Added test for AuthenticationFailedException during filename decryption

main/filesystem-crypto/src/main/java/org/cryptomator/crypto/engine/AuthenticationFailedException.java

@@ -0,0 +1,17 @@
+/*******************************************************************************
+ * Copyright (c) 2016 Sebastian Stenzel and others.
+ * This file is licensed under the terms of the MIT license.
+ * See the LICENSE.txt file for more info.
+ *
+ * Contributors:
+ *     Sebastian Stenzel - initial API and implementation
+ *******************************************************************************/
+package org.cryptomator.crypto.engine;
+
+public class AuthenticationFailedException extends CryptoException {
+
+	public AuthenticationFailedException(String message, Throwable cause) {
+		super(message, cause);
+	}
+
+}

main/filesystem-crypto/src/main/java/org/cryptomator/crypto/engine/CryptoException.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2015 Sebastian Stenzel and others.
+ * Copyright (c) 2016 Sebastian Stenzel and others.
  * This file is licensed under the terms of the MIT license.
  * See the LICENSE.txt file for more info.
  *
@@ -8,11 +8,7 @@
  *******************************************************************************/
 package org.cryptomator.crypto.engine;
 
-import java.io.IOException;
-
-public class CryptoException extends IOException {
-
-	private static final long serialVersionUID = -6536997506620449023L;
+abstract class CryptoException extends RuntimeException {
 
 	public CryptoException(String message, Throwable cause) {
 		super(message, cause);

main/filesystem-crypto/src/main/java/org/cryptomator/crypto/engine/impl/FifoParallelDataProcessor.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2015 Sebastian Stenzel and others.
+ * Copyright (c) 2015, 2016 Sebastian Stenzel and others.
  * This file is licensed under the terms of the MIT license.
  * See the LICENSE.txt file for more info.
  *

main/filesystem-crypto/src/main/java/org/cryptomator/crypto/engine/impl/FilenameCryptorImpl.java

@@ -8,7 +8,6 @@
  *******************************************************************************/
 package org.cryptomator.crypto.engine.impl;
 
-import java.io.UncheckedIOException;
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
@@ -18,7 +17,7 @@ import javax.crypto.SecretKey;
 
 import org.apache.commons.codec.binary.Base32;
 import org.apache.commons.codec.binary.BaseNCodec;
-import org.cryptomator.crypto.engine.CryptoException;
+import org.cryptomator.crypto.engine.AuthenticationFailedException;
 import org.cryptomator.crypto.engine.FilenameCryptor;
 import org.cryptomator.siv.SivMode;
 
@@ -58,7 +57,7 @@ class FilenameCryptorImpl implements FilenameCryptor {
 			final byte[] cleartextBytes = AES_SIV.decrypt(encryptionKey, macKey, encryptedBytes);
 			return new String(cleartextBytes, StandardCharsets.UTF_8);
 		} catch (AEADBadTagException e) {
-			throw new UncheckedIOException(new CryptoException("Authentication failed.", e));
+			throw new AuthenticationFailedException("Authentication failed.", e);
 		}
 	}
 

main/filesystem-crypto/src/test/java/org/cryptomator/crypto/engine/impl/FifoParallelDataProcessorTest.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2015 Sebastian Stenzel and others.
+ * Copyright (c) 2015, 2016 Sebastian Stenzel and others.
  * This file is licensed under the terms of the MIT license.
  * See the LICENSE.txt file for more info.
  *

main/filesystem-crypto/src/test/java/org/cryptomator/crypto/engine/impl/FileContentCryptorTest.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2015 Sebastian Stenzel and others.
+ * Copyright (c) 2015, 2016 Sebastian Stenzel and others.
  * This file is licensed under the terms of the MIT license.
  * See the LICENSE.txt file for more info.
  *

main/filesystem-crypto/src/test/java/org/cryptomator/crypto/engine/impl/FilenameCryptorImplTest.java

@@ -9,11 +9,13 @@
 package org.cryptomator.crypto.engine.impl;
 
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.util.UUID;
 
 import javax.crypto.SecretKey;
 import javax.crypto.spec.SecretKeySpec;
 
+import org.cryptomator.crypto.engine.AuthenticationFailedException;
 import org.cryptomator.crypto.engine.FilenameCryptor;
 import org.junit.Assert;
 import org.junit.Test;
@@ -62,4 +64,16 @@ public class FilenameCryptorImplTest {
 		}
 	}
 
+	@Test(expected = AuthenticationFailedException.class)
+	public void testDecryptionOfManipulatedFilename() {
+		final byte[] keyBytes = new byte[32];
+		final SecretKey encryptionKey = new SecretKeySpec(keyBytes, "AES");
+		final SecretKey macKey = new SecretKeySpec(keyBytes, "AES");
+		final FilenameCryptor filenameCryptor = new FilenameCryptorImpl(encryptionKey, macKey);
+
+		final byte[] encrypted = filenameCryptor.encryptFilename("test").getBytes(StandardCharsets.UTF_8);
+		encrypted[0] ^= (byte) 0x01; // change 1 bit in first byte
+		filenameCryptor.decryptFilename(new String(encrypted, StandardCharsets.UTF_8));
+	}
+
 }