| 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; |
| import org.bouncycastle.crypto.params.RC2Parameters; |
| |
| /** |
| * an implementation of RC2 as described in RFC 2268 |
| * "A Description of the RC2(r) Encryption Algorithm" R. Rivest. |
| */ |
| public class RC2Engine |
| implements BlockCipher |
| { |
| // |
| // the values we use for key expansion (based on the digits of PI) |
| // |
| private static byte[] piTable = |
| { |
| (byte)0xd9, (byte)0x78, (byte)0xf9, (byte)0xc4, (byte)0x19, (byte)0xdd, (byte)0xb5, (byte)0xed, |
| (byte)0x28, (byte)0xe9, (byte)0xfd, (byte)0x79, (byte)0x4a, (byte)0xa0, (byte)0xd8, (byte)0x9d, |
| (byte)0xc6, (byte)0x7e, (byte)0x37, (byte)0x83, (byte)0x2b, (byte)0x76, (byte)0x53, (byte)0x8e, |
| (byte)0x62, (byte)0x4c, (byte)0x64, (byte)0x88, (byte)0x44, (byte)0x8b, (byte)0xfb, (byte)0xa2, |
| (byte)0x17, (byte)0x9a, (byte)0x59, (byte)0xf5, (byte)0x87, (byte)0xb3, (byte)0x4f, (byte)0x13, |
| (byte)0x61, (byte)0x45, (byte)0x6d, (byte)0x8d, (byte)0x9, (byte)0x81, (byte)0x7d, (byte)0x32, |
| (byte)0xbd, (byte)0x8f, (byte)0x40, (byte)0xeb, (byte)0x86, (byte)0xb7, (byte)0x7b, (byte)0xb, |
| (byte)0xf0, (byte)0x95, (byte)0x21, (byte)0x22, (byte)0x5c, (byte)0x6b, (byte)0x4e, (byte)0x82, |
| (byte)0x54, (byte)0xd6, (byte)0x65, (byte)0x93, (byte)0xce, (byte)0x60, (byte)0xb2, (byte)0x1c, |
| (byte)0x73, (byte)0x56, (byte)0xc0, (byte)0x14, (byte)0xa7, (byte)0x8c, (byte)0xf1, (byte)0xdc, |
| (byte)0x12, (byte)0x75, (byte)0xca, (byte)0x1f, (byte)0x3b, (byte)0xbe, (byte)0xe4, (byte)0xd1, |
| (byte)0x42, (byte)0x3d, (byte)0xd4, (byte)0x30, (byte)0xa3, (byte)0x3c, (byte)0xb6, (byte)0x26, |
| (byte)0x6f, (byte)0xbf, (byte)0xe, (byte)0xda, (byte)0x46, (byte)0x69, (byte)0x7, (byte)0x57, |
| (byte)0x27, (byte)0xf2, (byte)0x1d, (byte)0x9b, (byte)0xbc, (byte)0x94, (byte)0x43, (byte)0x3, |
| (byte)0xf8, (byte)0x11, (byte)0xc7, (byte)0xf6, (byte)0x90, (byte)0xef, (byte)0x3e, (byte)0xe7, |
| (byte)0x6, (byte)0xc3, (byte)0xd5, (byte)0x2f, (byte)0xc8, (byte)0x66, (byte)0x1e, (byte)0xd7, |
| (byte)0x8, (byte)0xe8, (byte)0xea, (byte)0xde, (byte)0x80, (byte)0x52, (byte)0xee, (byte)0xf7, |
| (byte)0x84, (byte)0xaa, (byte)0x72, (byte)0xac, (byte)0x35, (byte)0x4d, (byte)0x6a, (byte)0x2a, |
| (byte)0x96, (byte)0x1a, (byte)0xd2, (byte)0x71, (byte)0x5a, (byte)0x15, (byte)0x49, (byte)0x74, |
| (byte)0x4b, (byte)0x9f, (byte)0xd0, (byte)0x5e, (byte)0x4, (byte)0x18, (byte)0xa4, (byte)0xec, |
| (byte)0xc2, (byte)0xe0, (byte)0x41, (byte)0x6e, (byte)0xf, (byte)0x51, (byte)0xcb, (byte)0xcc, |
| (byte)0x24, (byte)0x91, (byte)0xaf, (byte)0x50, (byte)0xa1, (byte)0xf4, (byte)0x70, (byte)0x39, |
| (byte)0x99, (byte)0x7c, (byte)0x3a, (byte)0x85, (byte)0x23, (byte)0xb8, (byte)0xb4, (byte)0x7a, |
| (byte)0xfc, (byte)0x2, (byte)0x36, (byte)0x5b, (byte)0x25, (byte)0x55, (byte)0x97, (byte)0x31, |
| (byte)0x2d, (byte)0x5d, (byte)0xfa, (byte)0x98, (byte)0xe3, (byte)0x8a, (byte)0x92, (byte)0xae, |
| (byte)0x5, (byte)0xdf, (byte)0x29, (byte)0x10, (byte)0x67, (byte)0x6c, (byte)0xba, (byte)0xc9, |
| (byte)0xd3, (byte)0x0, (byte)0xe6, (byte)0xcf, (byte)0xe1, (byte)0x9e, (byte)0xa8, (byte)0x2c, |
| (byte)0x63, (byte)0x16, (byte)0x1, (byte)0x3f, (byte)0x58, (byte)0xe2, (byte)0x89, (byte)0xa9, |
| (byte)0xd, (byte)0x38, (byte)0x34, (byte)0x1b, (byte)0xab, (byte)0x33, (byte)0xff, (byte)0xb0, |
| (byte)0xbb, (byte)0x48, (byte)0xc, (byte)0x5f, (byte)0xb9, (byte)0xb1, (byte)0xcd, (byte)0x2e, |
| (byte)0xc5, (byte)0xf3, (byte)0xdb, (byte)0x47, (byte)0xe5, (byte)0xa5, (byte)0x9c, (byte)0x77, |
| (byte)0xa, (byte)0xa6, (byte)0x20, (byte)0x68, (byte)0xfe, (byte)0x7f, (byte)0xc1, (byte)0xad |
| }; |
| |
| private static final int BLOCK_SIZE = 8; |
| |
| private int[] workingKey; |
| private boolean encrypting; |
| |
| private int[] generateWorkingKey( |
| byte[] key, |
| int bits) |
| { |
| int x; |
| int[] xKey = new int[128]; |
| |
| for (int i = 0; i != key.length; i++) |
| { |
| xKey[i] = key[i] & 0xff; |
| } |
| |
| // Phase 1: Expand input key to 128 bytes |
| int len = key.length; |
| |
| if (len < 128) |
| { |
| int index = 0; |
| |
| x = xKey[len - 1]; |
| |
| do |
| { |
| x = piTable[(x + xKey[index++]) & 255] & 0xff; |
| xKey[len++] = x; |
| } |
| while (len < 128); |
| } |
| |
| // Phase 2 - reduce effective key size to "bits" |
| len = (bits + 7) >> 3; |
| x = piTable[xKey[128 - len] & (255 >> (7 & -bits))] & 0xff; |
| xKey[128 - len] = x; |
| |
| for (int i = 128 - len - 1; i >= 0; i--) |
| { |
| x = piTable[x ^ xKey[i + len]] & 0xff; |
| xKey[i] = x; |
| } |
| |
| // Phase 3 - copy to newKey in little-endian order |
| int[] newKey = new int[64]; |
| |
| for (int i = 0; i != newKey.length; i++) |
| { |
| newKey[i] = (xKey[2 * i] + (xKey[2 * i + 1] << 8)); |
| } |
| |
| return newKey; |
| } |
| |
| /** |
| * initialise a RC2 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) |
| { |
| this.encrypting = encrypting; |
| |
| if (params instanceof RC2Parameters) |
| { |
| RC2Parameters param = (RC2Parameters)params; |
| |
| workingKey = generateWorkingKey(param.getKey(), |
| param.getEffectiveKeyBits()); |
| } |
| else if (params instanceof KeyParameter) |
| { |
| byte[] key = ((KeyParameter)params).getKey(); |
| |
| workingKey = generateWorkingKey(key, key.length * 8); |
| } |
| else |
| { |
| throw new IllegalArgumentException("invalid parameter passed to RC2 init - " + params.getClass().getName()); |
| } |
| |
| } |
| |
| public void reset() |
| { |
| } |
| |
| public String getAlgorithmName() |
| { |
| return "RC2"; |
| } |
| |
| public int getBlockSize() |
| { |
| return BLOCK_SIZE; |
| } |
| |
| public final int processBlock( |
| byte[] in, |
| int inOff, |
| byte[] out, |
| int outOff) |
| { |
| if (workingKey == null) |
| { |
| throw new IllegalStateException("RC2 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; |
| } |
| |
| /** |
| * return the result rotating the 16 bit number in x left by y |
| */ |
| private int rotateWordLeft( |
| int x, |
| int y) |
| { |
| x &= 0xffff; |
| return (x << y) | (x >> (16 - y)); |
| } |
| |
| private void encryptBlock( |
| byte[] in, |
| int inOff, |
| byte[] out, |
| int outOff) |
| { |
| int x76, x54, x32, x10; |
| |
| x76 = ((in[inOff + 7] & 0xff) << 8) + (in[inOff + 6] & 0xff); |
| x54 = ((in[inOff + 5] & 0xff) << 8) + (in[inOff + 4] & 0xff); |
| x32 = ((in[inOff + 3] & 0xff) << 8) + (in[inOff + 2] & 0xff); |
| x10 = ((in[inOff + 1] & 0xff) << 8) + (in[inOff + 0] & 0xff); |
| |
| for (int i = 0; i <= 16; i += 4) |
| { |
| x10 = rotateWordLeft(x10 + (x32 & ~x76) + (x54 & x76) + workingKey[i ], 1); |
| x32 = rotateWordLeft(x32 + (x54 & ~x10) + (x76 & x10) + workingKey[i+1], 2); |
| x54 = rotateWordLeft(x54 + (x76 & ~x32) + (x10 & x32) + workingKey[i+2], 3); |
| x76 = rotateWordLeft(x76 + (x10 & ~x54) + (x32 & x54) + workingKey[i+3], 5); |
| } |
| |
| x10 += workingKey[x76 & 63]; |
| x32 += workingKey[x10 & 63]; |
| x54 += workingKey[x32 & 63]; |
| x76 += workingKey[x54 & 63]; |
| |
| for (int i = 20; i <= 40; i += 4) |
| { |
| x10 = rotateWordLeft(x10 + (x32 & ~x76) + (x54 & x76) + workingKey[i ], 1); |
| x32 = rotateWordLeft(x32 + (x54 & ~x10) + (x76 & x10) + workingKey[i+1], 2); |
| x54 = rotateWordLeft(x54 + (x76 & ~x32) + (x10 & x32) + workingKey[i+2], 3); |
| x76 = rotateWordLeft(x76 + (x10 & ~x54) + (x32 & x54) + workingKey[i+3], 5); |
| } |
| |
| x10 += workingKey[x76 & 63]; |
| x32 += workingKey[x10 & 63]; |
| x54 += workingKey[x32 & 63]; |
| x76 += workingKey[x54 & 63]; |
| |
| for (int i = 44; i < 64; i += 4) |
| { |
| x10 = rotateWordLeft(x10 + (x32 & ~x76) + (x54 & x76) + workingKey[i ], 1); |
| x32 = rotateWordLeft(x32 + (x54 & ~x10) + (x76 & x10) + workingKey[i+1], 2); |
| x54 = rotateWordLeft(x54 + (x76 & ~x32) + (x10 & x32) + workingKey[i+2], 3); |
| x76 = rotateWordLeft(x76 + (x10 & ~x54) + (x32 & x54) + workingKey[i+3], 5); |
| } |
| |
| out[outOff + 0] = (byte)x10; |
| out[outOff + 1] = (byte)(x10 >> 8); |
| out[outOff + 2] = (byte)x32; |
| out[outOff + 3] = (byte)(x32 >> 8); |
| out[outOff + 4] = (byte)x54; |
| out[outOff + 5] = (byte)(x54 >> 8); |
| out[outOff + 6] = (byte)x76; |
| out[outOff + 7] = (byte)(x76 >> 8); |
| } |
| |
| private void decryptBlock( |
| byte[] in, |
| int inOff, |
| byte[] out, |
| int outOff) |
| { |
| int x76, x54, x32, x10; |
| |
| x76 = ((in[inOff + 7] & 0xff) << 8) + (in[inOff + 6] & 0xff); |
| x54 = ((in[inOff + 5] & 0xff) << 8) + (in[inOff + 4] & 0xff); |
| x32 = ((in[inOff + 3] & 0xff) << 8) + (in[inOff + 2] & 0xff); |
| x10 = ((in[inOff + 1] & 0xff) << 8) + (in[inOff + 0] & 0xff); |
| |
| for (int i = 60; i >= 44; i -= 4) |
| { |
| x76 = rotateWordLeft(x76, 11) - ((x10 & ~x54) + (x32 & x54) + workingKey[i+3]); |
| x54 = rotateWordLeft(x54, 13) - ((x76 & ~x32) + (x10 & x32) + workingKey[i+2]); |
| x32 = rotateWordLeft(x32, 14) - ((x54 & ~x10) + (x76 & x10) + workingKey[i+1]); |
| x10 = rotateWordLeft(x10, 15) - ((x32 & ~x76) + (x54 & x76) + workingKey[i ]); |
| } |
| |
| x76 -= workingKey[x54 & 63]; |
| x54 -= workingKey[x32 & 63]; |
| x32 -= workingKey[x10 & 63]; |
| x10 -= workingKey[x76 & 63]; |
| |
| for (int i = 40; i >= 20; i -= 4) |
| { |
| x76 = rotateWordLeft(x76, 11) - ((x10 & ~x54) + (x32 & x54) + workingKey[i+3]); |
| x54 = rotateWordLeft(x54, 13) - ((x76 & ~x32) + (x10 & x32) + workingKey[i+2]); |
| x32 = rotateWordLeft(x32, 14) - ((x54 & ~x10) + (x76 & x10) + workingKey[i+1]); |
| x10 = rotateWordLeft(x10, 15) - ((x32 & ~x76) + (x54 & x76) + workingKey[i ]); |
| } |
| |
| x76 -= workingKey[x54 & 63]; |
| x54 -= workingKey[x32 & 63]; |
| x32 -= workingKey[x10 & 63]; |
| x10 -= workingKey[x76 & 63]; |
| |
| for (int i = 16; i >= 0; i -= 4) |
| { |
| x76 = rotateWordLeft(x76, 11) - ((x10 & ~x54) + (x32 & x54) + workingKey[i+3]); |
| x54 = rotateWordLeft(x54, 13) - ((x76 & ~x32) + (x10 & x32) + workingKey[i+2]); |
| x32 = rotateWordLeft(x32, 14) - ((x54 & ~x10) + (x76 & x10) + workingKey[i+1]); |
| x10 = rotateWordLeft(x10, 15) - ((x32 & ~x76) + (x54 & x76) + workingKey[i ]); |
| } |
| |
| out[outOff + 0] = (byte)x10; |
| out[outOff + 1] = (byte)(x10 >> 8); |
| out[outOff + 2] = (byte)x32; |
| out[outOff + 3] = (byte)(x32 >> 8); |
| out[outOff + 4] = (byte)x54; |
| out[outOff + 5] = (byte)(x54 >> 8); |
| out[outOff + 6] = (byte)x76; |
| out[outOff + 7] = (byte)(x76 >> 8); |
| } |
| } |