diff --git a/src/main/java/com/trilead/ssh2/auth/AuthenticationManager.java b/src/main/java/com/trilead/ssh2/auth/AuthenticationManager.java
index 76410cfb..71c51163 100644
--- a/src/main/java/com/trilead/ssh2/auth/AuthenticationManager.java
+++ b/src/main/java/com/trilead/ssh2/auth/AuthenticationManager.java
@@ -317,34 +317,11 @@ else if (publicKey instanceof ECPublicKey)
 
 				tm.sendMessage(ua.getPayload());
 			}
-			else if (PublicKeyUtils.isEd25519Key(publicKey))
-			{
-				final String algo = Ed25519Verify.ED25519_ID;
-
-				byte[] pk_enc = Ed25519Verify.get().encodePublicKey(publicKey);
-
-				byte[] msg = this.generatePublicKeyUserAuthenticationRequest(user, algo, pk_enc);
-
-				byte[] ed_sig_enc;
-				if (signatureProxy != null)
-				{
-					ed_sig_enc = signatureProxy.sign(msg, SignatureProxy.SHA512);
-				}
-				else
-				{
-					Ed25519PrivateKey pk = Ed25519Verify.convertPrivateKey(privateKey);
-					ed_sig_enc = Ed25519Verify.get().generateSignature(msg, pk, rnd);
-				}
-
-				PacketUserauthRequestPublicKey ua = new PacketUserauthRequestPublicKey("ssh-connection", user,
-						algo, pk_enc, ed_sig_enc);
-
-				tm.sendMessage(ua.getPayload());
-			}
 			else if (publicKey instanceof SkPublicKey)
 			{
 				// FIDO2 Security Key (SK) authentication
-				// SK keys require external signing via SignatureProxy
+				// This check must come before the Ed25519 check because
+				// SK Ed25519 keys match isEd25519Key() but require SK-specific encoding.
 				if (signatureProxy == null)
 				{
 					throw new IOException("SK key authentication requires a SignatureProxy for signing.");
@@ -380,6 +357,30 @@ else if (publicKey instanceof SkPublicKey)
 
 				tm.sendMessage(ua.getPayload());
 			}
+			else if (PublicKeyUtils.isEd25519Key(publicKey))
+			{
+				final String algo = Ed25519Verify.ED25519_ID;
+
+				byte[] pk_enc = Ed25519Verify.get().encodePublicKey(publicKey);
+
+				byte[] msg = this.generatePublicKeyUserAuthenticationRequest(user, algo, pk_enc);
+
+				byte[] ed_sig_enc;
+				if (signatureProxy != null)
+				{
+					ed_sig_enc = signatureProxy.sign(msg, SignatureProxy.SHA512);
+				}
+				else
+				{
+					Ed25519PrivateKey pk = Ed25519Verify.convertPrivateKey(privateKey);
+					ed_sig_enc = Ed25519Verify.get().generateSignature(msg, pk, rnd);
+				}
+
+				PacketUserauthRequestPublicKey ua = new PacketUserauthRequestPublicKey("ssh-connection", user,
+						algo, pk_enc, ed_sig_enc);
+
+				tm.sendMessage(ua.getPayload());
+			}
 			else
 			{
 				throw new IOException("Unknown public key type.");
diff --git a/src/test/java/com/trilead/ssh2/auth/AuthenticationManagerSkKeyTest.java b/src/test/java/com/trilead/ssh2/auth/AuthenticationManagerSkKeyTest.java
index 89003091..7e15469d 100644
--- a/src/test/java/com/trilead/ssh2/auth/AuthenticationManagerSkKeyTest.java
+++ b/src/test/java/com/trilead/ssh2/auth/AuthenticationManagerSkKeyTest.java
@@ -53,11 +53,17 @@ public class AuthenticationManagerSkKeyTest {
 	 */
 	static class TestSkPublicKey implements SkPublicKey {
 		private final String keyType;
+		private final String algorithm;
 		private final String application;
 		private final byte[] keyData;
 
 		TestSkPublicKey(String keyType, String application, byte[] keyData) {
+			this(keyType, keyType, application, keyData);
+		}
+
+		TestSkPublicKey(String keyType, String algorithm, String application, byte[] keyData) {
 			this.keyType = keyType;
+			this.algorithm = algorithm;
 			this.application = application;
 			this.keyData = keyData.clone();
 		}
@@ -79,7 +85,7 @@ public byte[] getKeyData() {
 
 		@Override
 		public String getAlgorithm() {
-			return keyType;
+			return algorithm;
 		}
 
 		@Override
@@ -238,6 +244,45 @@ public void authenticateSkKey_SendsAuthenticationRequest() throws Exception {
 			"Authentication should send at least one message");
 	}
 
+	/**
+	 * Regression test: SK Ed25519 key with "Ed25519" algorithm must use the SK
+	 * code path, not the generic Ed25519 path. The real SkEd25519PublicKey returns
+	 * "Ed25519" from getAlgorithm(), which matches isEd25519Key(). Without the
+	 * fix, this causes Ed25519Verify.encodePublicKey() to attempt DER decoding
+	 * and fail with InvalidKeySpecException.
+	 */
+	@Test
+	public void authenticateSkEd25519Key_WithEd25519Algorithm_UsesSkPath() throws Exception {
+		TestSkPublicKey skKey = new TestSkPublicKey(SK_ED25519_KEY_TYPE, "Ed25519", DEFAULT_APPLICATION, TEST_KEY_DATA);
+		TestSignatureProxy signatureProxy = new TestSignatureProxy(skKey, TEST_SIGNATURE);
+
+		setupMocksForAuthentication();
+		setupMockForAuthSuccess();
+
+		authManager.authenticatePublicKey(TEST_USER, signatureProxy);
+
+		assertEquals(SignatureProxy.SHA512, signatureProxy.getLastHashAlgorithm(),
+			"SK Ed25519 key with Ed25519 algorithm should use SK path with SHA512");
+	}
+
+	/**
+	 * Regression test: SK ECDSA key with "EC" algorithm must use the SK
+	 * code path, not the generic ECDSA path.
+	 */
+	@Test
+	public void authenticateSkEcdsaKey_WithEcAlgorithm_UsesSkPath() throws Exception {
+		TestSkPublicKey skKey = new TestSkPublicKey(SK_ECDSA_KEY_TYPE, "EC", DEFAULT_APPLICATION, TEST_KEY_DATA);
+		TestSignatureProxy signatureProxy = new TestSignatureProxy(skKey, TEST_SIGNATURE);
+
+		setupMocksForAuthentication();
+		setupMockForAuthSuccess();
+
+		authManager.authenticatePublicKey(TEST_USER, signatureProxy);
+
+		assertEquals(SignatureProxy.SHA256, signatureProxy.getLastHashAlgorithm(),
+			"SK ECDSA key with EC algorithm should use SK path with SHA256");
+	}
+
 	private void setupMocksForAuthentication() throws IOException {
 		lenient().when(tm.getSessionIdentifier()).thenReturn(TEST_SESSION_ID);
 		lenient().when(tm.getExtensionInfo()).thenReturn(extensionInfo);