Changed from JWT token to public/privat key

readme.md

@@ -87,7 +87,7 @@ Tracking known work that is not yet implemented. Each item is independently acti
 
 ### Security
 
-- **Switch JWT signing from HS256 → EdDSA (Ed25519).** Today Auth and Core share a symmetric `JWT_SECRET`, which means a Core compromise lets an attacker forge tokens. Move to an asymmetric keypair: Auth holds the private key and signs, Core only holds the public key and verifies. `jjwt 0.13` supports this via `Jwts.SIG.EdDSA`; JDK 25 has native `Ed25519` `KeyFactory`. Touches `JwtService`, `JwtConfig`, `application.yml`, `JwtServiceTest`, and the deployment env vars (`JWT_PRIVATE_KEY`, `JWT_PUBLIC_KEY` replace `JWT_SECRET`). Add a `kid` header so future rotation is possible.
+- ~~**Switch JWT signing from HS256 → EdDSA (Ed25519).**~~ Done. Auth signs with an Ed25519 private key (`JWT_PRIVATE_KEY`), Core verifies with the matching public key (`JWT_PUBLIC_KEY`). `kid` header (`JWT_KID`) is emitted to support future rotation. See `JwtService`, `JwtConfig`, `application.yml`, `JwtServiceTest`, and `ToBePlayed-Deployment/README.md` for the rollout / rotation procedure.
 - **Refresh-token rotation.** Current access tokens last 24h with no revocation path. Split into a short-lived (5–15 min) access token and a long-lived (7–30 day) refresh token, rotated on every use, persisted server-side so logout / password change / "log out everywhere" actually revoke. Add a `token_version` column on `users` (or a `jti` blacklist table) checked on each refresh.
 - **Move JWT delivery to an httpOnly `Secure` cookie.** Tokens are currently returned in the response body and stored by the frontend in `localStorage`, exposing them to any XSS payload. Set the cookie server-side, scope it to `.tbp.andreas-dahm.eu`, and add CSRF protection (Spring Security's `CookieCsrfTokenRepository.withHttpOnlyFalse()`).
 - **Tighten CORS for cookie auth.** Restrict allowed origins to `https://tbp.andreas-dahm.eu` (plus the local dev origin) and set `allowCredentials=true`. Required before switching to cookie-based JWT.

src/main/java/auth_service/configuration/security/JwtConfig.java

@@ -11,5 +11,12 @@ import org.springframework.context.annotation.Configuration;
 @ConfigurationProperties(prefix = "security.jwt")
 public class JwtConfig {
 
-    private String secret;
+    /** Base64-encoded PKCS8 DER Ed25519 private key. Used to sign JWTs. */
+    private String privateKey;
+
+    /** Base64-encoded X.509 DER Ed25519 public key. Embedded so JWKS can publish it. */
+    private String publicKey;
+
+    /** Key identifier set in the JWS `kid` header. Enables future rotation. */
+    private String kid;
 }

src/main/java/auth_service/configuration/security/JwtService.java

@@ -2,35 +2,46 @@ package auth_service.configuration.security;
 
 import auth_service.modules.login.service.TokenGenerator;
 import io.jsonwebtoken.Jwts;
-import io.jsonwebtoken.security.Keys;
+import jakarta.annotation.PostConstruct;
 import org.springframework.stereotype.Service;
 
-import javax.crypto.SecretKey;
+import java.security.KeyFactory;
-import java.nio.charset.StandardCharsets;
+import java.security.PrivateKey;
+import java.security.PublicKey;
+import java.security.spec.PKCS8EncodedKeySpec;
+import java.security.spec.X509EncodedKeySpec;
+import java.util.Base64;
 import java.util.Date;
 
 /**
  * Service responsible for generating and validating JSON Web Tokens (JWT).
+ * Signing: EdDSA (Ed25519). Auth holds the private key and signs; Core holds only the public key and verifies.
  */
 @Service
 public class JwtService implements TokenGenerator {
 
     // Token validity: 24 hours in milliseconds
     private static final long JWT_EXPIRATION_MS = 86400000;
+    private static final String ED25519 = "Ed25519";
+
     private final JwtConfig jwtConfig;
+    private PrivateKey privateKey;
+    private PublicKey publicKey;
 
     public JwtService(JwtConfig jwtConfig) {
         this.jwtConfig = jwtConfig;
     }
 
-    /**
+    @PostConstruct
-     * Generates a secure JWT for the authenticated user.
+    void init() {
-     *
+        this.privateKey = decodePrivateKey(jwtConfig.getPrivateKey());
-     * @return A signed JWT string
+        this.publicKey = decodePublicKey(jwtConfig.getPublicKey());
-     */
+    }
+
     @Override
     public String generateToken(String userId, String email, Long steamId) {
         var builder = Jwts.builder()
+                .header().keyId(jwtConfig.getKid()).and()
                 .subject(email)
                 .claim("userId", userId)
                 .issuedAt(new Date(System.currentTimeMillis()))
@@ -41,13 +52,13 @@ public class JwtService implements TokenGenerator {
         }
 
         return builder
-                .signWith(getSigningKey())
+                .signWith(privateKey, Jwts.SIG.EdDSA)
                 .compact();
     }
 
     public String extractEmail(String token) {
         return Jwts.parser()
-                .verifyWith(getSigningKey())
+                .verifyWith(publicKey)
                 .build()
                 .parseSignedClaims(token)
                 .getPayload()
@@ -56,7 +67,7 @@ public class JwtService implements TokenGenerator {
 
     public String extractUserId(String token) {
         return Jwts.parser()
-                .verifyWith(getSigningKey())
+                .verifyWith(publicKey)
                 .build()
                 .parseSignedClaims(token)
                 .getPayload()
@@ -65,7 +76,7 @@ public class JwtService implements TokenGenerator {
 
     public Long extractSteamId(String token) {
         return Jwts.parser()
-                .verifyWith(getSigningKey())
+                .verifyWith(publicKey)
                 .build()
                 .parseSignedClaims(token)
                 .getPayload()
@@ -75,7 +86,7 @@ public class JwtService implements TokenGenerator {
     public boolean isTokenValid(String token) {
         try {
             Jwts.parser()
-                    .verifyWith(getSigningKey())
+                    .verifyWith(publicKey)
                     .build()
                     .parseSignedClaims(token);
             return true;
@@ -84,12 +95,21 @@ public class JwtService implements TokenGenerator {
         }
     }
 
-    /**
+    private static PrivateKey decodePrivateKey(String base64Pkcs8Der) {
-     * Retrieves the cryptographic key used for signing the token.
+        try {
-     */
+            byte[] keyBytes = Base64.getDecoder().decode(base64Pkcs8Der);
-    private SecretKey getSigningKey() {
+            return KeyFactory.getInstance(ED25519).generatePrivate(new PKCS8EncodedKeySpec(keyBytes));
-        String secretKey = jwtConfig.getSecret();
+        } catch (Exception e) {
-        byte[] keyBytes = secretKey.getBytes(StandardCharsets.UTF_8);
+            throw new IllegalStateException("Failed to decode Ed25519 private key", e);
-        return Keys.hmacShaKeyFor(keyBytes);
+        }
+    }
+
+    private static PublicKey decodePublicKey(String base64X509Der) {
+        try {
+            byte[] keyBytes = Base64.getDecoder().decode(base64X509Der);
+            return KeyFactory.getInstance(ED25519).generatePublic(new X509EncodedKeySpec(keyBytes));
+        } catch (Exception e) {
+            throw new IllegalStateException("Failed to decode Ed25519 public key", e);
+        }
     }
 }

src/main/resources/application.yml

@@ -44,7 +44,9 @@ management:
 # Security stuff
 security:
   jwt:
-    secret: ${JWT_SECRET}
+    private-key: ${JWT_PRIVATE_KEY}
+    public-key: ${JWT_PUBLIC_KEY}
+    kid: ${JWT_KID:tbp-auth-1}
 
 # Custom properties for CORS
 app:

src/test/java/auth_service/configuration/security/JwtServiceTest.java

@@ -1,109 +1,109 @@
 package auth_service.configuration.security;
 
 import auth_service.shared.test.AbstractUnitTest;
+import io.jsonwebtoken.Jwts;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.mockito.Mock;
 
-import static org.junit.jupiter.api.Assertions.*;
+import java.security.KeyFactory;
-import static org.mockito.Mockito.when;
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+import java.security.PublicKey;
+import java.security.spec.X509EncodedKeySpec;
+import java.util.Base64;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.lenient;
 
 /**
- * Tests for JwtService.
+ * Tests for JwtService (EdDSA / Ed25519).
  */
 class JwtServiceTest extends AbstractUnitTest {
 
+    private static final String KID = "test-key-1";
+
     @Mock
     private JwtConfig jwtConfig;
 
     private JwtService jwtService;
+    private PublicKey publicKey;
 
     @BeforeEach
-    void setUp() {
+    void setUp() throws Exception {
-        when(jwtConfig.getSecret()).thenReturn("verysecretkeythatmustbeatleast32characterslongforhmacsha");
+        KeyPair keyPair = KeyPairGenerator.getInstance("Ed25519").generateKeyPair();
+        String privateB64 = Base64.getEncoder().encodeToString(keyPair.getPrivate().getEncoded());
+        String publicB64 = Base64.getEncoder().encodeToString(keyPair.getPublic().getEncoded());
+
+        lenient().when(jwtConfig.getPrivateKey()).thenReturn(privateB64);
+        lenient().when(jwtConfig.getPublicKey()).thenReturn(publicB64);
+        lenient().when(jwtConfig.getKid()).thenReturn(KID);
+
+        publicKey = KeyFactory.getInstance("Ed25519")
+                .generatePublic(new X509EncodedKeySpec(Base64.getDecoder().decode(publicB64)));
+
         jwtService = new JwtService(jwtConfig);
+        jwtService.init();
     }
 
     @Test
     void generateToken_Success() {
-        // Arrange
+        var token = jwtService.generateToken("0815", "test@example.com", null);
-        var userId = "0815";
-        var email = "test@example.com";
 
-        // Act
-        var token = jwtService.generateToken(userId, email, null);
-
-        // Assert
         assertNotNull(token);
         assertFalse(token.isEmpty());
     }
 
+    @Test
+    void generateToken_setsKidHeader() {
+        var token = jwtService.generateToken("0815", "test@example.com", null);
+
+        var header = Jwts.parser()
+                .verifyWith(publicKey)
+                .build()
+                .parseSignedClaims(token)
+                .getHeader();
+
+        assertEquals(KID, header.getKeyId());
+        assertEquals("EdDSA", header.getAlgorithm());
+    }
+
     @Test
     void extractEmail_Success() {
-        // Arrange
-        var userId = "0815";
         var email = "test@example.com";
-        var token = jwtService.generateToken(userId, email, null);
+        var token = jwtService.generateToken("0815", email, null);
 
-        // Act
+        assertEquals(email, jwtService.extractEmail(token));
-        var extractedEmail = jwtService.extractEmail(token);
-
-        // Assert
-        assertEquals(email, extractedEmail);
     }
 
     @Test
     void extractUserId_Success() {
-        // Arrange
         var userId = "0815";
-        var email = "test@example.com";
+        var token = jwtService.generateToken(userId, "test@example.com", null);
-        var token = jwtService.generateToken(userId, email, null);
 
-        // Act
+        assertEquals(userId, jwtService.extractUserId(token));
-        var extractedUserId = jwtService.extractUserId(token);
-
-        // Assert
-        assertEquals(userId, extractedUserId);
     }
 
     @Test
     void extractSteamId_Success() {
-        // Arrange
-        var userId = "0815";
-        var email = "test@example.com";
         var steamId = 123456789L;
-        var token = jwtService.generateToken(userId, email, steamId);
+        var token = jwtService.generateToken("0815", "test@example.com", steamId);
 
-        // Act
+        assertEquals(steamId, jwtService.extractSteamId(token));
-        var extractedSteamId = jwtService.extractSteamId(token);
-
-        // Assert
-        assertEquals(steamId, extractedSteamId);
     }
 
     @Test
     void isTokenValid_Success() {
-        // Arrange
+        var token = jwtService.generateToken("0815", "test@example.com", null);
-        var userId = "0815";
-        var email = "test@example.com";
-        var token = jwtService.generateToken(userId, email, null);
 
-        // Act
+        assertTrue(jwtService.isTokenValid(token));
-        var isValid = jwtService.isTokenValid(token);
-
-        // Assert
-        assertTrue(isValid);
     }
 
     @Test
     void isTokenValid_Failure() {
-        // Arrange
+        assertFalse(jwtService.isTokenValid("invalid-token"));
-        var invalidToken = "invalid-token";
-
-        // Act
-        var isValid = jwtService.isTokenValid(invalidToken);
-
-        // Assert
-        assertFalse(isValid);
     }
 }