refactor(security): migrate from jws to jwe

Signed-off-by: Alan Brault <alan.brault@visus.io>

.env.example

@@ -12,12 +12,12 @@
 MONGODB_URI=mongodb://localhost:27017/kotlin-api
 
 # ════════════════════════════════════════════════════════════════════════════════
-# JWT Security Configuration
+# JWT Security Configuration (JWE - JSON Web Encryption)
 # ════════════════════════════════════════════════════════════════════════════════
-# REQUIRED: Generate a secure base64-encoded secret for JWT token signing
-# MUST be base64-encoded (your code uses Decoders.BASE64.decode)
+# REQUIRED: Generate a secure base64-encoded secret for JWT token encryption
+# MUST be exactly 32 bytes when base64-decoded (for AES-256-GCM encryption)
 #
-# Generate a secure base64-encoded secret (single line, no newlines):
-#   openssl rand -base64 64 | tr -d '\n'
+# Generate a secure 32-byte base64-encoded encryption secret (single line, no newlines):
+#   openssl rand -base64 32 | tr -d '\n'
 #
-JWT_SECRET=your-base64-encoded-secret-here
+JWT_ENCRYPTION_SECRET=your-base64-encoded-32-byte-secret-here

src/main/kotlin/io/visus/demos/kotlinapi/config/JwtProperties.kt

@@ -6,7 +6,7 @@ import org.springframework.stereotype.Component
 @Component
 @ConfigurationProperties("jwt")
 data class JwtProperties(
-    var secret: String = "",
+    var encryptionSecret: String = "",
     var accessTokenExpiration: Long = 3600000, // 1 hour
     var refreshTokenExpiration: Long = 2592000000, // 30 days
     var issuer: String = "kotlin-api",

src/main/kotlin/io/visus/demos/kotlinapi/infrastructure/security/JwtTokenProvider.kt

@@ -7,16 +7,15 @@ import io.jsonwebtoken.Jwts
 import io.jsonwebtoken.MalformedJwtException
 import io.jsonwebtoken.UnsupportedJwtException
 import io.jsonwebtoken.io.Decoders
-import io.jsonwebtoken.security.Keys
 import io.visus.demos.kotlinapi.config.JwtProperties
 import io.visus.demos.kotlinapi.domain.model.JwtTokenType
 import org.slf4j.LoggerFactory
 import org.springframework.security.core.userdetails.UserDetails
 import org.springframework.stereotype.Component
-import java.security.SignatureException
 import java.util.Date
 import java.util.UUID
 import javax.crypto.SecretKey
+import javax.crypto.spec.SecretKeySpec
 
 @Component
 class JwtTokenProvider(
@@ -24,9 +23,9 @@ class JwtTokenProvider(
 ) {
     private val logger = LoggerFactory.getLogger(JwtTokenProvider::class.java)
 
-    private val secretKey: SecretKey by lazy {
-        val bytes = Decoders.BASE64.decode(jwtProperties.secret)
-        Keys.hmacShaKeyFor(bytes)
+    private val encryptionKey: SecretKey by lazy {
+        val bytes = Decoders.BASE64.decode(jwtProperties.encryptionSecret)
+        SecretKeySpec(bytes, "AES")
     }
 
     fun <T> extractClaim(
@@ -36,9 +35,9 @@ class JwtTokenProvider(
         val claims =
             Jwts
                 .parser()
-                .verifyWith(secretKey)
+                .decryptWith(encryptionKey)
                 .build()
-                .parseSignedClaims(token)
+                .parseEncryptedClaims(token)
                 .payload
 
         return claimsResolver(claims)
@@ -76,7 +75,7 @@ class JwtTokenProvider(
             ).issuedAt(now)
             .expiration(expiry)
             .issuer(jwtProperties.issuer)
-            .signWith(secretKey, Jwts.SIG.HS512)
+            .encryptWith(encryptionKey, Jwts.KEY.DIRECT, Jwts.ENC.A256GCM)
             .compact()
     }
 
@@ -95,7 +94,7 @@ class JwtTokenProvider(
                     .toString(), // UUIDv7
             ).issuedAt(now)
             .expiration(expiry)
-            .signWith(secretKey, Jwts.SIG.HS512)
+            .encryptWith(encryptionKey, Jwts.KEY.DIRECT, Jwts.ENC.A256GCM)
             .compact()
     }
 
@@ -122,13 +121,11 @@ class JwtTokenProvider(
         try {
             Jwts
                 .parser()
-                .verifyWith(secretKey)
+                .decryptWith(encryptionKey)
                 .build()
-                .parseSignedClaims(token)
+                .parseEncryptedClaims(token)
 
             return true
-        } catch (ex: SignatureException) {
-            logger.error("Invalid JWT signature: {}", ex.message)
         } catch (ex: MalformedJwtException) {
             logger.error("Invalid JWT token: {}", ex.message)
         } catch (ex: ExpiredJwtException) {

src/main/resources/application.yaml

@@ -8,7 +8,7 @@ spring:
     uri: ${MONGODB_URI:mongodb://localhost:27017/kotlin-api}
 
 jwt:
-  secret: ${JWT_SECRET}
+  encryption-secret: ${JWT_ENCRYPTION_SECRET}
   access-token-expiration: 3600000 # 1 hour in milliseconds
   refresh-token-expiration: 2592000000 # 30 days in milliseconds
   issuer: kotlin-api