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authenticated file header

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This commit is contained in:
Sebastian Stenzel 2015-05-04 21:31:41 +02:00
parent cdf9c28a38
commit 040f260bf0
5 changed files with 171 additions and 126 deletions
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3
main/core/src/main/java/org/cryptomator/webdav/jackrabbit/EncryptedFile.java
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@ -107,6 +107,9 @@ class EncryptedFile extends AbstractEncryptedNode {
} catch (IOException e) {
LOG.error("Error reading filesize " + path.toString(), e);
throw new IORuntimeException(e);
} catch (MacAuthenticationFailedException e) {
LOG.warn("Content length couldn't be determined due to MAC authentication violation.");
// don't add content length DAV property
}
try {

258
main/crypto-aes/src/main/java/org/cryptomator/crypto/aes256/Aes256Cryptor.java
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@ -60,8 +60,8 @@ import com.fasterxml.jackson.databind.ObjectMapper;
public class Aes256Cryptor implements Cryptor, AesCryptographicConfiguration, FileNamingConventions {
/**
* Defined in static initializer. Defaults to 256, but falls back to maximum value possible, if JCE Unlimited Strength Jurisdiction
* Policy Files isn't installed. Those files can be downloaded here: http://www.oracle.com/technetwork/java/javase/downloads/.
* Defined in static initializer. Defaults to 256, but falls back to maximum value possible, if JCE Unlimited Strength Jurisdiction Policy Files isn't installed. Those files can be downloaded
* here: http://www.oracle.com/technetwork/java/javase/downloads/.
*/
private static final int AES_KEY_LENGTH_IN_BITS;
@ -78,8 +78,8 @@ public class Aes256Cryptor implements Cryptor, AesCryptographicConfiguration, Fi
private final ObjectMapper objectMapper = new ObjectMapper();
/**
* The decrypted master key. Its lifecycle starts with the construction of an Aes256Cryptor instance or
* {@link #decryptMasterKey(InputStream, CharSequence)}. Its lifecycle ends with {@link #swipeSensitiveData()}.
* The decrypted master key. Its lifecycle starts with the construction of an Aes256Cryptor instance or {@link #decryptMasterKey(InputStream, CharSequence)}. Its lifecycle ends with
* {@link #swipeSensitiveData()}.
*/
private SecretKey primaryMasterKey;
@ -149,10 +149,8 @@ public class Aes256Cryptor implements Cryptor, AesCryptographicConfiguration, Fi
* Reads the encrypted masterkey from the given input stream and decrypts it with the given password.
*
* @throws DecryptFailedException If the decryption failed for various reasons (including wrong password).
* @throws WrongPasswordException If the provided password was wrong. Note: Sometimes the algorithm itself fails due to a wrong
* password. In this case a DecryptFailedException will be thrown.
* @throws UnsupportedKeyLengthException If the masterkey has been encrypted with a higher key length than supported by the system. In
* this case Java JCE needs to be installed.
* @throws WrongPasswordException If the provided password was wrong. Note: Sometimes the algorithm itself fails due to a wrong password. In this case a DecryptFailedException will be thrown.
* @throws UnsupportedKeyLengthException If the masterkey has been encrypted with a higher key length than supported by the system. In this case Java JCE needs to be installed.
*/
@Override
public void decryptMasterKey(InputStream in, CharSequence password) throws DecryptFailedException, WrongPasswordException, UnsupportedKeyLengthException, IOException {
@ -293,18 +291,14 @@ public class Aes256Cryptor implements Cryptor, AesCryptographicConfiguration, Fi
/**
* Each path component, i.e. file or directory name separated by path separators, gets encrypted for its own.<br/>
* Encryption will blow up the filename length due to aes block sizes and base32 encoding. The result may be too long for some old file
* systems.<br/>
* This means that we need a workaround for filenames longer than the limit defined in
* {@link FileNamingConventions#ENCRYPTED_FILENAME_LENGTH_LIMIT}.<br/>
* Encryption will blow up the filename length due to aes block sizes and base32 encoding. The result may be too long for some old file systems.<br/>
* This means that we need a workaround for filenames longer than the limit defined in {@link FileNamingConventions#ENCRYPTED_FILENAME_LENGTH_LIMIT}.<br/>
* <br/>
* In any case we will create the encrypted filename normally. For those, that are too long, we calculate a checksum. No
* cryptographically secure hash is needed here. We just want an uniform distribution for better load balancing. All encrypted filenames
* with the same checksum will then share a metadata file, in which a lookup map between encrypted filenames and short unique
* In any case we will create the encrypted filename normally. For those, that are too long, we calculate a checksum. No cryptographically secure hash is needed here. We just want an uniform
* distribution for better load balancing. All encrypted filenames with the same checksum will then share a metadata file, in which a lookup map between encrypted filenames and short unique
* alternative names are stored.<br/>
* <br/>
* These alternative names consist of the checksum, a unique id and a special file extension defined in
* {@link FileNamingConventions#LONG_NAME_FILE_EXT}.
* These alternative names consist of the checksum, a unique id and a special file extension defined in {@link FileNamingConventions#LONG_NAME_FILE_EXT}.
*/
@Override
public String encryptFilename(String cleartextName, CryptorMetadataSupport ioSupport) throws IOException {
@ -361,23 +355,65 @@ public class Aes256Cryptor implements Cryptor, AesCryptographicConfiguration, Fi
}
@Override
public Long decryptedContentLength(SeekableByteChannel encryptedFile) throws IOException {
// skip 128bit IV + 256 bit MAC:
encryptedFile.position(48);
// read encrypted value:
final ByteBuffer encryptedFileSizeBuffer = ByteBuffer.allocate(AES_BLOCK_LENGTH);
final int numFileSizeBytesRead = encryptedFile.read(encryptedFileSizeBuffer);
// return "unknown" value, if EOF
if (numFileSizeBytesRead != encryptedFileSizeBuffer.capacity()) {
public Long decryptedContentLength(SeekableByteChannel encryptedFile) throws IOException, MacAuthenticationFailedException {
// read header:
encryptedFile.position(0);
final ByteBuffer headerBuf = ByteBuffer.allocate(64);
final int headerBytesRead = encryptedFile.read(headerBuf);
if (headerBytesRead != headerBuf.capacity()) {
return null;
}
// decrypt size:
// read content length:
headerBuf.position(16);
final byte[] encryptedContentLengthBytes = new byte[AES_BLOCK_LENGTH];
headerBuf.get(encryptedContentLengthBytes);
final Long fileSize = decryptContentLength(encryptedContentLengthBytes);
// read stored header mac:
headerBuf.position(32);
final byte[] storedHeaderMac = new byte[32];
headerBuf.get(storedHeaderMac);
// calculate mac over first 32 bytes of header:
final Mac headerMac = this.hmacSha256(hMacMasterKey);
headerBuf.rewind();
headerBuf.limit(32);
headerMac.update(headerBuf);
final boolean macMatches = MessageDigest.isEqual(storedHeaderMac, headerMac.doFinal());
if (!macMatches) {
throw new MacAuthenticationFailedException("MAC authentication failed.");
}
return fileSize;
}
// private void encryptedContentLength(SeekableByteChannel encryptedFile, Long contentLength) throws IOException {
// final ByteBuffer encryptedFileSizeBuffer;
//
// // encrypt content length in ECB mode (content length is less than one block):
// try {
// final ByteBuffer fileSizeBuffer = ByteBuffer.allocate(Long.BYTES);
// fileSizeBuffer.putLong(contentLength);
// final Cipher sizeCipher = aesEcbCipher(primaryMasterKey, Cipher.ENCRYPT_MODE);
// final byte[] encryptedFileSize = sizeCipher.doFinal(fileSizeBuffer.array());
// encryptedFileSizeBuffer = ByteBuffer.wrap(encryptedFileSize);
// } catch (IllegalBlockSizeException | BadPaddingException e) {
// throw new IllegalStateException("Block size must be valid, as padding is requested. BadPaddingException not possible in encrypt mode.", e);
// }
//
// // skip 128bit IV:
// encryptedFile.position(16l);
//
// // write result:
// encryptedFile.write(encryptedFileSizeBuffer);
// }
private long decryptContentLength(byte[] encryptedContentLengthBytes) {
try {
final Cipher sizeCipher = aesEcbCipher(primaryMasterKey, Cipher.DECRYPT_MODE);
final byte[] decryptedFileSize = sizeCipher.doFinal(encryptedFileSizeBuffer.array());
final byte[] decryptedFileSize = sizeCipher.doFinal(encryptedContentLengthBytes);
final ByteBuffer fileSizeBuffer = ByteBuffer.wrap(decryptedFileSize);
return fileSizeBuffer.getLong();
} catch (IllegalBlockSizeException | BadPaddingException e) {
@ -385,85 +421,90 @@ public class Aes256Cryptor implements Cryptor, AesCryptographicConfiguration, Fi
}
}
private void encryptedContentLength(SeekableByteChannel encryptedFile, Long contentLength) throws IOException {
final ByteBuffer encryptedFileSizeBuffer;
// encrypt content length in ECB mode (content length is less than one block):
private byte[] encryptContentLength(long contentLength) {
try {
final ByteBuffer fileSizeBuffer = ByteBuffer.allocate(Long.BYTES);
fileSizeBuffer.putLong(contentLength);
final Cipher sizeCipher = aesEcbCipher(primaryMasterKey, Cipher.ENCRYPT_MODE);
final byte[] encryptedFileSize = sizeCipher.doFinal(fileSizeBuffer.array());
encryptedFileSizeBuffer = ByteBuffer.wrap(encryptedFileSize);
return sizeCipher.doFinal(fileSizeBuffer.array());
} catch (IllegalBlockSizeException | BadPaddingException e) {
throw new IllegalStateException("Block size must be valid, as padding is requested. BadPaddingException not possible in encrypt mode.", e);
}
// skip 128bit IV + 256 bit MAC:
encryptedFile.position(48);
// write result:
encryptedFile.write(encryptedFileSizeBuffer);
}
@Override
public boolean isAuthentic(SeekableByteChannel encryptedFile) throws IOException {
// init mac:
final Mac calculatedMac = this.hmacSha256(hMacMasterKey);
// read stored mac:
encryptedFile.position(16);
final ByteBuffer storedMac = ByteBuffer.allocate(calculatedMac.getMacLength());
final int numMacBytesRead = encryptedFile.read(storedMac);
// check validity of header:
if (numMacBytesRead != calculatedMac.getMacLength()) {
// read header:
encryptedFile.position(0);
final ByteBuffer headerBuf = ByteBuffer.allocate(96);
final int headerBytesRead = encryptedFile.read(headerBuf);
if (headerBytesRead != headerBuf.capacity()) {
throw new IOException("Failed to read file header.");
}
// go to begin of content:
encryptedFile.position(64);
// read header mac:
headerBuf.position(32);
final byte[] storedHeaderMac = new byte[32];
headerBuf.get(storedHeaderMac);
// calculated MAC
// read content mac:
headerBuf.position(64);
final byte[] storedContentMac = new byte[32];
headerBuf.get(storedContentMac);
// calculate mac over first 32 bytes of header:
final Mac headerMac = this.hmacSha256(hMacMasterKey);
headerBuf.rewind();
headerBuf.limit(32);
headerMac.update(headerBuf);
// calculate mac over content:
encryptedFile.position(96);
final Mac contentMac = this.hmacSha256(hMacMasterKey);
final InputStream in = new SeekableByteChannelInputStream(encryptedFile);
final InputStream macIn = new MacInputStream(in, calculatedMac);
final InputStream macIn = new MacInputStream(in, contentMac);
IOUtils.copyLarge(macIn, new NullOutputStream());
// compare (in constant time):
return MessageDigest.isEqual(storedMac.array(), calculatedMac.doFinal());
final boolean headerMacMatches = MessageDigest.isEqual(storedHeaderMac, headerMac.doFinal());
final boolean contentMacMatches = MessageDigest.isEqual(storedContentMac, contentMac.doFinal());
return headerMacMatches && contentMacMatches;
}
@Override
public Long decryptFile(SeekableByteChannel encryptedFile, OutputStream plaintextFile) throws IOException, DecryptFailedException {
// read iv:
// read header:
encryptedFile.position(0);
final ByteBuffer countingIv = ByteBuffer.allocate(AES_BLOCK_LENGTH);
final int numIvBytesRead = encryptedFile.read(countingIv);
// init mac:
final Mac calculatedMac = this.hmacSha256(hMacMasterKey);
// read stored mac:
final ByteBuffer storedMac = ByteBuffer.allocate(calculatedMac.getMacLength());
final int numMacBytesRead = encryptedFile.read(storedMac);
// read file size:
final Long fileSize = decryptedContentLength(encryptedFile);
// check validity of header:
if (numIvBytesRead != AES_BLOCK_LENGTH || numMacBytesRead != calculatedMac.getMacLength() || fileSize == null) {
final ByteBuffer headerBuf = ByteBuffer.allocate(96);
final int headerBytesRead = encryptedFile.read(headerBuf);
if (headerBytesRead != headerBuf.capacity()) {
throw new IOException("Failed to read file header.");
}
headerBuf.rewind();
// go to begin of content:
encryptedFile.position(64);
// read iv:
final byte[] iv = new byte[AES_BLOCK_LENGTH];
headerBuf.get(iv);
// generate cipher:
final Cipher cipher = this.aesCtrCipher(primaryMasterKey, countingIv.array(), Cipher.DECRYPT_MODE);
// read content length:
final byte[] encryptedContentLengthBytes = new byte[AES_BLOCK_LENGTH];
headerBuf.get(encryptedContentLengthBytes);
final Long fileSize = decryptContentLength(encryptedContentLengthBytes);
// read content
// read header mac:
final byte[] headerMac = new byte[32];
headerBuf.get(headerMac);
// read content mac:
final byte[] contentMac = new byte[32];
headerBuf.get(contentMac);
// decrypt content
encryptedFile.position(96l);
final Mac calculatedContentMac = this.hmacSha256(hMacMasterKey);
final Cipher cipher = this.aesCtrCipher(primaryMasterKey, iv, Cipher.DECRYPT_MODE);
final InputStream in = new SeekableByteChannelInputStream(encryptedFile);
final InputStream macIn = new MacInputStream(in, calculatedMac);
final InputStream macIn = new MacInputStream(in, calculatedContentMac);
final InputStream cipheredIn = new CipherInputStream(macIn, cipher);
final long bytesDecrypted = IOUtils.copyLarge(cipheredIn, plaintextFile, 0, fileSize);
@ -471,7 +512,7 @@ public class Aes256Cryptor implements Cryptor, AesCryptographicConfiguration, Fi
IOUtils.copyLarge(macIn, new NullOutputStream());
// compare (in constant time):
final boolean macMatches = MessageDigest.isEqual(storedMac.array(), calculatedMac.doFinal());
final boolean macMatches = MessageDigest.isEqual(contentMac, calculatedContentMac.doFinal());
if (!macMatches) {
// This exception will be thrown AFTER we sent the decrypted content to the user.
// This has two advantages:
@ -503,7 +544,7 @@ public class Aes256Cryptor implements Cryptor, AesCryptographicConfiguration, Fi
countingIv.putInt(AES_BLOCK_LENGTH - Integer.BYTES, (int) firstRelevantBlock); // int-cast is possible, as max file size is 64GiB
// fast forward stream:
encryptedFile.position(64l + beginOfFirstRelevantBlock);
encryptedFile.position(96l + beginOfFirstRelevantBlock);
// generate cipher:
final Cipher cipher = this.aesCtrCipher(primaryMasterKey, countingIv.array(), Cipher.DECRYPT_MODE);
@ -514,30 +555,30 @@ public class Aes256Cryptor implements Cryptor, AesCryptographicConfiguration, Fi
return IOUtils.copyLarge(cipheredIn, plaintextFile, offsetInsideFirstRelevantBlock, length);
}
/**
* header = {16 byte iv, 16 byte filesize, 32 byte headerMac, 32 byte contentMac}
*/
@Override
public Long encryptFile(InputStream plaintextFile, SeekableByteChannel encryptedFile) throws IOException, EncryptFailedException {
// truncate file
encryptedFile.truncate(0);
// 96 byte header buffer (16 IV, 16 size, 32 headerMac, 32 contentMac):
final ByteBuffer headerBuf = ByteBuffer.allocate(96);
encryptedFile.write(headerBuf);
// use an IV, whose last 8 bytes store a long used in counter mode and write initial value to file.
final ByteBuffer countingIv = ByteBuffer.wrap(randomData(AES_BLOCK_LENGTH));
countingIv.putInt(AES_BLOCK_LENGTH - Integer.BYTES, 0);
encryptedFile.write(countingIv);
// init crypto stuff:
final Mac mac = this.hmacSha256(hMacMasterKey);
final Cipher cipher = this.aesCtrCipher(primaryMasterKey, countingIv.array(), Cipher.ENCRYPT_MODE);
// init mac buffer and skip 32 bytes
final ByteBuffer macBuffer = ByteBuffer.allocate(mac.getMacLength());
encryptedFile.write(macBuffer);
final ByteBuffer iv = ByteBuffer.wrap(randomData(AES_BLOCK_LENGTH));
iv.putInt(AES_BLOCK_LENGTH - Integer.BYTES, 0);
// encrypt and write "zero length" as a placeholder, which will be read by concurrent requests, as long as encryption didn't finish:
encryptedContentLength(encryptedFile, 0l);
// encryptedContentLength(encryptedFile, 0l);
// write content:
// content encryption:
final Cipher cipher = this.aesCtrCipher(primaryMasterKey, iv.array(), Cipher.ENCRYPT_MODE);
final Mac contentMac = this.hmacSha256(hMacMasterKey);
final OutputStream out = new SeekableByteChannelOutputStream(encryptedFile);
final OutputStream macOut = new MacOutputStream(out, mac);
final OutputStream macOut = new MacOutputStream(out, contentMac);
final OutputStream cipheredOut = new CipherOutputStream(macOut, cipher);
final OutputStream blockSizeBufferedOut = new BufferedOutputStream(cipheredOut, AES_BLOCK_LENGTH);
final InputStream lengthLimitingIn = new CounterAwareInputStream(plaintextFile);
@ -546,14 +587,15 @@ public class Aes256Cryptor implements Cryptor, AesCryptographicConfiguration, Fi
plaintextSize = IOUtils.copyLarge(lengthLimitingIn, blockSizeBufferedOut);
} catch (CounterAwareInputLimitReachedException ex) {
encryptedFile.truncate(64l + CounterAwareInputStream.SIXTY_FOUR_GIGABYE);
encryptedContentLength(encryptedFile, CounterAwareInputStream.SIXTY_FOUR_GIGABYE);
// TODO
// encryptedContentLength(encryptedFile, CounterAwareInputStream.SIXTY_FOUR_GIGABYE);
// no additional padding needed here, as 64GiB is a multiple of 128bit
throw new CounterOverflowException("File size exceeds limit (64Gib). Aborting to prevent counter overflow.");
}
// ensure total byte count is a multiple of the block size, in CTR mode:
final int remainderToFillLastBlock = AES_BLOCK_LENGTH - (int) (plaintextSize % AES_BLOCK_LENGTH);
blockSizeBufferedOut.write(new byte[remainderToFillLastBlock]);
// final int remainderToFillLastBlock = AES_BLOCK_LENGTH - (int) (plaintextSize % AES_BLOCK_LENGTH);
// blockSizeBufferedOut.write(new byte[remainderToFillLastBlock]);
// for filesizes of up to 16GiB: append a few blocks of fake data:
if (plaintextSize < (long) (Integer.MAX_VALUE / 4) * AES_BLOCK_LENGTH) {
@ -566,15 +608,19 @@ public class Aes256Cryptor implements Cryptor, AesCryptographicConfiguration, Fi
}
blockSizeBufferedOut.flush();
// write MAC of total ciphertext:
macBuffer.clear();
macBuffer.put(mac.doFinal());
macBuffer.flip();
encryptedFile.position(16); // right behind the IV
encryptedFile.write(macBuffer); // 256 bit MAC
// encrypt and write plaintextSize:
encryptedContentLength(encryptedFile, plaintextSize);
// create and write header:
headerBuf.clear();
headerBuf.put(iv);
headerBuf.put(encryptContentLength(plaintextSize));
headerBuf.flip();
final Mac headerMac = this.hmacSha256(hMacMasterKey);
headerMac.update(headerBuf);
headerBuf.limit(96);
headerBuf.put(headerMac.doFinal());
headerBuf.put(contentMac.doFinal());
headerBuf.flip();
encryptedFile.position(0);
encryptedFile.write(headerBuf);
return plaintextSize;
}

8
main/crypto-aes/src/test/java/org/cryptomator/crypto/aes256/Aes256CryptorTest.java
View File

@ -82,7 +82,7 @@ public class Aes256CryptorTest {
final Aes256Cryptor cryptor = new Aes256Cryptor();
// encrypt:
final ByteBuffer encryptedData = ByteBuffer.allocate(96);
final ByteBuffer encryptedData = ByteBuffer.allocate(256);
final SeekableByteChannel encryptedOut = new ByteBufferBackedSeekableChannel(encryptedData);
cryptor.encryptFile(plaintextIn, encryptedOut);
IOUtils.closeQuietly(plaintextIn);
@ -114,7 +114,7 @@ public class Aes256CryptorTest {
final Aes256Cryptor cryptor = new Aes256Cryptor();
// encrypt:
final ByteBuffer encryptedData = ByteBuffer.allocate(96);
final ByteBuffer encryptedData = ByteBuffer.allocate(256);
final SeekableByteChannel encryptedOut = new ByteBufferBackedSeekableChannel(encryptedData);
cryptor.encryptFile(plaintextIn, encryptedOut);
IOUtils.closeQuietly(plaintextIn);
@ -146,7 +146,7 @@ public class Aes256CryptorTest {
final Aes256Cryptor cryptor = new Aes256Cryptor();
// encrypt:
final ByteBuffer encryptedData = ByteBuffer.allocate(96);
final ByteBuffer encryptedData = ByteBuffer.allocate(256);
final SeekableByteChannel encryptedOut = new ByteBufferBackedSeekableChannel(encryptedData);
cryptor.encryptFile(plaintextIn, encryptedOut);
IOUtils.closeQuietly(plaintextIn);
@ -185,7 +185,7 @@ public class Aes256CryptorTest {
final Aes256Cryptor cryptor = new Aes256Cryptor();
// encrypt:
final ByteBuffer encryptedData = ByteBuffer.allocate((int) (64 + plaintextData.length * 1.2));
final ByteBuffer encryptedData = ByteBuffer.allocate((int) (96 + plaintextData.length * 1.2));
final SeekableByteChannel encryptedOut = new ByteBufferBackedSeekableChannel(encryptedData);
cryptor.encryptFile(plaintextIn, encryptedOut);
IOUtils.closeQuietly(plaintextIn);

3
main/crypto-api/src/main/java/org/cryptomator/crypto/AbstractCryptorDecorator.java
View File

@ -11,6 +11,7 @@ import javax.security.auth.DestroyFailedException;
import org.cryptomator.crypto.exceptions.DecryptFailedException;
import org.cryptomator.crypto.exceptions.EncryptFailedException;
import org.cryptomator.crypto.exceptions.MacAuthenticationFailedException;
import org.cryptomator.crypto.exceptions.UnsupportedKeyLengthException;
import org.cryptomator.crypto.exceptions.WrongPasswordException;
@ -48,7 +49,7 @@ public class AbstractCryptorDecorator implements Cryptor {
}
@Override
public Long decryptedContentLength(SeekableByteChannel encryptedFile) throws IOException {
public Long decryptedContentLength(SeekableByteChannel encryptedFile) throws IOException, MacAuthenticationFailedException {
return cryptor.decryptedContentLength(encryptedFile);
}

25
main/crypto-api/src/main/java/org/cryptomator/crypto/Cryptor.java
View File

@ -19,6 +19,7 @@ import javax.security.auth.Destroyable;
import org.cryptomator.crypto.exceptions.DecryptFailedException;
import org.cryptomator.crypto.exceptions.EncryptFailedException;
import org.cryptomator.crypto.exceptions.MacAuthenticationFailedException;
import org.cryptomator.crypto.exceptions.UnsupportedKeyLengthException;
import org.cryptomator.crypto.exceptions.WrongPasswordException;
@ -36,20 +37,16 @@ public interface Cryptor extends Destroyable {
* Reads the encrypted masterkey from the given input stream and decrypts it with the given password.
*
* @throws DecryptFailedException If the decryption failed for various reasons (including wrong password).
* @throws WrongPasswordException If the provided password was wrong. Note: Sometimes the algorithm itself fails due to a wrong
* password. In this case a DecryptFailedException will be thrown.
* @throws UnsupportedKeyLengthException If the masterkey has been encrypted with a higher key length than supported by the system. In
* this case Java JCE needs to be installed.
* @throws WrongPasswordException If the provided password was wrong. Note: Sometimes the algorithm itself fails due to a wrong password. In this case a DecryptFailedException will be thrown.
* @throws UnsupportedKeyLengthException If the masterkey has been encrypted with a higher key length than supported by the system. In this case Java JCE needs to be installed.
*/
void decryptMasterKey(InputStream in, CharSequence password) throws DecryptFailedException, WrongPasswordException, UnsupportedKeyLengthException, IOException;
/**
* Encrypts a given plaintext path representing a directory structure. See {@link #encryptFilename(String, CryptorMetadataSupport)} for
* contents inside directories.
* Encrypts a given plaintext path representing a directory structure. See {@link #encryptFilename(String, CryptorMetadataSupport)} for contents inside directories.
*
* @param cleartextPath A relative path (UTF-8 encoded), whose path components are separated by '/'
* @param nativePathSep Path separator like "/" used on local file system. Must not be null, even if cleartextPath is a sole file name
* without any path separators.
* @param nativePathSep Path separator like "/" used on local file system. Must not be null, even if cleartextPath is a sole file name without any path separators.
* @return Encrypted path.
*/
String encryptDirectoryPath(String cleartextPath, String nativePathSep);
@ -58,8 +55,7 @@ public interface Cryptor extends Destroyable {
* Encrypts the name of a file. See {@link #encryptDirectoryPath(String, char)} for parent dir.
*
* @param cleartextName A plaintext filename without any preceeding directory paths.
* @param ioSupport Support object allowing the Cryptor to read and write its own metadata to a storage space associated with this
* support object.
* @param ioSupport Support object allowing the Cryptor to read and write its own metadata to a storage space associated with this support object.
* @return Encrypted filename.
* @throws IOException If ioSupport throws an IOException
*/
@ -69,8 +65,7 @@ public interface Cryptor extends Destroyable {
* Decrypts the name of a file.
*
* @param ciphertextName A ciphertext filename without any preceeding directory paths.
* @param ioSupport Support object allowing the Cryptor to read and write its own metadata to a storage space associated with this
* support object.
* @param ioSupport Support object allowing the Cryptor to read and write its own metadata to a storage space associated with this support object.
* @return Decrypted filename.
* @throws DecryptFailedException If the decryption failed for various reasons (including wrong password).
* @throws IOException If ioSupport throws an IOException
@ -80,8 +75,9 @@ public interface Cryptor extends Destroyable {
/**
* @param metadataSupport Support object allowing the Cryptor to read and write its own metadata to the location of the encrypted file.
* @return Content length of the decrypted file or <code>null</code> if unknown.
* @throws MacAuthenticationFailedException If the MAC auth failed.
*/
Long decryptedContentLength(SeekableByteChannel encryptedFile) throws IOException;
Long decryptedContentLength(SeekableByteChannel encryptedFile) throws IOException, MacAuthenticationFailedException;
/**
* @return true, if the stored MAC matches the calculated one.
@ -108,8 +104,7 @@ public interface Cryptor extends Destroyable {
Long encryptFile(InputStream plaintextFile, SeekableByteChannel encryptedFile) throws IOException, EncryptFailedException;
/**
* @return A filter, that returns <code>true</code> for encrypted files, i.e. if the file is an actual user payload and not a supporting
* metadata file of the {@link Cryptor}.
* @return A filter, that returns <code>true</code> for encrypted files, i.e. if the file is an actual user payload and not a supporting metadata file of the {@link Cryptor}.
*/
Filter<Path> getPayloadFilesFilter();