diff options
Diffstat (limited to 'core/src/main/java/org/bouncycastle/crypto/modes/CFBBlockCipher.java')
| -rw-r--r-- | core/src/main/java/org/bouncycastle/crypto/modes/CFBBlockCipher.java | 269 |
1 files changed, 0 insertions, 269 deletions
diff --git a/core/src/main/java/org/bouncycastle/crypto/modes/CFBBlockCipher.java b/core/src/main/java/org/bouncycastle/crypto/modes/CFBBlockCipher.java deleted file mode 100644 index 6167d256..00000000 --- a/core/src/main/java/org/bouncycastle/crypto/modes/CFBBlockCipher.java +++ /dev/null @@ -1,269 +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; -import org.bouncycastle.util.Arrays; - -/** - * implements a Cipher-FeedBack (CFB) mode on top of a simple cipher. - */ -public class CFBBlockCipher - extends StreamBlockCipher -{ - private byte[] IV; - private byte[] cfbV; - private byte[] cfbOutV; - private byte[] inBuf; - - private int blockSize; - private BlockCipher cipher = null; - private boolean encrypting; - private int byteCount; - - /** - * Basic constructor. - * - * @param cipher the block cipher to be used as the basis of the - * feedback mode. - * @param bitBlockSize the block size in bits (note: a multiple of 8) - */ - public CFBBlockCipher( - BlockCipher cipher, - int bitBlockSize) - { - super(cipher); - - this.cipher = cipher; - this.blockSize = bitBlockSize / 8; - - this.IV = new byte[cipher.getBlockSize()]; - this.cfbV = new byte[cipher.getBlockSize()]; - this.cfbOutV = new byte[cipher.getBlockSize()]; - this.inBuf = new byte[blockSize]; - } - - /** - * 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, - CipherParameters params) - throws IllegalArgumentException - { - this.encrypting = encrypting; - - 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 null it's an IV changed only. - if (ivParam.getParameters() != null) - { - cipher.init(true, ivParam.getParameters()); - } - } - else - { - reset(); - - // if it's null, key is to be reused. - if (params != null) - { - cipher.init(true, params); - } - } - } - - /** - * return the algorithm name and mode. - * - * @return the name of the underlying algorithm followed by "/CFB" - * and the block size in bits. - */ - public String getAlgorithmName() - { - return cipher.getAlgorithmName() + "/CFB" + (blockSize * 8); - } - - protected byte calculateByte(byte in) - throws DataLengthException, IllegalStateException - { - return (encrypting) ? encryptByte(in) : decryptByte(in); - } - - private byte encryptByte(byte in) - { - if (byteCount == 0) - { - cipher.processBlock(cfbV, 0, cfbOutV, 0); - } - - byte rv = (byte)(cfbOutV[byteCount] ^ in); - inBuf[byteCount++] = rv; - - if (byteCount == blockSize) - { - byteCount = 0; - - System.arraycopy(cfbV, blockSize, cfbV, 0, cfbV.length - blockSize); - System.arraycopy(inBuf, 0, cfbV, cfbV.length - blockSize, blockSize); - } - - return rv; - } - - private byte decryptByte(byte in) - { - if (byteCount == 0) - { - cipher.processBlock(cfbV, 0, cfbOutV, 0); - } - - inBuf[byteCount] = in; - byte rv = (byte)(cfbOutV[byteCount++] ^ in); - - if (byteCount == blockSize) - { - byteCount = 0; - - System.arraycopy(cfbV, blockSize, cfbV, 0, cfbV.length - blockSize); - System.arraycopy(inBuf, 0, cfbV, cfbV.length - blockSize, blockSize); - } - - return rv; - } - - /** - * return the block size we are operating at. - * - * @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; - } - - /** - * Do the appropriate processing for CFB mode encryption. - * - * @param in the array containing the data to be encrypted. - * @param inOff offset into the in array the data starts at. - * @param out the array the encrypted 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 encryptBlock( - byte[] in, - int inOff, - byte[] out, - int outOff) - throws DataLengthException, IllegalStateException - { - processBytes(in, inOff, blockSize, out, outOff); - - return blockSize; - } - - /** - * Do the appropriate processing for CFB mode decryption. - * - * @param in the array containing the data to be decrypted. - * @param inOff offset into the in array the data starts at. - * @param out the array the encrypted 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 decryptBlock( - byte[] in, - int inOff, - byte[] out, - int outOff) - throws DataLengthException, IllegalStateException - { - processBytes(in, inOff, blockSize, out, outOff); - - return blockSize; - } - - /** - * Return the current state of the initialisation vector. - * - * @return current IV - */ - public byte[] getCurrentIV() - { - return Arrays.clone(cfbV); - } - - /** - * reset the chaining vector back to the IV and reset the underlying - * cipher. - */ - public void reset() - { - System.arraycopy(IV, 0, cfbV, 0, IV.length); - Arrays.fill(inBuf, (byte)0); - byteCount = 0; - - cipher.reset(); - } -} |