- report authentication error on the UI

- reduced visibility of some classes

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

@@ -28,7 +28,6 @@ import javax.crypto.SecretKey;
 import javax.crypto.ShortBufferException;
 import javax.crypto.spec.IvParameterSpec;
 
-import org.apache.commons.codec.binary.Hex;
 import org.cryptomator.crypto.engine.FileContentCryptor;
 import org.cryptomator.crypto.engine.FileContentEncryptor;
 import org.cryptomator.io.ByteBuffers;
@@ -165,7 +164,6 @@ class FileContentEncryptorImpl implements FileContentEncryptor {
 				mac.update(nonce);
 				mac.update(ciphertextBuf);
 				byte[] authenticationCode = mac.doFinal();
-				Hex.encodeHexString(authenticationCode);
 				outBuf.put(authenticationCode);
 
 				// flip and return:

main/filesystem-crypto/src/main/java/org/cryptomator/filesystem/crypto/CryptoFile.java

@@ -35,7 +35,11 @@ public class CryptoFile extends CryptoNode implements File {
 	@Override
 	public ReadableFile openReadable() {
 		boolean authenticate = !fileSystem().delegate().shouldSkipAuthentication(toString());
-		return new CryptoReadableFile(cryptor.getFileContentCryptor(), forceGetPhysicalFile().openReadable(), authenticate);
+		return new CryptoReadableFile(cryptor.getFileContentCryptor(), forceGetPhysicalFile().openReadable(), authenticate, this::reportAuthError);
+	}
+
+	private void reportAuthError() {
+		fileSystem().delegate().authenticationFailed(this.toString());
 	}
 
 	@Override

main/filesystem-crypto/src/main/java/org/cryptomator/filesystem/crypto/CryptoReadableFile.java

@@ -8,6 +8,7 @@
  *******************************************************************************/
 package org.cryptomator.filesystem.crypto;
 
+import java.io.IOException;
 import java.io.InterruptedIOException;
 import java.io.UncheckedIOException;
 import java.nio.ByteBuffer;
@@ -15,6 +16,7 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
 
+import org.cryptomator.crypto.engine.AuthenticationFailedException;
 import org.cryptomator.crypto.engine.FileContentCryptor;
 import org.cryptomator.crypto.engine.FileContentDecryptor;
 import org.cryptomator.filesystem.ReadableFile;
@@ -29,15 +31,17 @@ class CryptoReadableFile implements ReadableFile {
 	private final FileContentCryptor cryptor;
 	private final ReadableFile file;
 	private final boolean authenticate;
+	private final Runnable onAuthError;
 	private FileContentDecryptor decryptor;
 	private Future<Void> readAheadTask;
 	private ByteBuffer bufferedCleartext = EMPTY_BUFFER;
 
-	public CryptoReadableFile(FileContentCryptor cryptor, ReadableFile file, boolean authenticate) {
+	public CryptoReadableFile(FileContentCryptor cryptor, ReadableFile file, boolean authenticate, Runnable onAuthError) {
 		this.header = ByteBuffer.allocate(cryptor.getHeaderSize());
 		this.cryptor = cryptor;
 		this.file = file;
 		this.authenticate = authenticate;
+		this.onAuthError = onAuthError;
 		file.position(0);
 		file.read(header);
 		header.flip();
@@ -58,6 +62,8 @@ class CryptoReadableFile implements ReadableFile {
 			return bytesRead;
 		} catch (InterruptedException e) {
 			throw new UncheckedIOException(new InterruptedIOException("Task interrupted while waiting for cleartext"));
+		} catch (IOException e) {
+			throw new UncheckedIOException(e);
 		}
 	}
 
@@ -78,9 +84,14 @@ class CryptoReadableFile implements ReadableFile {
 		readAheadTask = executorService.submit(new CiphertextReader(file, decryptor, header.remaining() + ciphertextPos));
 	}
 
-	private void bufferCleartext() throws InterruptedException {
+	private void bufferCleartext() throws InterruptedException, IOException {
 		if (!bufferedCleartext.hasRemaining()) {
-			bufferedCleartext = decryptor.cleartext();
+			try {
+				bufferedCleartext = decryptor.cleartext();
+			} catch (AuthenticationFailedException e) {
+				onAuthError.run();
+				throw new IOException("Failed to decrypt file due to an authentication error.", e);
+			}
 		}
 	}
 

main/filesystem-crypto/src/test/java/org/cryptomator/filesystem/crypto/CryptoReadableFileTest.java

@@ -37,8 +37,11 @@ public class CryptoReadableFileTest {
 			}
 		}).thenThrow(new UncheckedIOException(new IOException("failed.")));
 
+		Runnable noop = () -> {
+		};
+
 		@SuppressWarnings("resource")
-		ReadableFile cryptoReadableFile = new CryptoReadableFile(fileContentCryptor, underlyingFile, true);
+		ReadableFile cryptoReadableFile = new CryptoReadableFile(fileContentCryptor, underlyingFile, true, noop);
 		cryptoReadableFile.read(ByteBuffer.allocate(1));
 	}