KeyProviderFile{}
+		err = provider.Init(KeyProviderOpts{
+			EnvConfig: &common.EnvConfigSchema{
+				KeysPath: tempDir,
+			},
+			Kek: makeKEK(t),
+		})
+		require.NoError(t, err)
+
+		// Save a key (will be encrypted)
+		err = provider.SaveKey(key)
+		require.NoError(t, err)
+
+		// Make sure the encrypted key file exists
+		encKeyPath := filepath.Join(tempDir, PrivateKeyFileEncrypted)
+		exists, err := utils.FileExists(encKeyPath)
+		require.NoError(t, err)
+		assert.True(t, exists, "Expected encrypted key file to exist")
+
+		// Make sure the unencrypted key file does not exist
+		keyPath := filepath.Join(tempDir, PrivateKeyFile)
+		exists, err = utils.FileExists(keyPath)
+		require.NoError(t, err)
+		assert.False(t, exists, "Expected unencrypted key file to not exist")
+
+		// Load the key
+		loadedKey, err := provider.LoadKey()
+		require.NoError(t, err)
+		assert.NotNil(t, loadedKey, "Expected non-nil key when encrypted key exists")
+
+		// Verify the loaded key is the same as the original
+		keyBytes, err := EncodeJWKBytes(key)
+		require.NoError(t, err)
+
+		loadedKeyBytes, err := EncodeJWKBytes(loadedKey)
+		require.NoError(t, err)
+
+		assert.Equal(t, keyBytes, loadedKeyBytes, "Expected loaded key to match original key")
+	})
+
+	t.Run("LoadKey replaces unencrypted key with encrypted key when kek is provided", func(t *testing.T) {
+		tempDir := t.TempDir()
+
+		// First, create an unencrypted key
+		providerNoKek := &KeyProviderFile{}
+		err := providerNoKek.Init(KeyProviderOpts{
+			EnvConfig: &common.EnvConfigSchema{
+				KeysPath: tempDir,
+			},
+		})
+		require.NoError(t, err)
+
+		// Save an unencrypted key
+		err = providerNoKek.SaveKey(key)
+		require.NoError(t, err)
+
+		// Verify unencrypted key exists
+		keyPath := filepath.Join(tempDir, PrivateKeyFile)
+		exists, err := utils.FileExists(keyPath)
+		require.NoError(t, err)
+		assert.True(t, exists, "Expected unencrypted key file to exist")
+
+		// Now create a provider with a kek
+		kek := make([]byte, 32)
+		_, err = rand.Read(kek)
+		require.NoError(t, err)
+
+		providerWithKek := &KeyProviderFile{}
+		err = providerWithKek.Init(KeyProviderOpts{
+			EnvConfig: &common.EnvConfigSchema{
+				KeysPath: tempDir,
+			},
+			Kek: kek,
+		})
+		require.NoError(t, err)
+
+		// Load the key - this should convert the unencrypted key to encrypted
+		loadedKey, err := providerWithKek.LoadKey()
+		require.NoError(t, err)
+		assert.NotNil(t, loadedKey, "Expected non-nil key when loading and converting key")
+
+		// Verify the unencrypted key no longer exists
+		exists, err = utils.FileExists(keyPath)
+		require.NoError(t, err)
+		assert.False(t, exists, "Expected unencrypted key file to be removed")
+
+		// Verify the encrypted key file exists
+		encKeyPath := filepath.Join(tempDir, PrivateKeyFileEncrypted)
+		exists, err = utils.FileExists(encKeyPath)
+		require.NoError(t, err)
+		assert.True(t, exists, "Expected encrypted key file to exist after conversion")
+
+		// Verify the key data
+		keyBytes, err := EncodeJWKBytes(key)
+		require.NoError(t, err)
+
+		loadedKeyBytes, err := EncodeJWKBytes(loadedKey)
+		require.NoError(t, err)
+
+		assert.Equal(t, keyBytes, loadedKeyBytes, "Expected loaded key to match original key after conversion")
+	})
+}
+
+func TestKeyProviderFile_SaveKey(t *testing.T) {
+	// Generate a test key to use in our tests
+	pk, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	require.NoError(t, err)
+
+	key, err := jwk.Import(pk)
+	require.NoError(t, err)
+
+	t.Run("SaveKey unencrypted", func(t *testing.T) {
+		tempDir := t.TempDir()
+
+		provider := &KeyProviderFile{}
+		err := provider.Init(KeyProviderOpts{
+			EnvConfig: &common.EnvConfigSchema{
+				KeysPath: tempDir,
+			},
+		})
+		require.NoError(t, err)
+
+		// Save the key
+		err = provider.SaveKey(key)
+		require.NoError(t, err)
+
+		// Verify the key file exists
+		keyPath := filepath.Join(tempDir, PrivateKeyFile)
+		exists, err := utils.FileExists(keyPath)
+		require.NoError(t, err)
+		assert.True(t, exists, "Expected key file to exist")
+
+		// Verify the content of the key file
+		data, err := os.ReadFile(keyPath)
+		require.NoError(t, err)
+
+		parsedKey, err := jwk.ParseKey(data)
+		require.NoError(t, err)
+
+		// Compare the saved key with the original
+		keyBytes, err := EncodeJWKBytes(key)
+		require.NoError(t, err)
+
+		parsedKeyBytes, err := EncodeJWKBytes(parsedKey)
+		require.NoError(t, err)
+
+		assert.Equal(t, keyBytes, parsedKeyBytes, "Expected saved key to match original key")
+	})
+
+	t.Run("SaveKey encrypted", func(t *testing.T) {
+		tempDir := t.TempDir()
+
+		// Generate a 64-byte kek
+		kek := makeKEK(t)
+
+		provider := &KeyProviderFile{}
+		err = provider.Init(KeyProviderOpts{
+			EnvConfig: &common.EnvConfigSchema{
+				KeysPath: tempDir,
+			},
+			Kek: kek,
+		})
+		require.NoError(t, err)
+
+		// Save the key (will be encrypted)
+		err = provider.SaveKey(key)
+		require.NoError(t, err)
+
+		// Verify the encrypted key file exists
+		encKeyPath := filepath.Join(tempDir, PrivateKeyFileEncrypted)
+		exists, err := utils.FileExists(encKeyPath)
+		require.NoError(t, err)
+		assert.True(t, exists, "Expected encrypted key file to exist")
+
+		// Verify the unencrypted key file doesn't exist
+		keyPath := filepath.Join(tempDir, PrivateKeyFile)
+		exists, err = utils.FileExists(keyPath)
+		require.NoError(t, err)
+		assert.False(t, exists, "Expected unencrypted key file to not exist")
+
+		// Manually decrypt the encrypted key file to verify it contains the correct key
+		encB64, err := os.ReadFile(encKeyPath)
+		require.NoError(t, err)
+
+		// Decode from base64
+		enc := make([]byte, base64.StdEncoding.DecodedLen(len(encB64)))
+		n, err := base64.StdEncoding.Decode(enc, encB64)
+		require.NoError(t, err)
+		enc = enc[:n] // Trim any padding
+
+		// Decrypt the data
+		data, err := cryptoutils.Decrypt(kek, enc, nil)
+		require.NoError(t, err)
+
+		// Parse the key
+		parsedKey, err := jwk.ParseKey(data)
+		require.NoError(t, err)
+
+		// Compare the decrypted key with the original
+		keyBytes, err := EncodeJWKBytes(key)
+		require.NoError(t, err)
+
+		parsedKeyBytes, err := EncodeJWKBytes(parsedKey)
+		require.NoError(t, err)
+
+		assert.Equal(t, keyBytes, parsedKeyBytes, "Expected decrypted key to match original key")
+	})
+}
+
+func makeKEK(t *testing.T) []byte {
+	t.Helper()
+
+	// Generate a 32-byte kek
+	kek := make([]byte, 32)
+	_, err := rand.Read(kek)
+	require.NoError(t, err)
+	return kek
+}

backend/internal/utils/jwk/utils.go

@@ -0,0 +1,180 @@
+package jwk
+
+import (
+	"bytes"
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/elliptic"
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha3"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"hash"
+	"io"
+	"os"
+
+	"github.com/lestrrat-go/jwx/v3/jwa"
+	"github.com/lestrrat-go/jwx/v3/jwk"
+
+	"github.com/pocket-id/pocket-id/backend/internal/common"
+)
+
+const (
+	// KeyUsageSigning is the usage for the private keys, for the "use" property
+	KeyUsageSigning = "sig"
+)
+
+// EncodeJWK encodes a jwk.Key to a writable stream.
+func EncodeJWK(w io.Writer, key jwk.Key) error {
+	enc := json.NewEncoder(w)
+	enc.SetEscapeHTML(false)
+	return enc.Encode(key)
+}
+
+// EncodeJWKBytes encodes a jwk.Key to a byte slice.
+func EncodeJWKBytes(key jwk.Key) ([]byte, error) {
+	b := &bytes.Buffer{}
+	err := EncodeJWK(b, key)
+	if err != nil {
+		return nil, err
+	}
+	return b.Bytes(), nil
+}
+
+// LoadKeyEncryptionKey loads the key encryption key for JWKs
+func LoadKeyEncryptionKey(envConfig *common.EnvConfigSchema, instanceID string) (kek []byte, err error) {
+	// Try getting the key from the env var as string
+	kekInput := []byte(envConfig.EncryptionKey)
+
+	// If there's nothing in the env, try loading from file
+	if len(kekInput) == 0 && envConfig.EncryptionKeyFile != "" {
+		kekInput, err = os.ReadFile(envConfig.EncryptionKeyFile)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read key file '%s': %w", envConfig.EncryptionKeyFile, err)
+		}
+	}
+
+	// If there's still no key, return
+	if len(kekInput) == 0 {
+		return nil, nil
+	}
+
+	// We need a 256-bit key for encryption with AES-GCM-256
+	// We use HMAC with SHA3-256 here to derive the key from the one passed as input
+	// The key is tied to a specific instance of Pocket ID
+	h := hmac.New(func() hash.Hash { return sha3.New256() }, kekInput)
+	fmt.Fprint(h, "pocketid/"+instanceID+"/jwk-kek")
+	kek = h.Sum(nil)
+
+	return kek, nil
+}
+
+// ImportRawKey imports a crypto key in "raw" format (e.g. crypto.PrivateKey) into a jwk.Key.
+// It also populates additional fields such as the key ID, usage, and alg.
+func ImportRawKey(rawKey any, alg string, crv string) (jwk.Key, error) {
+	key, err := jwk.Import(rawKey)
+	if err != nil {
+		return nil, fmt.Errorf("failed to import generated private key: %w", err)
+	}
+
+	// Generate the key ID
+	kid, err := generateRandomKeyID()
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate key ID: %w", err)
+	}
+	_ = key.Set(jwk.KeyIDKey, kid)
+
+	// Set other required fields
+	_ = key.Set(jwk.KeyUsageKey, KeyUsageSigning)
+	EnsureAlgInKey(key, alg, crv)
+
+	return key, nil
+}
+
+// generateRandomKeyID generates a random key ID.
+func generateRandomKeyID() (string, error) {
+	buf := make([]byte, 8)
+	_, err := io.ReadFull(rand.Reader, buf)
+	if err != nil {
+		return "", fmt.Errorf("failed to read random bytes: %w", err)
+	}
+	return base64.RawURLEncoding.EncodeToString(buf), nil
+}
+
+// EnsureAlgInKey ensures that the key contains an "alg" parameter (and "crv", if needed), set depending on the key type
+func EnsureAlgInKey(key jwk.Key, alg string, crv string) {
+	_, ok := key.Algorithm()
+	if ok {
+		// Algorithm is already set
+		return
+	}
+
+	if alg != "" {
+		_ = key.Set(jwk.AlgorithmKey, alg)
+		if crv != "" {
+			eca, ok := jwa.LookupEllipticCurveAlgorithm(crv)
+			if ok {
+				switch key.KeyType() {
+				case jwa.EC():
+					_ = key.Set(jwk.ECDSACrvKey, eca)
+				case jwa.OKP():
+					_ = key.Set(jwk.OKPCrvKey, eca)
+				}
+			}
+		}
+		return
+	}
+
+	// If we don't have an algorithm, set the default for the key type
+	switch key.KeyType() {
+	case jwa.RSA():
+		// Default to RS256 for RSA keys
+		_ = key.Set(jwk.AlgorithmKey, jwa.RS256())
+	case jwa.EC():
+		// Default to ES256 for ECDSA keys
+		_ = key.Set(jwk.AlgorithmKey, jwa.ES256())
+		_ = key.Set(jwk.ECDSACrvKey, jwa.P256())
+	case jwa.OKP():
+		// Default to EdDSA and Ed25519 for OKP keys
+		_ = key.Set(jwk.AlgorithmKey, jwa.EdDSA())
+		_ = key.Set(jwk.OKPCrvKey, jwa.Ed25519())
+	}
+}
+
+// GenerateKey generates a new jwk.Key
+func GenerateKey(alg string, crv string) (key jwk.Key, err error) {
+	var rawKey any
+	switch alg {
+	case jwa.RS256().String():
+		rawKey, err = rsa.GenerateKey(rand.Reader, 2048)
+	case jwa.RS384().String():
+		rawKey, err = rsa.GenerateKey(rand.Reader, 3072)
+	case jwa.RS512().String():
+		rawKey, err = rsa.GenerateKey(rand.Reader, 4096)
+	case jwa.ES256().String():
+		rawKey, err = ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	case jwa.ES384().String():
+		rawKey, err = ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
+	case jwa.ES512().String():
+		rawKey, err = ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
+	case jwa.EdDSA().String():
+		switch crv {
+		case jwa.Ed25519().String():
+			_, rawKey, err = ed25519.GenerateKey(rand.Reader)
+		default:
+			return nil, errors.New("unsupported curve for EdDSA algorithm")
+		}
+	default:
+		return nil, errors.New("unsupported key algorithm")
+	}
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate private key: %w", err)
+	}
+
+	// Import the raw key
+	return ImportRawKey(rawKey, alg, crv)
+}

backend/internal/utils/jwk/utils_test.go

@@ -0,0 +1,324 @@
+package jwk
+
+import (
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"testing"
+
+	"github.com/lestrrat-go/jwx/v3/jwa"
+	"github.com/lestrrat-go/jwx/v3/jwk"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGenerateKey(t *testing.T) {
+	tests := []struct {
+		name        string
+		alg         string
+		crv         string
+		expectError bool
+		expectedAlg jwa.SignatureAlgorithm
+	}{
+		{
+			name:        "RS256",
+			alg:         jwa.RS256().String(),
+			crv:         "",
+			expectError: false,
+			expectedAlg: jwa.RS256(),
+		},
+		{
+			name:        "RS384",
+			alg:         jwa.RS384().String(),
+			crv:         "",
+			expectError: false,
+			expectedAlg: jwa.RS384(),
+		},
+		// Skip the RS512 test as generating a RSA-4096 key can take some time
+		/* {
+			name:        "RS512",
+			alg:         jwa.RS512().String(),
+			crv:         "",
+			expectError: false,
+			expectedAlg: jwa.RS512(),
+		}, */
+		{
+			name:        "ES256",
+			alg:         jwa.ES256().String(),
+			crv:         jwa.P256().String(),
+			expectError: false,
+			expectedAlg: jwa.ES256(),
+		},
+		{
+			name:        "ES384",
+			alg:         jwa.ES384().String(),
+			crv:         jwa.P384().String(),
+			expectError: false,
+			expectedAlg: jwa.ES384(),
+		},
+		{
+			name:        "ES512",
+			alg:         jwa.ES512().String(),
+			crv:         jwa.P521().String(),
+			expectError: false,
+			expectedAlg: jwa.ES512(),
+		},
+		{
+			name:        "EdDSA with Ed25519",
+			alg:         jwa.EdDSA().String(),
+			crv:         jwa.Ed25519().String(),
+			expectError: false,
+			expectedAlg: jwa.EdDSA(),
+		},
+		{
+			name:        "EdDSA with unsupported curve",
+			alg:         jwa.EdDSA().String(),
+			crv:         "unsupported",
+			expectError: true,
+		},
+		{
+			name:        "Unsupported algorithm",
+			alg:         "UNSUPPORTED",
+			crv:         "",
+			expectError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			key, err := GenerateKey(tt.alg, tt.crv)
+
+			if tt.expectError {
+				require.Error(t, err)
+				assert.Nil(t, key)
+				return
+			}
+
+			require.NoError(t, err)
+			require.NotNil(t, key)
+
+			// Verify the algorithm is set correctly
+			alg, ok := key.Algorithm()
+			require.True(t, ok, "algorithm should be set in the key")
+			assert.Equal(t, tt.expectedAlg.String(), alg.String())
+
+			// Verify other required fields are set
+			kid, ok := key.KeyID()
+			assert.True(t, ok, "key ID should be set")
+			assert.NotEmpty(t, kid, "key ID should not be empty")
+
+			usage, ok := key.KeyUsage()
+			assert.True(t, ok, "key usage should be set")
+			assert.Equal(t, KeyUsageSigning, usage)
+
+			var crv any
+			_ = key.Get("crv", &crv)
+
+			// Verify key type matches expected algorithm
+			switch tt.expectedAlg {
+			case jwa.RS256(), jwa.RS384(), jwa.RS512():
+				assert.Equal(t, jwa.RSA(), key.KeyType())
+				assert.Nil(t, crv)
+			case jwa.ES256(), jwa.ES384(), jwa.ES512():
+				assert.Equal(t, jwa.EC(), key.KeyType())
+				eca, ok := crv.(jwa.EllipticCurveAlgorithm)
+				_ = assert.NotNil(t, crv) &&
+					assert.True(t, ok) &&
+					assert.Equal(t, tt.crv, eca.String())
+			case jwa.EdDSA():
+				assert.Equal(t, jwa.OKP(), key.KeyType())
+				eca, ok := crv.(jwa.EllipticCurveAlgorithm)
+				_ = assert.NotNil(t, crv) &&
+					assert.True(t, ok) &&
+					assert.Equal(t, tt.crv, eca.String())
+			}
+		})
+	}
+}
+
+func TestEnsureAlgInKey(t *testing.T) {
+	// Generate an RSA-2048 key
+	rsaKey, err := rsa.GenerateKey(rand.Reader, 2048)
+	require.NoError(t, err)
+
+	t.Run("does not change alg already set", func(t *testing.T) {
+		// Import the RSA key
+		key, err := jwk.Import(rsaKey)
+		require.NoError(t, err)
+
+		// Pre-set the algorithm
+		_ = key.Set(jwk.AlgorithmKey, jwa.RS256())
+
+		// Call EnsureAlgInKey with a different algorithm
+		EnsureAlgInKey(key, jwa.RS384().String(), "")
+
+		// Verify the algorithm wasn't changed
+		alg, ok := key.Algorithm()
+		require.True(t, ok)
+		assert.Equal(t, jwa.RS256().String(), alg.String())
+	})
+
+	t.Run("set algorithm to explicitly-provided value", func(t *testing.T) {
+		tests := []struct {
+			name        string
+			keyGen      func() (any, error)
+			alg         string
+			crv         string
+			expectedAlg jwa.SignatureAlgorithm
+			expectedCrv string
+		}{
+			{
+				name: "RSA key with RS384",
+				keyGen: func() (any, error) {
+					return rsaKey, nil
+				},
+				alg:         jwa.RS384().String(),
+				crv:         "",
+				expectedAlg: jwa.RS384(),
+				expectedCrv: "",
+			},
+			{
+				name: "ECDSA key with ES384",
+				keyGen: func() (any, error) {
+					return ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+				},
+				alg:         jwa.ES384().String(),
+				crv:         jwa.P384().String(),
+				expectedAlg: jwa.ES384(),
+				expectedCrv: jwa.P384().String(),
+			},
+			{
+				name: "Ed25519 key with EdDSA",
+				keyGen: func() (any, error) {
+					_, priv, err := ed25519.GenerateKey(rand.Reader)
+					return priv, err
+				},
+				alg:         jwa.EdDSA().String(),
+				crv:         jwa.Ed25519().String(),
+				expectedAlg: jwa.EdDSA(),
+				expectedCrv: jwa.Ed25519().String(),
+			},
+		}
+
+		for _, tt := range tests {
+			t.Run(tt.name, func(t *testing.T) {
+				rawKey, err := tt.keyGen()
+				require.NoError(t, err)
+
+				key, err := jwk.Import(rawKey)
+				require.NoError(t, err)
+
+				// Ensure no algorithm is set initially
+				_, ok := key.Algorithm()
+				assert.False(t, ok)
+
+				// Call EnsureAlgInKey
+				EnsureAlgInKey(key, tt.alg, tt.crv)
+
+				// Verify the algorithm was set correctly
+				alg, ok := key.Algorithm()
+				require.True(t, ok)
+				assert.Equal(t, tt.expectedAlg.String(), alg.String())
+
+				// Verify curve if expected
+				if tt.expectedCrv != "" {
+					var crv any
+					_ = key.Get("crv", &crv)
+					require.NotNil(t, crv)
+					eca, ok := crv.(jwa.EllipticCurveAlgorithm)
+					require.True(t, ok)
+					assert.Equal(t, tt.expectedCrv, eca.String())
+				}
+			})
+		}
+	})
+
+	t.Run("set default algorithms if not present", func(t *testing.T) {
+		tests := []struct {
+			name        string
+			keyGen      func() (any, error)
+			expectedAlg jwa.SignatureAlgorithm
+			expectedCrv string
+		}{
+			{
+				name: "RSA key defaults to RS256",
+				keyGen: func() (any, error) {
+					return rsaKey, nil
+				},
+				expectedAlg: jwa.RS256(),
+				expectedCrv: "",
+			},
+			{
+				name: "ECDSA key defaults to ES256 with P256",
+				keyGen: func() (any, error) {
+					return ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+				},
+				expectedAlg: jwa.ES256(),
+				expectedCrv: jwa.P256().String(),
+			},
+			{
+				name: "Ed25519 key defaults to EdDSA with Ed25519",
+				keyGen: func() (any, error) {
+					_, priv, err := ed25519.GenerateKey(rand.Reader)
+					return priv, err
+				},
+				expectedAlg: jwa.EdDSA(),
+				expectedCrv: jwa.Ed25519().String(),
+			},
+		}
+
+		for _, tt := range tests {
+			t.Run(tt.name, func(t *testing.T) {
+				rawKey, err := tt.keyGen()
+				require.NoError(t, err)
+
+				key, err := jwk.Import(rawKey)
+				require.NoError(t, err)
+
+				// Ensure no algorithm is set initially
+				_, ok := key.Algorithm()
+				assert.False(t, ok)
+
+				// Call EnsureAlgInKey with empty parameters
+				EnsureAlgInKey(key, "", "")
+
+				// Verify the default algorithm was set
+				alg, ok := key.Algorithm()
+				require.True(t, ok)
+				assert.Equal(t, tt.expectedAlg.String(), alg.String())
+
+				// Verify curve if expected
+				if tt.expectedCrv != "" {
+					var crv any
+					_ = key.Get("crv", &crv)
+					require.NotNil(t, crv)
+					eca, ok := crv.(jwa.EllipticCurveAlgorithm)
+					require.True(t, ok)
+					assert.Equal(t, tt.expectedCrv, eca.String())
+				}
+			})
+		}
+	})
+
+	t.Run("invalid curve should not set curve parameter", func(t *testing.T) {
+		rsaKey, err := rsa.GenerateKey(rand.Reader, 2048)
+		require.NoError(t, err)
+
+		key, err := jwk.Import(rsaKey)
+		require.NoError(t, err)
+
+		// Call EnsureAlgInKey with invalid curve
+		EnsureAlgInKey(key, jwa.RS256().String(), "invalid-curve")
+
+		// Verify algorithm was set but curve was not
+		alg, ok := key.Algorithm()
+		require.True(t, ok)
+		assert.Equal(t, jwa.RS256().String(), alg.String())
+
+		var crv any
+		_ = key.Get("crv", &crv)
+		assert.Nil(t, crv)
+	})
+}

backend/internal/utils/jwk_util.go

@@ -1,69 +0,0 @@
-package utils
-
-import (
-	"crypto/rand"
-	"encoding/base64"
-	"fmt"
-	"io"
-
-	"github.com/lestrrat-go/jwx/v3/jwa"
-	"github.com/lestrrat-go/jwx/v3/jwk"
-)
-
-const (
-	// KeyUsageSigning is the usage for the private keys, for the "use" property
-	KeyUsageSigning = "sig"
-)
-
-// ImportRawKey imports a crypto key in "raw" format (e.g. crypto.PrivateKey) into a jwk.Key.
-// It also populates additional fields such as the key ID, usage, and alg.
-func ImportRawKey(rawKey any) (jwk.Key, error) {
-	key, err := jwk.Import(rawKey)
-	if err != nil {
-		return nil, fmt.Errorf("failed to import generated private key: %w", err)
-	}
-
-	// Generate the key ID
-	kid, err := generateRandomKeyID()
-	if err != nil {
-		return nil, fmt.Errorf("failed to generate key ID: %w", err)
-	}
-	_ = key.Set(jwk.KeyIDKey, kid)
-
-	// Set other required fields
-	_ = key.Set(jwk.KeyUsageKey, KeyUsageSigning)
-	EnsureAlgInKey(key)
-
-	return key, nil
-}
-
-// generateRandomKeyID generates a random key ID.
-func generateRandomKeyID() (string, error) {
-	buf := make([]byte, 8)
-	_, err := io.ReadFull(rand.Reader, buf)
-	if err != nil {
-		return "", fmt.Errorf("failed to read random bytes: %w", err)
-	}
-	return base64.RawURLEncoding.EncodeToString(buf), nil
-}
-
-// EnsureAlgInKey ensures that the key contains an "alg" parameter, set depending on the key type
-func EnsureAlgInKey(key jwk.Key) {
-	_, ok := key.Algorithm()
-	if ok {
-		// Algorithm is already set
-		return
-	}
-
-	switch key.KeyType() {
-	case jwa.RSA():
-		// Default to RS256 for RSA keys
-		_ = key.Set(jwk.AlgorithmKey, jwa.RS256())
-	case jwa.EC():
-		// Default to ES256 for ECDSA keys
-		_ = key.Set(jwk.AlgorithmKey, jwa.ES256())
-	case jwa.OKP():
-		// Default to EdDSA for OKP keys
-		_ = key.Set(jwk.AlgorithmKey, jwa.EdDSA())
-	}
-}

backend/internal/utils/testing/database.go

@@ -1,9 +1,8 @@
-package service
+// This file is only imported by unit tests
+
+package testing
 
 import (
-	"io"
-	"net/http"
-	"strings"
 	"testing"
 	"time"
 
@@ -21,7 +20,10 @@ import (
 	"github.com/pocket-id/pocket-id/backend/resources"
 )
 
-func newDatabaseForTest(t *testing.T) *gorm.DB {
+// NewDatabaseForTest returns a new instance of GORM connected to an in-memory SQLite database.
+// Each database connection is unique for the test.
+// All migrations are automatically performed.
+func NewDatabaseForTest(t *testing.T) *gorm.DB {
 	t.Helper()
 
 	// Get a name for this in-memory database that is specific to the test
@@ -68,30 +70,3 @@ type testLoggerAdapter struct {
 func (l testLoggerAdapter) Printf(format string, args ...any) {
 	l.t.Logf(format, args...)
 }
-
-// MockRoundTripper is a custom http.RoundTripper that returns responses based on the URL
-type MockRoundTripper struct {
-	Err       error
-	Responses map[string]*http.Response
-}
-
-// RoundTrip implements the http.RoundTripper interface
-func (m *MockRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
-	// Check if we have a specific response for this URL
-	for url, resp := range m.Responses {
-		if req.URL.String() == url {
-			return resp, nil
-		}
-	}
-
-	return NewMockResponse(http.StatusNotFound, ""), nil
-}
-
-// NewMockResponse creates an http.Response with the given status code and body
-func NewMockResponse(statusCode int, body string) *http.Response {
-	return &http.Response{
-		StatusCode: statusCode,
-		Body:       io.NopCloser(strings.NewReader(body)),
-		Header:     make(http.Header),
-	}
-}

backend/internal/utils/testing/round_tripper.go

@@ -0,0 +1,38 @@
+// This file is only imported by unit tests
+
+package testing
+
+import (
+	"io"
+	"net/http"
+	"strings"
+
+	_ "github.com/golang-migrate/migrate/v4/source/file"
+)
+
+// MockRoundTripper is a custom http.RoundTripper that returns responses based on the URL
+type MockRoundTripper struct {
+	Err       error
+	Responses map[string]*http.Response
+}
+
+// RoundTrip implements the http.RoundTripper interface
+func (m *MockRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	// Check if we have a specific response for this URL
+	for url, resp := range m.Responses {
+		if req.URL.String() == url {
+			return resp, nil
+		}
+	}
+
+	return NewMockResponse(http.StatusNotFound, ""), nil
+}
+
+// NewMockResponse creates an http.Response with the given status code and body
+func NewMockResponse(statusCode int, body string) *http.Response {
+	return &http.Response{
+		StatusCode: statusCode,
+		Body:       io.NopCloser(strings.NewReader(body)),
+		Header:     make(http.Header),
+	}
+}

backend/resources/migrations/postgres/20250630000000_kv_table.down.sql

@@ -0,0 +1 @@
+DROP TABLE kv;

backend/resources/migrations/postgres/20250630000000_kv_table.up.sql

@@ -0,0 +1,6 @@
+-- The "kv" tables contains miscellaneous key-value pairs
+CREATE TABLE kv
+(
+    "key"  TEXT NOT NULL PRIMARY KEY,
+    "value" TEXT
+);

backend/resources/migrations/sqlite/20250630000000_kv_table.down.sql

@@ -0,0 +1 @@
+DROP TABLE kv;

backend/resources/migrations/sqlite/20250630000000_kv_table.up.sql

@@ -0,0 +1,6 @@
+-- The "kv" tables contains miscellaneous key-value pairs
+CREATE TABLE kv
+(
+    "key"  TEXT NOT NULL PRIMARY KEY,
+    "value" TEXT NOT NULL
+);