diff options
Diffstat (limited to 'core/src/main/java/org/bouncycastle/crypto/modes/GOFBBlockCipher.java')
| -rw-r--r-- | core/src/main/java/org/bouncycastle/crypto/modes/GOFBBlockCipher.java | 228 |
1 files changed, 0 insertions, 228 deletions
diff --git a/core/src/main/java/org/bouncycastle/crypto/modes/GOFBBlockCipher.java b/core/src/main/java/org/bouncycastle/crypto/modes/GOFBBlockCipher.java deleted file mode 100644 index b025a1b8..00000000 --- a/core/src/main/java/org/bouncycastle/crypto/modes/GOFBBlockCipher.java +++ /dev/null @@ -1,228 +0,0 @@ -package org.bouncycastle.crypto.modes; - -import org.bouncycastle.crypto.BlockCipher; -import org.bouncycastle.crypto.CipherParameters; -import org.bouncycastle.crypto.DataLengthException; -import org.bouncycastle.crypto.StreamBlockCipher; -import org.bouncycastle.crypto.params.ParametersWithIV; - -/** - * implements the GOST 28147 OFB counter mode (GCTR). - */ -public class GOFBBlockCipher - extends StreamBlockCipher -{ - private byte[] IV; - private byte[] ofbV; - private byte[] ofbOutV; - private int byteCount; - - private final int blockSize; - private final BlockCipher cipher; - - boolean firstStep = true; - int N3; - int N4; - static final int C1 = 16843012; //00000001000000010000000100000100 - static final int C2 = 16843009; //00000001000000010000000100000001 - - - /** - * Basic constructor. - * - * @param cipher the block cipher to be used as the basis of the - * counter mode (must have a 64 bit block size). - */ - public GOFBBlockCipher( - BlockCipher cipher) - { - super(cipher); - - this.cipher = cipher; - this.blockSize = cipher.getBlockSize(); - - if (blockSize != 8) - { - throw new IllegalArgumentException("GCTR only for 64 bit block ciphers"); - } - - this.IV = new byte[cipher.getBlockSize()]; - this.ofbV = new byte[cipher.getBlockSize()]; - this.ofbOutV = new byte[cipher.getBlockSize()]; - } - - /** - * Initialise the cipher and, possibly, the initialisation vector (IV). - * If an IV isn't passed as part of the parameter, the IV will be all zeros. - * An IV which is too short is handled in FIPS compliant fashion. - * - * @param encrypting if true the cipher is initialised for - * encryption, if false for decryption. - * @param params the key and other data required by the cipher. - * @exception IllegalArgumentException if the params argument is - * inappropriate. - */ - public void init( - boolean encrypting, //ignored by this CTR mode - CipherParameters params) - throws IllegalArgumentException - { - firstStep = true; - N3 = 0; - N4 = 0; - - if (params instanceof ParametersWithIV) - { - ParametersWithIV ivParam = (ParametersWithIV)params; - byte[] iv = ivParam.getIV(); - - if (iv.length < IV.length) - { - // prepend the supplied IV with zeros (per FIPS PUB 81) - System.arraycopy(iv, 0, IV, IV.length - iv.length, iv.length); - for (int i = 0; i < IV.length - iv.length; i++) - { - IV[i] = 0; - } - } - else - { - System.arraycopy(iv, 0, IV, 0, IV.length); - } - - reset(); - - // if params is null we reuse the current working key. - if (ivParam.getParameters() != null) - { - cipher.init(true, ivParam.getParameters()); - } - } - else - { - reset(); - - // if params is null we reuse the current working key. - if (params != null) - { - cipher.init(true, params); - } - } - } - - /** - * return the algorithm name and mode. - * - * @return the name of the underlying algorithm followed by "/GCTR" - * and the block size in bits - */ - public String getAlgorithmName() - { - return cipher.getAlgorithmName() + "/GCTR"; - } - - /** - * return the block size we are operating at (in bytes). - * - * @return the block size we are operating at (in bytes). - */ - public int getBlockSize() - { - return blockSize; - } - - /** - * Process one block of input from the array in and write it to - * the out array. - * - * @param in the array containing the input data. - * @param inOff offset into the in array the data starts at. - * @param out the array the output data will be copied into. - * @param outOff the offset into the out array the output will start at. - * @exception DataLengthException if there isn't enough data in in, or - * space in out. - * @exception IllegalStateException if the cipher isn't initialised. - * @return the number of bytes processed and produced. - */ - public int processBlock( - byte[] in, - int inOff, - byte[] out, - int outOff) - throws DataLengthException, IllegalStateException - { - processBytes(in, inOff, blockSize, out, outOff); - - return blockSize; - } - - /** - * reset the feedback vector back to the IV and reset the underlying - * cipher. - */ - public void reset() - { - firstStep = true; - N3 = 0; - N4 = 0; - System.arraycopy(IV, 0, ofbV, 0, IV.length); - byteCount = 0; - cipher.reset(); - } - - //array of bytes to type int - private int bytesToint( - byte[] in, - int inOff) - { - return ((in[inOff + 3] << 24) & 0xff000000) + ((in[inOff + 2] << 16) & 0xff0000) + - ((in[inOff + 1] << 8) & 0xff00) + (in[inOff] & 0xff); - } - - //int to array of bytes - private void intTobytes( - int num, - byte[] out, - int outOff) - { - out[outOff + 3] = (byte)(num >>> 24); - out[outOff + 2] = (byte)(num >>> 16); - out[outOff + 1] = (byte)(num >>> 8); - out[outOff] = (byte)num; - } - - protected byte calculateByte(byte b) - { - if (byteCount == 0) - { - if (firstStep) - { - firstStep = false; - cipher.processBlock(ofbV, 0, ofbOutV, 0); - N3 = bytesToint(ofbOutV, 0); - N4 = bytesToint(ofbOutV, 4); - } - N3 += C2; - N4 += C1; - intTobytes(N3, ofbV, 0); - intTobytes(N4, ofbV, 4); - - cipher.processBlock(ofbV, 0, ofbOutV, 0); - } - - byte rv = (byte)(ofbOutV[byteCount++] ^ b); - - if (byteCount == blockSize) - { - byteCount = 0; - - // - // change over the input block. - // - System.arraycopy(ofbV, blockSize, ofbV, 0, ofbV.length - blockSize); - System.arraycopy(ofbOutV, 0, ofbV, ofbV.length - blockSize, blockSize); - } - - return rv; - } -} |