diff options
Diffstat (limited to 'Crypto/src/crypto/engines/NoekeonEngine.cs')
| -rw-r--r-- | Crypto/src/crypto/engines/NoekeonEngine.cs | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/Crypto/src/crypto/engines/NoekeonEngine.cs b/Crypto/src/crypto/engines/NoekeonEngine.cs new file mode 100644 index 000000000..b73e696a9 --- /dev/null +++ b/Crypto/src/crypto/engines/NoekeonEngine.cs @@ -0,0 +1,240 @@ +using System; + +using Org.BouncyCastle.Crypto.Parameters; +using Org.BouncyCastle.Crypto.Utilities; + +namespace Org.BouncyCastle.Crypto.Engines +{ + /** + * A Noekeon engine, using direct-key mode. + */ + public class NoekeonEngine + : IBlockCipher + { + private const int GenericSize = 16; // Block and key size, as well as the amount of rounds. + + private static readonly uint[] nullVector = + { + 0x00, 0x00, 0x00, 0x00 // Used in decryption + }; + + private static readonly uint[] roundConstants = + { + 0x80, 0x1b, 0x36, 0x6c, + 0xd8, 0xab, 0x4d, 0x9a, + 0x2f, 0x5e, 0xbc, 0x63, + 0xc6, 0x97, 0x35, 0x6a, + 0xd4 + }; + + private uint[] state = new uint[4], // a + subKeys = new uint[4], // k + decryptKeys = new uint[4]; + + private bool _initialised, _forEncryption; + + /** + * Create an instance of the Noekeon encryption algorithm + * and set some defaults + */ + public NoekeonEngine() + { + _initialised = false; + } + + public string AlgorithmName + { + get { return "Noekeon"; } + } + + public bool IsPartialBlockOkay + { + get { return false; } + } + + public int GetBlockSize() + { + return GenericSize; + } + + /** + * initialise + * + * @param forEncryption whether or not we are for encryption. + * @param params the parameters required to set up the cipher. + * @exception ArgumentException if the params argument is + * inappropriate. + */ + public void Init( + bool forEncryption, + ICipherParameters parameters) + { + if (!(parameters is KeyParameter)) + throw new ArgumentException("Invalid parameters passed to Noekeon init - " + parameters.GetType().Name, "parameters"); + + _forEncryption = forEncryption; + _initialised = true; + + KeyParameter p = (KeyParameter) parameters; + + setKey(p.GetKey()); + } + + public int ProcessBlock( + byte[] input, + int inOff, + byte[] output, + int outOff) + { + if (!_initialised) + throw new InvalidOperationException(AlgorithmName + " not initialised"); + if ((inOff + GenericSize) > input.Length) + throw new DataLengthException("input buffer too short"); + if ((outOff + GenericSize) > output.Length) + throw new DataLengthException("output buffer too short"); + + return _forEncryption + ? encryptBlock(input, inOff, output, outOff) + : decryptBlock(input, inOff, output, outOff); + } + + public void Reset() + { + // TODO This should do something in case the encryption is aborted + } + + /** + * Re-key the cipher. + * + * @param key the key to be used + */ + private void setKey(byte[] key) + { + subKeys[0] = Pack.BE_To_UInt32(key, 0); + subKeys[1] = Pack.BE_To_UInt32(key, 4); + subKeys[2] = Pack.BE_To_UInt32(key, 8); + subKeys[3] = Pack.BE_To_UInt32(key, 12); + } + + private int encryptBlock( + byte[] input, + int inOff, + byte[] output, + int outOff) + { + state[0] = Pack.BE_To_UInt32(input, inOff); + state[1] = Pack.BE_To_UInt32(input, inOff+4); + state[2] = Pack.BE_To_UInt32(input, inOff+8); + state[3] = Pack.BE_To_UInt32(input, inOff+12); + + int i; + for (i = 0; i < GenericSize; i++) + { + state[0] ^= roundConstants[i]; + theta(state, subKeys); + pi1(state); + gamma(state); + pi2(state); + } + + state[0] ^= roundConstants[i]; + theta(state, subKeys); + + Pack.UInt32_To_BE(state[0], output, outOff); + Pack.UInt32_To_BE(state[1], output, outOff+4); + Pack.UInt32_To_BE(state[2], output, outOff+8); + Pack.UInt32_To_BE(state[3], output, outOff+12); + + return GenericSize; + } + + private int decryptBlock( + byte[] input, + int inOff, + byte[] output, + int outOff) + { + state[0] = Pack.BE_To_UInt32(input, inOff); + state[1] = Pack.BE_To_UInt32(input, inOff+4); + state[2] = Pack.BE_To_UInt32(input, inOff+8); + state[3] = Pack.BE_To_UInt32(input, inOff+12); + + Array.Copy(subKeys, 0, decryptKeys, 0, subKeys.Length); + theta(decryptKeys, nullVector); + + int i; + for (i = GenericSize; i > 0; i--) + { + theta(state, decryptKeys); + state[0] ^= roundConstants[i]; + pi1(state); + gamma(state); + pi2(state); + } + + theta(state, decryptKeys); + state[0] ^= roundConstants[i]; + + Pack.UInt32_To_BE(state[0], output, outOff); + Pack.UInt32_To_BE(state[1], output, outOff+4); + Pack.UInt32_To_BE(state[2], output, outOff+8); + Pack.UInt32_To_BE(state[3], output, outOff+12); + + return GenericSize; + } + + private void gamma(uint[] a) + { + a[1] ^= ~a[3] & ~a[2]; + a[0] ^= a[2] & a[1]; + + uint tmp = a[3]; + a[3] = a[0]; + a[0] = tmp; + a[2] ^= a[0]^a[1]^a[3]; + + a[1] ^= ~a[3] & ~a[2]; + a[0] ^= a[2] & a[1]; + } + + private void theta(uint[] a, uint[] k) + { + uint tmp; + tmp = a[0]^a[2]; + tmp ^= rotl(tmp,8)^rotl(tmp,24); + a[1] ^= tmp; + a[3] ^= tmp; + + for (int i = 0; i < 4; i++) + { + a[i] ^= k[i]; + } + + tmp = a[1]^a[3]; + tmp ^= rotl(tmp,8)^rotl(tmp,24); + a[0] ^= tmp; + a[2] ^= tmp; + } + + private void pi1(uint[] a) + { + a[1] = rotl(a[1], 1); + a[2] = rotl(a[2], 5); + a[3] = rotl(a[3], 2); + } + + private void pi2(uint[] a) + { + a[1] = rotl(a[1], 31); + a[2] = rotl(a[2], 27); + a[3] = rotl(a[3], 30); + } + + // Helpers + + private uint rotl(uint x, int y) + { + return (x << y) | (x >> (32-y)); + } + } +} |