1f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Projectpackage org.bouncycastle.crypto.modes; 2f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 3f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Projectimport org.bouncycastle.crypto.BlockCipher; 4f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Projectimport org.bouncycastle.crypto.CipherParameters; 5f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Projectimport org.bouncycastle.crypto.DataLengthException; 6f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Projectimport org.bouncycastle.crypto.params.ParametersWithIV; 7f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 8f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project/** 9f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * implements a Cipher-FeedBack (CFB) mode on top of a simple cipher. 10f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 11f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Projectpublic class CFBBlockCipher 12f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project implements BlockCipher 13f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project{ 14f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project private byte[] IV; 15f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project private byte[] cfbV; 16f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project private byte[] cfbOutV; 17f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 18f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project private int blockSize; 19f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project private BlockCipher cipher = null; 20f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project private boolean encrypting; 21f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 22f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 23f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Basic constructor. 24f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * 25f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param cipher the block cipher to be used as the basis of the 26f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * feedback mode. 27f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param bitBlockSize the block size in bits (note: a multiple of 8) 28f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 29f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public CFBBlockCipher( 30f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project BlockCipher cipher, 31f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project int bitBlockSize) 32f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 33f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project this.cipher = cipher; 34f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project this.blockSize = bitBlockSize / 8; 35f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 36f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project this.IV = new byte[cipher.getBlockSize()]; 37f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project this.cfbV = new byte[cipher.getBlockSize()]; 38f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project this.cfbOutV = new byte[cipher.getBlockSize()]; 39f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 40f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 41f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 42f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * return the underlying block cipher that we are wrapping. 43f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * 44f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @return the underlying block cipher that we are wrapping. 45f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 46f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public BlockCipher getUnderlyingCipher() 47f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 48f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project return cipher; 49f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 50f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 51f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 52f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Initialise the cipher and, possibly, the initialisation vector (IV). 53f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * If an IV isn't passed as part of the parameter, the IV will be all zeros. 54f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * An IV which is too short is handled in FIPS compliant fashion. 55f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * 56f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param encrypting if true the cipher is initialised for 57f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * encryption, if false for decryption. 58f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param params the key and other data required by the cipher. 59f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @exception IllegalArgumentException if the params argument is 60f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * inappropriate. 61f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 62f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public void init( 63f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project boolean encrypting, 64f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project CipherParameters params) 65f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project throws IllegalArgumentException 66f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 67f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project this.encrypting = encrypting; 68f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 69f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project if (params instanceof ParametersWithIV) 70f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 71f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project ParametersWithIV ivParam = (ParametersWithIV)params; 72f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project byte[] iv = ivParam.getIV(); 73f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 74f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project if (iv.length < IV.length) 75f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 76f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // prepend the supplied IV with zeros (per FIPS PUB 81) 77f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project System.arraycopy(iv, 0, IV, IV.length - iv.length, iv.length); 78f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project for (int i = 0; i < IV.length - iv.length; i++) 79f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 80f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project IV[i] = 0; 81f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 82f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 83f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project else 84f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 85f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project System.arraycopy(iv, 0, IV, 0, IV.length); 86f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 87f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 88f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project reset(); 89f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 90f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project cipher.init(true, ivParam.getParameters()); 91f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 92f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project else 93f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 94f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project reset(); 95f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 96f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project cipher.init(true, params); 97f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 98f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 99f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 100f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 101f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * return the algorithm name and mode. 102f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * 103f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @return the name of the underlying algorithm followed by "/CFB" 104f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * and the block size in bits. 105f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 106f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public String getAlgorithmName() 107f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 108f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project return cipher.getAlgorithmName() + "/CFB" + (blockSize * 8); 109f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 110f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 111f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 112f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * return the block size we are operating at. 113f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * 114f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @return the block size we are operating at (in bytes). 115f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 116f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public int getBlockSize() 117f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 118f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project return blockSize; 119f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 120f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 121f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 122f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Process one block of input from the array in and write it to 123f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * the out array. 124f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * 125f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param in the array containing the input data. 126f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param inOff offset into the in array the data starts at. 127f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param out the array the output data will be copied into. 128f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param outOff the offset into the out array the output will start at. 129f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @exception DataLengthException if there isn't enough data in in, or 130f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * space in out. 131f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @exception IllegalStateException if the cipher isn't initialised. 132f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @return the number of bytes processed and produced. 133f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 134f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public int processBlock( 135f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project byte[] in, 136f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project int inOff, 137f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project byte[] out, 138f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project int outOff) 139f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project throws DataLengthException, IllegalStateException 140f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 141f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project return (encrypting) ? encryptBlock(in, inOff, out, outOff) : decryptBlock(in, inOff, out, outOff); 142f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 143f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 144f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 145f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Do the appropriate processing for CFB mode encryption. 146f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * 147f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param in the array containing the data to be encrypted. 148f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param inOff offset into the in array the data starts at. 149f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param out the array the encrypted data will be copied into. 150f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param outOff the offset into the out array the output will start at. 151f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @exception DataLengthException if there isn't enough data in in, or 152f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * space in out. 153f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @exception IllegalStateException if the cipher isn't initialised. 154f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @return the number of bytes processed and produced. 155f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 156f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public int encryptBlock( 157f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project byte[] in, 158f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project int inOff, 159f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project byte[] out, 160f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project int outOff) 161f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project throws DataLengthException, IllegalStateException 162f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 163f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project if ((inOff + blockSize) > in.length) 164f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 165f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project throw new DataLengthException("input buffer too short"); 166f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 167f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 168f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project if ((outOff + blockSize) > out.length) 169f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 170f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project throw new DataLengthException("output buffer too short"); 171f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 172f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 173f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project cipher.processBlock(cfbV, 0, cfbOutV, 0); 174f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 175f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // 176f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // XOR the cfbV with the plaintext producing the cipher text 177f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // 178f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project for (int i = 0; i < blockSize; i++) 179f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 180f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project out[outOff + i] = (byte)(cfbOutV[i] ^ in[inOff + i]); 181f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 182f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 183f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // 184f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // change over the input block. 185f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // 186f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project System.arraycopy(cfbV, blockSize, cfbV, 0, cfbV.length - blockSize); 187f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project System.arraycopy(out, outOff, cfbV, cfbV.length - blockSize, blockSize); 188f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 189f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project return blockSize; 190f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 191f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 192f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 193f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Do the appropriate processing for CFB mode decryption. 194f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * 195f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param in the array containing the data to be decrypted. 196f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param inOff offset into the in array the data starts at. 197f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param out the array the encrypted data will be copied into. 198f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param outOff the offset into the out array the output will start at. 199f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @exception DataLengthException if there isn't enough data in in, or 200f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * space in out. 201f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @exception IllegalStateException if the cipher isn't initialised. 202f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @return the number of bytes processed and produced. 203f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 204f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public int decryptBlock( 205f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project byte[] in, 206f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project int inOff, 207f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project byte[] out, 208f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project int outOff) 209f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project throws DataLengthException, IllegalStateException 210f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 211f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project if ((inOff + blockSize) > in.length) 212f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 213f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project throw new DataLengthException("input buffer too short"); 214f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 215f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 216f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project if ((outOff + blockSize) > out.length) 217f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 218f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project throw new DataLengthException("output buffer too short"); 219f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 220f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 221f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project cipher.processBlock(cfbV, 0, cfbOutV, 0); 222f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 223f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // 224f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // change over the input block. 225f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // 226f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project System.arraycopy(cfbV, blockSize, cfbV, 0, cfbV.length - blockSize); 227f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project System.arraycopy(in, inOff, cfbV, cfbV.length - blockSize, blockSize); 228f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 229f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // 230f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // XOR the cfbV with the plaintext producing the plain text 231f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // 232f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project for (int i = 0; i < blockSize; i++) 233f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 234f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project out[outOff + i] = (byte)(cfbOutV[i] ^ in[inOff + i]); 235f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 236f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 237f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project return blockSize; 238f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 239f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 240f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 241f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * reset the chaining vector back to the IV and reset the underlying 242f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * cipher. 243f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 244f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public void reset() 245f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project { 246f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project System.arraycopy(IV, 0, cfbV, 0, IV.length); 247f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 248f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project cipher.reset(); 249f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 250f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project} 251