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Diffstat (limited to 'libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/engines/TwofishEngine.java')
| -rw-r--r-- | libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/engines/TwofishEngine.java | 680 |
1 files changed, 680 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/engines/TwofishEngine.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/engines/TwofishEngine.java new file mode 100644 index 000000000..c5b843850 --- /dev/null +++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/engines/TwofishEngine.java @@ -0,0 +1,680 @@ +package org.spongycastle.crypto.engines; + +import org.spongycastle.crypto.BlockCipher; +import org.spongycastle.crypto.CipherParameters; +import org.spongycastle.crypto.DataLengthException; +import org.spongycastle.crypto.OutputLengthException; +import org.spongycastle.crypto.params.KeyParameter; + +/** + * A class that provides Twofish encryption operations. + * + * This Java implementation is based on the Java reference + * implementation provided by Bruce Schneier and developed + * by Raif S. Naffah. + */ +public final class TwofishEngine + implements BlockCipher +{ + private static final byte[][] P = { + { // p0 + (byte) 0xA9, (byte) 0x67, (byte) 0xB3, (byte) 0xE8, + (byte) 0x04, (byte) 0xFD, (byte) 0xA3, (byte) 0x76, + (byte) 0x9A, (byte) 0x92, (byte) 0x80, (byte) 0x78, + (byte) 0xE4, (byte) 0xDD, (byte) 0xD1, (byte) 0x38, + (byte) 0x0D, (byte) 0xC6, (byte) 0x35, (byte) 0x98, + (byte) 0x18, (byte) 0xF7, (byte) 0xEC, (byte) 0x6C, + (byte) 0x43, (byte) 0x75, (byte) 0x37, (byte) 0x26, + (byte) 0xFA, (byte) 0x13, (byte) 0x94, (byte) 0x48, + (byte) 0xF2, (byte) 0xD0, (byte) 0x8B, (byte) 0x30, + (byte) 0x84, (byte) 0x54, (byte) 0xDF, (byte) 0x23, + (byte) 0x19, (byte) 0x5B, (byte) 0x3D, (byte) 0x59, + (byte) 0xF3, (byte) 0xAE, (byte) 0xA2, (byte) 0x82, + (byte) 0x63, (byte) 0x01, (byte) 0x83, (byte) 0x2E, + (byte) 0xD9, (byte) 0x51, (byte) 0x9B, (byte) 0x7C, + (byte) 0xA6, (byte) 0xEB, (byte) 0xA5, (byte) 0xBE, + (byte) 0x16, (byte) 0x0C, (byte) 0xE3, (byte) 0x61, + (byte) 0xC0, (byte) 0x8C, (byte) 0x3A, (byte) 0xF5, + (byte) 0x73, (byte) 0x2C, (byte) 0x25, (byte) 0x0B, + (byte) 0xBB, (byte) 0x4E, (byte) 0x89, (byte) 0x6B, + (byte) 0x53, (byte) 0x6A, (byte) 0xB4, (byte) 0xF1, + (byte) 0xE1, (byte) 0xE6, (byte) 0xBD, (byte) 0x45, + (byte) 0xE2, (byte) 0xF4, (byte) 0xB6, (byte) 0x66, + (byte) 0xCC, (byte) 0x95, (byte) 0x03, (byte) 0x56, + (byte) 0xD4, (byte) 0x1C, (byte) 0x1E, (byte) 0xD7, + (byte) 0xFB, (byte) 0xC3, (byte) 0x8E, (byte) 0xB5, + (byte) 0xE9, (byte) 0xCF, (byte) 0xBF, (byte) 0xBA, + (byte) 0xEA, (byte) 0x77, (byte) 0x39, (byte) 0xAF, + (byte) 0x33, (byte) 0xC9, (byte) 0x62, (byte) 0x71, + (byte) 0x81, (byte) 0x79, (byte) 0x09, (byte) 0xAD, + (byte) 0x24, (byte) 0xCD, (byte) 0xF9, (byte) 0xD8, + (byte) 0xE5, (byte) 0xC5, (byte) 0xB9, (byte) 0x4D, + (byte) 0x44, (byte) 0x08, (byte) 0x86, (byte) 0xE7, + (byte) 0xA1, (byte) 0x1D, (byte) 0xAA, (byte) 0xED, + (byte) 0x06, (byte) 0x70, (byte) 0xB2, (byte) 0xD2, + (byte) 0x41, (byte) 0x7B, (byte) 0xA0, (byte) 0x11, + (byte) 0x31, (byte) 0xC2, (byte) 0x27, (byte) 0x90, + (byte) 0x20, (byte) 0xF6, (byte) 0x60, (byte) 0xFF, + (byte) 0x96, (byte) 0x5C, (byte) 0xB1, (byte) 0xAB, + (byte) 0x9E, (byte) 0x9C, (byte) 0x52, (byte) 0x1B, + (byte) 0x5F, (byte) 0x93, (byte) 0x0A, (byte) 0xEF, + (byte) 0x91, (byte) 0x85, (byte) 0x49, (byte) 0xEE, + (byte) 0x2D, (byte) 0x4F, (byte) 0x8F, (byte) 0x3B, + (byte) 0x47, (byte) 0x87, (byte) 0x6D, (byte) 0x46, + (byte) 0xD6, (byte) 0x3E, (byte) 0x69, (byte) 0x64, + (byte) 0x2A, (byte) 0xCE, (byte) 0xCB, (byte) 0x2F, + (byte) 0xFC, (byte) 0x97, (byte) 0x05, (byte) 0x7A, + (byte) 0xAC, (byte) 0x7F, (byte) 0xD5, (byte) 0x1A, + (byte) 0x4B, (byte) 0x0E, (byte) 0xA7, (byte) 0x5A, + (byte) 0x28, (byte) 0x14, (byte) 0x3F, (byte) 0x29, + (byte) 0x88, (byte) 0x3C, (byte) 0x4C, (byte) 0x02, + (byte) 0xB8, (byte) 0xDA, (byte) 0xB0, (byte) 0x17, + (byte) 0x55, (byte) 0x1F, (byte) 0x8A, (byte) 0x7D, + (byte) 0x57, (byte) 0xC7, (byte) 0x8D, (byte) 0x74, + (byte) 0xB7, (byte) 0xC4, (byte) 0x9F, (byte) 0x72, + (byte) 0x7E, (byte) 0x15, (byte) 0x22, (byte) 0x12, + (byte) 0x58, (byte) 0x07, (byte) 0x99, (byte) 0x34, + (byte) 0x6E, (byte) 0x50, (byte) 0xDE, (byte) 0x68, + (byte) 0x65, (byte) 0xBC, (byte) 0xDB, (byte) 0xF8, + (byte) 0xC8, (byte) 0xA8, (byte) 0x2B, (byte) 0x40, + (byte) 0xDC, (byte) 0xFE, (byte) 0x32, (byte) 0xA4, + (byte) 0xCA, (byte) 0x10, (byte) 0x21, (byte) 0xF0, + (byte) 0xD3, (byte) 0x5D, (byte) 0x0F, (byte) 0x00, + (byte) 0x6F, (byte) 0x9D, (byte) 0x36, (byte) 0x42, + (byte) 0x4A, (byte) 0x5E, (byte) 0xC1, (byte) 0xE0 }, + { // p1 + (byte) 0x75, (byte) 0xF3, (byte) 0xC6, (byte) 0xF4, + (byte) 0xDB, (byte) 0x7B, (byte) 0xFB, (byte) 0xC8, + (byte) 0x4A, (byte) 0xD3, (byte) 0xE6, (byte) 0x6B, + (byte) 0x45, (byte) 0x7D, (byte) 0xE8, (byte) 0x4B, + (byte) 0xD6, (byte) 0x32, (byte) 0xD8, (byte) 0xFD, + (byte) 0x37, (byte) 0x71, (byte) 0xF1, (byte) 0xE1, + (byte) 0x30, (byte) 0x0F, (byte) 0xF8, (byte) 0x1B, + (byte) 0x87, (byte) 0xFA, (byte) 0x06, (byte) 0x3F, + (byte) 0x5E, (byte) 0xBA, (byte) 0xAE, (byte) 0x5B, + (byte) 0x8A, (byte) 0x00, (byte) 0xBC, (byte) 0x9D, + (byte) 0x6D, (byte) 0xC1, (byte) 0xB1, (byte) 0x0E, + (byte) 0x80, (byte) 0x5D, (byte) 0xD2, (byte) 0xD5, + (byte) 0xA0, (byte) 0x84, (byte) 0x07, (byte) 0x14, + (byte) 0xB5, (byte) 0x90, (byte) 0x2C, (byte) 0xA3, + (byte) 0xB2, (byte) 0x73, (byte) 0x4C, (byte) 0x54, + (byte) 0x92, (byte) 0x74, (byte) 0x36, (byte) 0x51, + (byte) 0x38, (byte) 0xB0, (byte) 0xBD, (byte) 0x5A, + (byte) 0xFC, (byte) 0x60, (byte) 0x62, (byte) 0x96, + (byte) 0x6C, (byte) 0x42, (byte) 0xF7, (byte) 0x10, + (byte) 0x7C, (byte) 0x28, (byte) 0x27, (byte) 0x8C, + (byte) 0x13, (byte) 0x95, (byte) 0x9C, (byte) 0xC7, + (byte) 0x24, (byte) 0x46, (byte) 0x3B, (byte) 0x70, + (byte) 0xCA, (byte) 0xE3, (byte) 0x85, (byte) 0xCB, + (byte) 0x11, (byte) 0xD0, (byte) 0x93, (byte) 0xB8, + (byte) 0xA6, (byte) 0x83, (byte) 0x20, (byte) 0xFF, + (byte) 0x9F, (byte) 0x77, (byte) 0xC3, (byte) 0xCC, + (byte) 0x03, (byte) 0x6F, (byte) 0x08, (byte) 0xBF, + (byte) 0x40, (byte) 0xE7, (byte) 0x2B, (byte) 0xE2, + (byte) 0x79, (byte) 0x0C, (byte) 0xAA, (byte) 0x82, + (byte) 0x41, (byte) 0x3A, (byte) 0xEA, (byte) 0xB9, + (byte) 0xE4, (byte) 0x9A, (byte) 0xA4, (byte) 0x97, + (byte) 0x7E, (byte) 0xDA, (byte) 0x7A, (byte) 0x17, + (byte) 0x66, (byte) 0x94, (byte) 0xA1, (byte) 0x1D, + (byte) 0x3D, (byte) 0xF0, (byte) 0xDE, (byte) 0xB3, + (byte) 0x0B, (byte) 0x72, (byte) 0xA7, (byte) 0x1C, + (byte) 0xEF, (byte) 0xD1, (byte) 0x53, (byte) 0x3E, + (byte) 0x8F, (byte) 0x33, (byte) 0x26, (byte) 0x5F, + (byte) 0xEC, (byte) 0x76, (byte) 0x2A, (byte) 0x49, + (byte) 0x81, (byte) 0x88, (byte) 0xEE, (byte) 0x21, + (byte) 0xC4, (byte) 0x1A, (byte) 0xEB, (byte) 0xD9, + (byte) 0xC5, (byte) 0x39, (byte) 0x99, (byte) 0xCD, + (byte) 0xAD, (byte) 0x31, (byte) 0x8B, (byte) 0x01, + (byte) 0x18, (byte) 0x23, (byte) 0xDD, (byte) 0x1F, + (byte) 0x4E, (byte) 0x2D, (byte) 0xF9, (byte) 0x48, + (byte) 0x4F, (byte) 0xF2, (byte) 0x65, (byte) 0x8E, + (byte) 0x78, (byte) 0x5C, (byte) 0x58, (byte) 0x19, + (byte) 0x8D, (byte) 0xE5, (byte) 0x98, (byte) 0x57, + (byte) 0x67, (byte) 0x7F, (byte) 0x05, (byte) 0x64, + (byte) 0xAF, (byte) 0x63, (byte) 0xB6, (byte) 0xFE, + (byte) 0xF5, (byte) 0xB7, (byte) 0x3C, (byte) 0xA5, + (byte) 0xCE, (byte) 0xE9, (byte) 0x68, (byte) 0x44, + (byte) 0xE0, (byte) 0x4D, (byte) 0x43, (byte) 0x69, + (byte) 0x29, (byte) 0x2E, (byte) 0xAC, (byte) 0x15, + (byte) 0x59, (byte) 0xA8, (byte) 0x0A, (byte) 0x9E, + (byte) 0x6E, (byte) 0x47, (byte) 0xDF, (byte) 0x34, + (byte) 0x35, (byte) 0x6A, (byte) 0xCF, (byte) 0xDC, + (byte) 0x22, (byte) 0xC9, (byte) 0xC0, (byte) 0x9B, + (byte) 0x89, (byte) 0xD4, (byte) 0xED, (byte) 0xAB, + (byte) 0x12, (byte) 0xA2, (byte) 0x0D, (byte) 0x52, + (byte) 0xBB, (byte) 0x02, (byte) 0x2F, (byte) 0xA9, + (byte) 0xD7, (byte) 0x61, (byte) 0x1E, (byte) 0xB4, + (byte) 0x50, (byte) 0x04, (byte) 0xF6, (byte) 0xC2, + (byte) 0x16, (byte) 0x25, (byte) 0x86, (byte) 0x56, + (byte) 0x55, (byte) 0x09, (byte) 0xBE, (byte) 0x91 } + }; + + /** + * Define the fixed p0/p1 permutations used in keyed S-box lookup. + * By changing the following constant definitions, the S-boxes will + * automatically get changed in the Twofish engine. + */ + private static final int P_00 = 1; + private static final int P_01 = 0; + private static final int P_02 = 0; + private static final int P_03 = P_01 ^ 1; + private static final int P_04 = 1; + + private static final int P_10 = 0; + private static final int P_11 = 0; + private static final int P_12 = 1; + private static final int P_13 = P_11 ^ 1; + private static final int P_14 = 0; + + private static final int P_20 = 1; + private static final int P_21 = 1; + private static final int P_22 = 0; + private static final int P_23 = P_21 ^ 1; + private static final int P_24 = 0; + + private static final int P_30 = 0; + private static final int P_31 = 1; + private static final int P_32 = 1; + private static final int P_33 = P_31 ^ 1; + private static final int P_34 = 1; + + /* Primitive polynomial for GF(256) */ + private static final int GF256_FDBK = 0x169; + private static final int GF256_FDBK_2 = GF256_FDBK / 2; + private static final int GF256_FDBK_4 = GF256_FDBK / 4; + + private static final int RS_GF_FDBK = 0x14D; // field generator + + //==================================== + // Useful constants + //==================================== + + private static final int ROUNDS = 16; + private static final int MAX_ROUNDS = 16; // bytes = 128 bits + private static final int BLOCK_SIZE = 16; // bytes = 128 bits + private static final int MAX_KEY_BITS = 256; + + private static final int INPUT_WHITEN=0; + private static final int OUTPUT_WHITEN=INPUT_WHITEN+BLOCK_SIZE/4; // 4 + private static final int ROUND_SUBKEYS=OUTPUT_WHITEN+BLOCK_SIZE/4;// 8 + + private static final int TOTAL_SUBKEYS=ROUND_SUBKEYS+2*MAX_ROUNDS;// 40 + + private static final int SK_STEP = 0x02020202; + private static final int SK_BUMP = 0x01010101; + private static final int SK_ROTL = 9; + + private boolean encrypting = false; + + private int[] gMDS0 = new int[MAX_KEY_BITS]; + private int[] gMDS1 = new int[MAX_KEY_BITS]; + private int[] gMDS2 = new int[MAX_KEY_BITS]; + private int[] gMDS3 = new int[MAX_KEY_BITS]; + + /** + * gSubKeys[] and gSBox[] are eventually used in the + * encryption and decryption methods. + */ + private int[] gSubKeys; + private int[] gSBox; + + private int k64Cnt = 0; + + private byte[] workingKey = null; + + public TwofishEngine() + { + // calculate the MDS matrix + int[] m1 = new int[2]; + int[] mX = new int[2]; + int[] mY = new int[2]; + int j; + + for (int i=0; i< MAX_KEY_BITS ; i++) + { + j = P[0][i] & 0xff; + m1[0] = j; + mX[0] = Mx_X(j) & 0xff; + mY[0] = Mx_Y(j) & 0xff; + + j = P[1][i] & 0xff; + m1[1] = j; + mX[1] = Mx_X(j) & 0xff; + mY[1] = Mx_Y(j) & 0xff; + + gMDS0[i] = m1[P_00] | mX[P_00] << 8 | + mY[P_00] << 16 | mY[P_00] << 24; + + gMDS1[i] = mY[P_10] | mY[P_10] << 8 | + mX[P_10] << 16 | m1[P_10] << 24; + + gMDS2[i] = mX[P_20] | mY[P_20] << 8 | + m1[P_20] << 16 | mY[P_20] << 24; + + gMDS3[i] = mX[P_30] | m1[P_30] << 8 | + mY[P_30] << 16 | mX[P_30] << 24; + } + } + + /** + * initialise a Twofish 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) + { + this.encrypting = encrypting; + this.workingKey = ((KeyParameter)params).getKey(); + this.k64Cnt = (this.workingKey.length / 8); // pre-padded ? + setKey(this.workingKey); + + return; + } + + throw new IllegalArgumentException("invalid parameter passed to Twofish init - " + params.getClass().getName()); + } + + public String getAlgorithmName() + { + return "Twofish"; + } + + public int processBlock( + byte[] in, + int inOff, + byte[] out, + int outOff) + { + if (workingKey == null) + { + throw new IllegalStateException("Twofish 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() + { + if (this.workingKey != null) + { + setKey(this.workingKey); + } + } + + public int getBlockSize() + { + return BLOCK_SIZE; + } + + //================================== + // Private Implementation + //================================== + + private void setKey(byte[] key) + { + int[] k32e = new int[MAX_KEY_BITS/64]; // 4 + int[] k32o = new int[MAX_KEY_BITS/64]; // 4 + + int[] sBoxKeys = new int[MAX_KEY_BITS/64]; // 4 + gSubKeys = new int[TOTAL_SUBKEYS]; + + if (k64Cnt < 1) + { + throw new IllegalArgumentException("Key size less than 64 bits"); + } + + if (k64Cnt > 4) + { + throw new IllegalArgumentException("Key size larger than 256 bits"); + } + + /* + * k64Cnt is the number of 8 byte blocks (64 chunks) + * that are in the input key. The input key is a + * maximum of 32 bytes (256 bits), so the range + * for k64Cnt is 1..4 + */ + for (int i=0; i<k64Cnt ; i++) + { + int p = i* 8; + + k32e[i] = BytesTo32Bits(key, p); + k32o[i] = BytesTo32Bits(key, p+4); + + sBoxKeys[k64Cnt-1-i] = RS_MDS_Encode(k32e[i], k32o[i]); + } + + int q,A,B; + for (int i=0; i < TOTAL_SUBKEYS / 2 ; i++) + { + q = i*SK_STEP; + A = F32(q, k32e); + B = F32(q+SK_BUMP, k32o); + B = B << 8 | B >>> 24; + A += B; + gSubKeys[i*2] = A; + A += B; + gSubKeys[i*2 + 1] = A << SK_ROTL | A >>> (32-SK_ROTL); + } + + /* + * fully expand the table for speed + */ + int k0 = sBoxKeys[0]; + int k1 = sBoxKeys[1]; + int k2 = sBoxKeys[2]; + int k3 = sBoxKeys[3]; + int b0, b1, b2, b3; + gSBox = new int[4*MAX_KEY_BITS]; + for (int i=0; i<MAX_KEY_BITS; i++) + { + b0 = b1 = b2 = b3 = i; + switch (k64Cnt & 3) + { + case 1: + gSBox[i*2] = gMDS0[(P[P_01][b0] & 0xff) ^ b0(k0)]; + gSBox[i*2+1] = gMDS1[(P[P_11][b1] & 0xff) ^ b1(k0)]; + gSBox[i*2+0x200] = gMDS2[(P[P_21][b2] & 0xff) ^ b2(k0)]; + gSBox[i*2+0x201] = gMDS3[(P[P_31][b3] & 0xff) ^ b3(k0)]; + break; + case 0: // 256 bits of key + b0 = (P[P_04][b0] & 0xff) ^ b0(k3); + b1 = (P[P_14][b1] & 0xff) ^ b1(k3); + b2 = (P[P_24][b2] & 0xff) ^ b2(k3); + b3 = (P[P_34][b3] & 0xff) ^ b3(k3); + // fall through, having pre-processed b[0]..b[3] with k32[3] + case 3: // 192 bits of key + b0 = (P[P_03][b0] & 0xff) ^ b0(k2); + b1 = (P[P_13][b1] & 0xff) ^ b1(k2); + b2 = (P[P_23][b2] & 0xff) ^ b2(k2); + b3 = (P[P_33][b3] & 0xff) ^ b3(k2); + // fall through, having pre-processed b[0]..b[3] with k32[2] + case 2: // 128 bits of key + gSBox[i*2] = gMDS0[(P[P_01] + [(P[P_02][b0] & 0xff) ^ b0(k1)] & 0xff) ^ b0(k0)]; + gSBox[i*2+1] = gMDS1[(P[P_11] + [(P[P_12][b1] & 0xff) ^ b1(k1)] & 0xff) ^ b1(k0)]; + gSBox[i*2+0x200] = gMDS2[(P[P_21] + [(P[P_22][b2] & 0xff) ^ b2(k1)] & 0xff) ^ b2(k0)]; + gSBox[i*2+0x201] = gMDS3[(P[P_31] + [(P[P_32][b3] & 0xff) ^ b3(k1)] & 0xff) ^ b3(k0)]; + break; + } + } + + /* + * the function exits having setup the gSBox with the + * input key material. + */ + } + + /** + * Encrypt the given input starting at the given offset and place + * the result in the provided buffer starting at the given offset. + * The input will be an exact multiple of our blocksize. + * + * encryptBlock uses the pre-calculated gSBox[] and subKey[] + * arrays. + */ + private void encryptBlock( + byte[] src, + int srcIndex, + byte[] dst, + int dstIndex) + { + int x0 = BytesTo32Bits(src, srcIndex) ^ gSubKeys[INPUT_WHITEN]; + int x1 = BytesTo32Bits(src, srcIndex + 4) ^ gSubKeys[INPUT_WHITEN + 1]; + int x2 = BytesTo32Bits(src, srcIndex + 8) ^ gSubKeys[INPUT_WHITEN + 2]; + int x3 = BytesTo32Bits(src, srcIndex + 12) ^ gSubKeys[INPUT_WHITEN + 3]; + + int k = ROUND_SUBKEYS; + int t0, t1; + for (int r = 0; r < ROUNDS; r +=2) + { + t0 = Fe32_0(x0); + t1 = Fe32_3(x1); + x2 ^= t0 + t1 + gSubKeys[k++]; + x2 = x2 >>>1 | x2 << 31; + x3 = (x3 << 1 | x3 >>> 31) ^ (t0 + 2*t1 + gSubKeys[k++]); + + t0 = Fe32_0(x2); + t1 = Fe32_3(x3); + x0 ^= t0 + t1 + gSubKeys[k++]; + x0 = x0 >>>1 | x0 << 31; + x1 = (x1 << 1 | x1 >>> 31) ^ (t0 + 2*t1 + gSubKeys[k++]); + } + + Bits32ToBytes(x2 ^ gSubKeys[OUTPUT_WHITEN], dst, dstIndex); + Bits32ToBytes(x3 ^ gSubKeys[OUTPUT_WHITEN + 1], dst, dstIndex + 4); + Bits32ToBytes(x0 ^ gSubKeys[OUTPUT_WHITEN + 2], dst, dstIndex + 8); + Bits32ToBytes(x1 ^ gSubKeys[OUTPUT_WHITEN + 3], dst, dstIndex + 12); + } + + /** + * Decrypt the given input starting at the given offset and place + * the result in the provided buffer starting at the given offset. + * The input will be an exact multiple of our blocksize. + */ + private void decryptBlock( + byte[] src, + int srcIndex, + byte[] dst, + int dstIndex) + { + int x2 = BytesTo32Bits(src, srcIndex) ^ gSubKeys[OUTPUT_WHITEN]; + int x3 = BytesTo32Bits(src, srcIndex+4) ^ gSubKeys[OUTPUT_WHITEN + 1]; + int x0 = BytesTo32Bits(src, srcIndex+8) ^ gSubKeys[OUTPUT_WHITEN + 2]; + int x1 = BytesTo32Bits(src, srcIndex+12) ^ gSubKeys[OUTPUT_WHITEN + 3]; + + int k = ROUND_SUBKEYS + 2 * ROUNDS -1 ; + int t0, t1; + for (int r = 0; r< ROUNDS ; r +=2) + { + t0 = Fe32_0(x2); + t1 = Fe32_3(x3); + x1 ^= t0 + 2*t1 + gSubKeys[k--]; + x0 = (x0 << 1 | x0 >>> 31) ^ (t0 + t1 + gSubKeys[k--]); + x1 = x1 >>>1 | x1 << 31; + + t0 = Fe32_0(x0); + t1 = Fe32_3(x1); + x3 ^= t0 + 2*t1 + gSubKeys[k--]; + x2 = (x2 << 1 | x2 >>> 31) ^ (t0 + t1 + gSubKeys[k--]); + x3 = x3 >>>1 | x3 << 31; + } + + Bits32ToBytes(x0 ^ gSubKeys[INPUT_WHITEN], dst, dstIndex); + Bits32ToBytes(x1 ^ gSubKeys[INPUT_WHITEN + 1], dst, dstIndex + 4); + Bits32ToBytes(x2 ^ gSubKeys[INPUT_WHITEN + 2], dst, dstIndex + 8); + Bits32ToBytes(x3 ^ gSubKeys[INPUT_WHITEN + 3], dst, dstIndex + 12); + } + + /* + * TODO: This can be optimised and made cleaner by combining + * the functionality in this function and applying it appropriately + * to the creation of the subkeys during key setup. + */ + private int F32(int x, int[] k32) + { + int b0 = b0(x); + int b1 = b1(x); + int b2 = b2(x); + int b3 = b3(x); + int k0 = k32[0]; + int k1 = k32[1]; + int k2 = k32[2]; + int k3 = k32[3]; + + int result = 0; + switch (k64Cnt & 3) + { + case 1: + result = gMDS0[(P[P_01][b0] & 0xff) ^ b0(k0)] ^ + gMDS1[(P[P_11][b1] & 0xff) ^ b1(k0)] ^ + gMDS2[(P[P_21][b2] & 0xff) ^ b2(k0)] ^ + gMDS3[(P[P_31][b3] & 0xff) ^ b3(k0)]; + break; + case 0: /* 256 bits of key */ + b0 = (P[P_04][b0] & 0xff) ^ b0(k3); + b1 = (P[P_14][b1] & 0xff) ^ b1(k3); + b2 = (P[P_24][b2] & 0xff) ^ b2(k3); + b3 = (P[P_34][b3] & 0xff) ^ b3(k3); + case 3: + b0 = (P[P_03][b0] & 0xff) ^ b0(k2); + b1 = (P[P_13][b1] & 0xff) ^ b1(k2); + b2 = (P[P_23][b2] & 0xff) ^ b2(k2); + b3 = (P[P_33][b3] & 0xff) ^ b3(k2); + case 2: + result = + gMDS0[(P[P_01][(P[P_02][b0]&0xff)^b0(k1)]&0xff)^b0(k0)] ^ + gMDS1[(P[P_11][(P[P_12][b1]&0xff)^b1(k1)]&0xff)^b1(k0)] ^ + gMDS2[(P[P_21][(P[P_22][b2]&0xff)^b2(k1)]&0xff)^b2(k0)] ^ + gMDS3[(P[P_31][(P[P_32][b3]&0xff)^b3(k1)]&0xff)^b3(k0)]; + break; + } + return result; + } + + /** + * Use (12, 8) Reed-Solomon code over GF(256) to produce + * a key S-box 32-bit entity from 2 key material 32-bit + * entities. + * + * @param k0 first 32-bit entity + * @param k1 second 32-bit entity + * @return Remainder polynomial generated using RS code + */ + private int RS_MDS_Encode(int k0, int k1) + { + int r = k1; + for (int i = 0 ; i < 4 ; i++) // shift 1 byte at a time + { + r = RS_rem(r); + } + r ^= k0; + for (int i=0 ; i < 4 ; i++) + { + r = RS_rem(r); + } + + return r; + } + + /** + * Reed-Solomon code parameters: (12,8) reversible code:<p> + * <pre> + * g(x) = x^4 + (a+1/a)x^3 + ax^2 + (a+1/a)x + 1 + * </pre> + * where a = primitive root of field generator 0x14D + */ + private int RS_rem(int x) + { + int b = (x >>> 24) & 0xff; + int g2 = ((b << 1) ^ + ((b & 0x80) != 0 ? RS_GF_FDBK : 0)) & 0xff; + int g3 = ((b >>> 1) ^ + ((b & 0x01) != 0 ? (RS_GF_FDBK >>> 1) : 0)) ^ g2 ; + return ((x << 8) ^ (g3 << 24) ^ (g2 << 16) ^ (g3 << 8) ^ b); + } + + private int LFSR1(int x) + { + return (x >> 1) ^ + (((x & 0x01) != 0) ? GF256_FDBK_2 : 0); + } + + private int LFSR2(int x) + { + return (x >> 2) ^ + (((x & 0x02) != 0) ? GF256_FDBK_2 : 0) ^ + (((x & 0x01) != 0) ? GF256_FDBK_4 : 0); + } + + private int Mx_X(int x) + { + return x ^ LFSR2(x); + } // 5B + + private int Mx_Y(int x) + { + return x ^ LFSR1(x) ^ LFSR2(x); + } // EF + + private int b0(int x) + { + return x & 0xff; + } + + private int b1(int x) + { + return (x >>> 8) & 0xff; + } + + private int b2(int x) + { + return (x >>> 16) & 0xff; + } + + private int b3(int x) + { + return (x >>> 24) & 0xff; + } + + private int Fe32_0(int x) + { + return gSBox[ 0x000 + 2*(x & 0xff) ] ^ + gSBox[ 0x001 + 2*((x >>> 8) & 0xff) ] ^ + gSBox[ 0x200 + 2*((x >>> 16) & 0xff) ] ^ + gSBox[ 0x201 + 2*((x >>> 24) & 0xff) ]; + } + + private int Fe32_3(int x) + { + return gSBox[ 0x000 + 2*((x >>> 24) & 0xff) ] ^ + gSBox[ 0x001 + 2*(x & 0xff) ] ^ + gSBox[ 0x200 + 2*((x >>> 8) & 0xff) ] ^ + gSBox[ 0x201 + 2*((x >>> 16) & 0xff) ]; + } + + private int BytesTo32Bits(byte[] b, int p) + { + return ((b[p] & 0xff)) | + ((b[p+1] & 0xff) << 8) | + ((b[p+2] & 0xff) << 16) | + ((b[p+3] & 0xff) << 24); + } + + private void Bits32ToBytes(int in, byte[] b, int offset) + { + b[offset] = (byte)in; + b[offset + 1] = (byte)(in >> 8); + b[offset + 2] = (byte)(in >> 16); + b[offset + 3] = (byte)(in >> 24); + } +} |