| package org.bouncycastle.crypto.engines; |
| |
| import org.bouncycastle.crypto.BlockCipher; |
| import org.bouncycastle.crypto.CipherParameters; |
| import org.bouncycastle.crypto.DataLengthException; |
| import org.bouncycastle.crypto.OutputLengthException; |
| import org.bouncycastle.crypto.params.KeyParameter; |
| |
| /** |
| * a class that provides a basic SKIPJACK engine. |
| */ |
| public class SkipjackEngine |
| implements BlockCipher |
| { |
| static final int BLOCK_SIZE = 8; |
| |
| static short ftable[] = |
| { |
| 0xa3, 0xd7, 0x09, 0x83, 0xf8, 0x48, 0xf6, 0xf4, 0xb3, 0x21, 0x15, 0x78, 0x99, 0xb1, 0xaf, 0xf9, |
| 0xe7, 0x2d, 0x4d, 0x8a, 0xce, 0x4c, 0xca, 0x2e, 0x52, 0x95, 0xd9, 0x1e, 0x4e, 0x38, 0x44, 0x28, |
| 0x0a, 0xdf, 0x02, 0xa0, 0x17, 0xf1, 0x60, 0x68, 0x12, 0xb7, 0x7a, 0xc3, 0xe9, 0xfa, 0x3d, 0x53, |
| 0x96, 0x84, 0x6b, 0xba, 0xf2, 0x63, 0x9a, 0x19, 0x7c, 0xae, 0xe5, 0xf5, 0xf7, 0x16, 0x6a, 0xa2, |
| 0x39, 0xb6, 0x7b, 0x0f, 0xc1, 0x93, 0x81, 0x1b, 0xee, 0xb4, 0x1a, 0xea, 0xd0, 0x91, 0x2f, 0xb8, |
| 0x55, 0xb9, 0xda, 0x85, 0x3f, 0x41, 0xbf, 0xe0, 0x5a, 0x58, 0x80, 0x5f, 0x66, 0x0b, 0xd8, 0x90, |
| 0x35, 0xd5, 0xc0, 0xa7, 0x33, 0x06, 0x65, 0x69, 0x45, 0x00, 0x94, 0x56, 0x6d, 0x98, 0x9b, 0x76, |
| 0x97, 0xfc, 0xb2, 0xc2, 0xb0, 0xfe, 0xdb, 0x20, 0xe1, 0xeb, 0xd6, 0xe4, 0xdd, 0x47, 0x4a, 0x1d, |
| 0x42, 0xed, 0x9e, 0x6e, 0x49, 0x3c, 0xcd, 0x43, 0x27, 0xd2, 0x07, 0xd4, 0xde, 0xc7, 0x67, 0x18, |
| 0x89, 0xcb, 0x30, 0x1f, 0x8d, 0xc6, 0x8f, 0xaa, 0xc8, 0x74, 0xdc, 0xc9, 0x5d, 0x5c, 0x31, 0xa4, |
| 0x70, 0x88, 0x61, 0x2c, 0x9f, 0x0d, 0x2b, 0x87, 0x50, 0x82, 0x54, 0x64, 0x26, 0x7d, 0x03, 0x40, |
| 0x34, 0x4b, 0x1c, 0x73, 0xd1, 0xc4, 0xfd, 0x3b, 0xcc, 0xfb, 0x7f, 0xab, 0xe6, 0x3e, 0x5b, 0xa5, |
| 0xad, 0x04, 0x23, 0x9c, 0x14, 0x51, 0x22, 0xf0, 0x29, 0x79, 0x71, 0x7e, 0xff, 0x8c, 0x0e, 0xe2, |
| 0x0c, 0xef, 0xbc, 0x72, 0x75, 0x6f, 0x37, 0xa1, 0xec, 0xd3, 0x8e, 0x62, 0x8b, 0x86, 0x10, 0xe8, |
| 0x08, 0x77, 0x11, 0xbe, 0x92, 0x4f, 0x24, 0xc5, 0x32, 0x36, 0x9d, 0xcf, 0xf3, 0xa6, 0xbb, 0xac, |
| 0x5e, 0x6c, 0xa9, 0x13, 0x57, 0x25, 0xb5, 0xe3, 0xbd, 0xa8, 0x3a, 0x01, 0x05, 0x59, 0x2a, 0x46 |
| }; |
| |
| private int[] key0, key1, key2, key3; |
| private boolean encrypting; |
| |
| /** |
| * initialise a SKIPJACK cipher. |
| * |
| * @param encrypting 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 encrypting, |
| CipherParameters params) |
| { |
| if (!(params instanceof KeyParameter)) |
| { |
| throw new IllegalArgumentException("invalid parameter passed to SKIPJACK init - " + params.getClass().getName()); |
| } |
| |
| byte[] keyBytes = ((KeyParameter)params).getKey(); |
| |
| this.encrypting = encrypting; |
| this.key0 = new int[32]; |
| this.key1 = new int[32]; |
| this.key2 = new int[32]; |
| this.key3 = new int[32]; |
| |
| // |
| // expand the key to 128 bytes in 4 parts (saving us a modulo, multiply |
| // and an addition). |
| // |
| for (int i = 0; i < 32; i ++) |
| { |
| key0[i] = keyBytes[(i * 4) % 10] & 0xff; |
| key1[i] = keyBytes[(i * 4 + 1) % 10] & 0xff; |
| key2[i] = keyBytes[(i * 4 + 2) % 10] & 0xff; |
| key3[i] = keyBytes[(i * 4 + 3) % 10] & 0xff; |
| } |
| } |
| |
| public String getAlgorithmName() |
| { |
| return "SKIPJACK"; |
| } |
| |
| public int getBlockSize() |
| { |
| return BLOCK_SIZE; |
| } |
| |
| public int processBlock( |
| byte[] in, |
| int inOff, |
| byte[] out, |
| int outOff) |
| { |
| if (key1 == null) |
| { |
| throw new IllegalStateException("SKIPJACK engine not initialised"); |
| } |
| |
| if ((inOff + BLOCK_SIZE) > in.length) |
| { |
| throw new DataLengthException("input buffer too short"); |
| } |
| |
| if ((outOff + BLOCK_SIZE) > out.length) |
| { |
| throw new OutputLengthException("output buffer too short"); |
| } |
| |
| if (encrypting) |
| { |
| encryptBlock(in, inOff, out, outOff); |
| } |
| else |
| { |
| decryptBlock(in, inOff, out, outOff); |
| } |
| |
| return BLOCK_SIZE; |
| } |
| |
| public void reset() |
| { |
| } |
| |
| /** |
| * The G permutation |
| */ |
| private int g( |
| int k, |
| int w) |
| { |
| int g1, g2, g3, g4, g5, g6; |
| |
| g1 = (w >> 8) & 0xff; |
| g2 = w & 0xff; |
| |
| g3 = ftable[g2 ^ key0[k]] ^ g1; |
| g4 = ftable[g3 ^ key1[k]] ^ g2; |
| g5 = ftable[g4 ^ key2[k]] ^ g3; |
| g6 = ftable[g5 ^ key3[k]] ^ g4; |
| |
| return ((g5 << 8) + g6); |
| } |
| |
| public int encryptBlock( |
| byte[] in, |
| int inOff, |
| byte[] out, |
| int outOff) |
| { |
| int w1 = (in[inOff + 0] << 8) + (in[inOff + 1] & 0xff); |
| int w2 = (in[inOff + 2] << 8) + (in[inOff + 3] & 0xff); |
| int w3 = (in[inOff + 4] << 8) + (in[inOff + 5] & 0xff); |
| int w4 = (in[inOff + 6] << 8) + (in[inOff + 7] & 0xff); |
| |
| int k = 0; |
| |
| for (int t = 0; t < 2; t++) |
| { |
| for(int i = 0; i < 8; i++) |
| { |
| int tmp = w4; |
| w4 = w3; |
| w3 = w2; |
| w2 = g(k, w1); |
| w1 = w2 ^ tmp ^ (k + 1); |
| k++; |
| } |
| |
| for(int i = 0; i < 8; i++) |
| { |
| int tmp = w4; |
| w4 = w3; |
| w3 = w1 ^ w2 ^ (k + 1); |
| w2 = g(k, w1); |
| w1 = tmp; |
| k++; |
| } |
| } |
| |
| out[outOff + 0] = (byte)((w1 >> 8)); |
| out[outOff + 1] = (byte)(w1); |
| out[outOff + 2] = (byte)((w2 >> 8)); |
| out[outOff + 3] = (byte)(w2); |
| out[outOff + 4] = (byte)((w3 >> 8)); |
| out[outOff + 5] = (byte)(w3); |
| out[outOff + 6] = (byte)((w4 >> 8)); |
| out[outOff + 7] = (byte)(w4); |
| |
| return BLOCK_SIZE; |
| } |
| |
| /** |
| * the inverse of the G permutation. |
| */ |
| private int h( |
| int k, |
| int w) |
| { |
| int h1, h2, h3, h4, h5, h6; |
| |
| h1 = w & 0xff; |
| h2 = (w >> 8) & 0xff; |
| |
| h3 = ftable[h2 ^ key3[k]] ^ h1; |
| h4 = ftable[h3 ^ key2[k]] ^ h2; |
| h5 = ftable[h4 ^ key1[k]] ^ h3; |
| h6 = ftable[h5 ^ key0[k]] ^ h4; |
| |
| return ((h6 << 8) + h5); |
| } |
| |
| public int decryptBlock( |
| byte[] in, |
| int inOff, |
| byte[] out, |
| int outOff) |
| { |
| int w2 = (in[inOff + 0] << 8) + (in[inOff + 1] & 0xff); |
| int w1 = (in[inOff + 2] << 8) + (in[inOff + 3] & 0xff); |
| int w4 = (in[inOff + 4] << 8) + (in[inOff + 5] & 0xff); |
| int w3 = (in[inOff + 6] << 8) + (in[inOff + 7] & 0xff); |
| |
| int k = 31; |
| |
| for (int t = 0; t < 2; t++) |
| { |
| for(int i = 0; i < 8; i++) |
| { |
| int tmp = w4; |
| w4 = w3; |
| w3 = w2; |
| w2 = h(k, w1); |
| w1 = w2 ^ tmp ^ (k + 1); |
| k--; |
| } |
| |
| for(int i = 0; i < 8; i++) |
| { |
| int tmp = w4; |
| w4 = w3; |
| w3 = w1 ^ w2 ^ (k + 1); |
| w2 = h(k, w1); |
| w1 = tmp; |
| k--; |
| } |
| } |
| |
| out[outOff + 0] = (byte)((w2 >> 8)); |
| out[outOff + 1] = (byte)(w2); |
| out[outOff + 2] = (byte)((w1 >> 8)); |
| out[outOff + 3] = (byte)(w1); |
| out[outOff + 4] = (byte)((w4 >> 8)); |
| out[outOff + 5] = (byte)(w4); |
| out[outOff + 6] = (byte)((w3 >> 8)); |
| out[outOff + 7] = (byte)(w3); |
| |
| return BLOCK_SIZE; |
| } |
| } |