GordianKnot Symmetric Stream Ciphers
Overview
Stream Ciphers are supported via the GordianCipherFactory interface.
GordianKnot supports most Symmetric Stream Ciphers available from BouncyCastle plus some additional ciphers.
A key for stream encryption is created by specifying the algorithm and keySize as a GordianStreamKeySpec.
A cipher for stream encryption is created by specifying the GordianStreamKeySpec (plus variant details eg AEAD) as a GordianStreamCipherSpec and can be used similarly to a blockCipher.
A keyGenerator for a GordianStreamKeySpec can be created, which can be used to generate random keys for the keySpec
JCA provides a subset of available algorithms as indicated
Key Generation
Algorithms are represented by GordianSymKeySpec. A GordianKeyGenerator is obtained via the keySpec, and then keys are generated by the generator.
Sample
/* Access factory */
final GordianFactory myBaseFactory = GordianGenerator.createFactory();
final GordianCipherFactory myCipherFactory = myBaseFactory.getCipherFactory();
/* Access keyGenerator */
final GordianStreamKeySpec mySpec = GordianStreamKeySpecBuilder.hc(GordianLength.LEN_256);
final GordianKeyGenerator<GordianStreamKeySpec> myGenerator = myCipherFactory.getKeyGenerator(mySpec);
final GordianKey<GordianStreamKeySpec> myKey = myGenerator.generateKey();
Algorithms
The following streamKey algorithms are supported.
| Algorithm | Variant | JCA | KeySize | ||||
|---|---|---|---|---|---|---|---|
| 128 | 192 | 256 | 512 | 1024 | |||
| ChaCha20 | Standard | Y | Y | Y | |||
| ChaCha7359 | Y | Y | |||||
| XChaCha20 | Y | ||||||
| Salsa20 | Standard | Y | Y | Y | |||
| XSalsa20 | Y | Y | |||||
| HC | HC128 | Y | Y | ||||
| HC256 | Y | Y | |||||
| VMPC | Standard KSA3 | Y | Y | Y | Y | Y | Y |
| ISAAC | Y | Y | Y | Y | Y | ||
| RC4 | Y | Y | Y | Y | Y | Y | |
| Grain128 | Y | Y | |||||
| Rabbit | Y | ||||||
| Sosemanuk | Y | ||||||
| Snow3G | Y | ||||||
| Zuc | Zuc-128 | Y | Y | ||||
| Zuc-256 | Y | Y | |||||
| SkeinXof | Skein-256 | Y | Y | Y | Y | Y | |
| Skein-512 | Y | Y | Y | Y | Y | ||
| Skein-1024 | Y | Y | Y | Y | Y | ||
| Blake2X | Blake2Xs | Y | Y | Y | |||
| Blake2Xb | Y | Y | Y | Y | |||
| Blake3Xof | Y | ||||||
| Ascon | Y | ||||||
| Elephant | 160, 176, 200 | Y | |||||
| ISAP | A128, A128A, K128, K128A | Y | |||||
| PhotonBeetle | Y | ||||||
| Sparkle | 128_128, 256_128 | Y | |||||
| 192_192 | Y | ||||||
| 256_256 | Y | ||||||
| Xoodyak | Y | ||||||
Cipher Usage
Cipher Algorithms are represented by GordianStreamCipherSpec. A GordianStreamCipher is obtained via the cipherSpec, and then messages are encrypted/decrypted by the cipher.
Sample
/* Access factory */
final GordianFactory myBaseFactory = GordianGenerator.createFactory();
final GordianCipherFactory myCipherFactory = myBaseFactory.getCipherFactory();
/* Create key */
final GordianStreamKeySpec myKeySpec = GordianStreamKeySpecBuilder.hc(GordianLength.LEN_256);
final GordianKeyGenerator<GordianStreamKeySpec> myGenerator = myCipherFactory.getKeyGenerator(myKeySpec);
final GordianKey<GordianStreamKeySpec> myKey = myGenerator.generateKey();
/* Create cipher */
final GordianStreamCipherSpec myCipherSpec = GordianStreamCipherSpecBuilder.stream(myKeySpec);
final GordianStreamCipher myCipher = myCipherFactory.createStreamKeyCipher(myCipherSpec);
/* Encrypt message with random nonce */
GordianCipherParameters myParams = GordianCipherParameters.keyWithRandomNonce(myKey);
myCipher.initForEncrypt(myParams);
final byte[] myMessage = ...
int myOutLen = myCipher.getOutputLength(myMessage.length);
final byte[] myEncrypted = new byte[myOutLen];
int myProcessed = myCipher.update(myMessage, 0, myMessage.length, myEncrypted);
myCipher.finish(myEncrypted, myProcessed);
/* Decrypt message */
myParams = GordianCipherParameters.keyWithNonce(myKey, myCipher.getNonce());
myCipher.initForDecrypt(myParams);
myOutLen = myCipher.getOutputLength(myEncrypted.length);
final byte[] myResult = new byte[myOutLen];
myProcessed = myCipher.update(myEncrypted, 0, myEncrypted.length, myResult);
myCipher.finish(myResult, myProcessed);