package org.bouncycastle.crypto.engines;

import org.bouncycastle.crypto.BlockCipher;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.DataLengthException;
import org.bouncycastle.crypto.params.KeyParameter;

A Noekeon engine, using direct-key mode.
/** * A Noekeon engine, using direct-key mode. */
public class NoekeonEngine implements BlockCipher { private static final int genericSize = 16; // Block and key size, as well as the amount of rounds. private static final int[] nullVector = { 0x00, 0x00, 0x00, 0x00 // Used in decryption }, roundConstants = { 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4 }; private int[] state = new int[4], // a subKeys = new int[4], // k decryptKeys = new int[4]; private boolean _initialised, _forEncryption;
Create an instance of the Noekeon encryption algorithm and set some defaults
/** * Create an instance of the Noekeon encryption algorithm * and set some defaults */
public NoekeonEngine() { _initialised = false; } public String getAlgorithmName() { return "Noekeon"; } public int getBlockSize() { return genericSize; }
initialise
Params:
  • forEncryption – whether or not we are for encryption.
  • params – the parameters required to set up the cipher.
Throws:
/** * initialise * * @param forEncryption whether or not we are for encryption. * @param params the parameters required to set up the cipher. * @exception IllegalArgumentException if the params argument is * inappropriate. */
public void init( boolean forEncryption, CipherParameters params) { if (!(params instanceof KeyParameter)) { throw new IllegalArgumentException("invalid parameter passed to Noekeon init - " + params.getClass().getName()); } _forEncryption = forEncryption; _initialised = true; KeyParameter p = (KeyParameter)params; setKey(p.getKey()); } public int processBlock( byte[] in, int inOff, byte[] out, int outOff) { if (!_initialised) { throw new IllegalStateException(getAlgorithmName()+" not initialised"); } if ((inOff + genericSize) > in.length) { throw new DataLengthException("input buffer too short"); } if ((outOff + genericSize) > out.length) { throw new DataLengthException("output buffer too short"); } return (_forEncryption) ? encryptBlock(in, inOff, out, outOff) : decryptBlock(in, inOff, out, outOff); } public void reset() { }
Re-key the cipher.

Params:
  • key – the key to be used
/** * Re-key the cipher. * <p> * @param key the key to be used */
private void setKey( byte[] key) { subKeys[0] = bytesToIntBig(key, 0); subKeys[1] = bytesToIntBig(key, 4); subKeys[2] = bytesToIntBig(key, 8); subKeys[3] = bytesToIntBig(key, 12); } private int encryptBlock( byte[] in, int inOff, byte[] out, int outOff) { state[0] = bytesToIntBig(in, inOff); state[1] = bytesToIntBig(in, inOff+4); state[2] = bytesToIntBig(in, inOff+8); state[3] = bytesToIntBig(in, 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); intToBytesBig(state[0], out, outOff); intToBytesBig(state[1], out, outOff+4); intToBytesBig(state[2], out, outOff+8); intToBytesBig(state[3], out, outOff+12); return genericSize; } private int decryptBlock( byte[] in, int inOff, byte[] out, int outOff) { state[0] = bytesToIntBig(in, inOff); state[1] = bytesToIntBig(in, inOff+4); state[2] = bytesToIntBig(in, inOff+8); state[3] = bytesToIntBig(in, inOff+12); System.arraycopy(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]; intToBytesBig(state[0], out, outOff); intToBytesBig(state[1], out, outOff+4); intToBytesBig(state[2], out, outOff+8); intToBytesBig(state[3], out, outOff+12); return genericSize; } private void gamma(int[] a) { a[1] ^= ~a[3] & ~a[2]; a[0] ^= a[2] & a[1]; int 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(int[] a, int[] k) { int 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(int[] a) { a[1] = rotl(a[1], 1); a[2] = rotl(a[2], 5); a[3] = rotl(a[3], 2); } private void pi2(int[] a) { a[1] = rotl(a[1], 31); a[2] = rotl(a[2], 27); a[3] = rotl(a[3], 30); } // Helpers private int bytesToIntBig(byte[] in, int off) { return ((in[off++]) << 24) | ((in[off++] & 0xff) << 16) | ((in[off++] & 0xff) << 8) | (in[off ] & 0xff); } private void intToBytesBig(int x, byte[] out, int off) { out[off++] = (byte)(x >>> 24); out[off++] = (byte)(x >>> 16); out[off++] = (byte)(x >>> 8); out[off ] = (byte)x; } private int rotl(int x, int y) { return (x << y) | (x >>> (32-y)); } }