diff options
Diffstat (limited to 'core/src/main/java/org/bouncycastle/crypto/modes/OpenPGPCFBBlockCipher.java')
| -rw-r--r-- | core/src/main/java/org/bouncycastle/crypto/modes/OpenPGPCFBBlockCipher.java | 312 |
1 files changed, 0 insertions, 312 deletions
diff --git a/core/src/main/java/org/bouncycastle/crypto/modes/OpenPGPCFBBlockCipher.java b/core/src/main/java/org/bouncycastle/crypto/modes/OpenPGPCFBBlockCipher.java deleted file mode 100644 index e48731b3..00000000 --- a/core/src/main/java/org/bouncycastle/crypto/modes/OpenPGPCFBBlockCipher.java +++ /dev/null @@ -1,312 +0,0 @@ -package org.bouncycastle.crypto.modes; - -import org.bouncycastle.crypto.BlockCipher; -import org.bouncycastle.crypto.CipherParameters; -import org.bouncycastle.crypto.DataLengthException; - -/** - * Implements OpenPGP's rather strange version of Cipher-FeedBack (CFB) mode - * on top of a simple cipher. This class assumes the IV has been prepended - * to the data stream already, and just accomodates the reset after - * (blockSize + 2) bytes have been read. - * <p> - * For further info see <a href="http://www.ietf.org/rfc/rfc2440.html">RFC 2440</a>. - */ -public class OpenPGPCFBBlockCipher - implements BlockCipher -{ - private byte[] IV; - private byte[] FR; - private byte[] FRE; - - private BlockCipher cipher; - - private int count; - private int blockSize; - private boolean forEncryption; - - /** - * Basic constructor. - * - * @param cipher the block cipher to be used as the basis of the - * feedback mode. - */ - public OpenPGPCFBBlockCipher( - BlockCipher cipher) - { - this.cipher = cipher; - - this.blockSize = cipher.getBlockSize(); - this.IV = new byte[blockSize]; - this.FR = new byte[blockSize]; - this.FRE = new byte[blockSize]; - } - - /** - * return the underlying block cipher that we are wrapping. - * - * @return the underlying block cipher that we are wrapping. - */ - public BlockCipher getUnderlyingCipher() - { - return cipher; - } - - /** - * return the algorithm name and mode. - * - * @return the name of the underlying algorithm followed by "/PGPCFB" - * and the block size in bits. - */ - public String getAlgorithmName() - { - return cipher.getAlgorithmName() + "/OpenPGPCFB"; - } - - /** - * return the block size we are operating at. - * - * @return the block size we are operating at (in bytes). - */ - public int getBlockSize() - { - return cipher.getBlockSize(); - } - - /** - * 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 - { - return (forEncryption) ? encryptBlock(in, inOff, out, outOff) : decryptBlock(in, inOff, out, outOff); - } - - /** - * reset the chaining vector back to the IV and reset the underlying - * cipher. - */ - public void reset() - { - count = 0; - - System.arraycopy(IV, 0, FR, 0, FR.length); - - cipher.reset(); - } - - /** - * 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 forEncryption 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 forEncryption, - CipherParameters params) - throws IllegalArgumentException - { - this.forEncryption = forEncryption; - - reset(); - - cipher.init(true, params); - } - - /** - * Encrypt one byte of data according to CFB mode. - * @param data the byte to encrypt - * @param blockOff offset in the current block - * @return the encrypted byte - */ - private byte encryptByte(byte data, int blockOff) - { - return (byte)(FRE[blockOff] ^ data); - } - - /** - * Do the appropriate processing for CFB IV 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. - */ - private int encryptBlock( - byte[] in, - int inOff, - byte[] out, - int outOff) - throws DataLengthException, IllegalStateException - { - if ((inOff + blockSize) > in.length) - { - throw new DataLengthException("input buffer too short"); - } - - if ((outOff + blockSize) > out.length) - { - throw new DataLengthException("output buffer too short"); - } - - if (count > blockSize) - { - FR[blockSize - 2] = out[outOff] = encryptByte(in[inOff], blockSize - 2); - FR[blockSize - 1] = out[outOff + 1] = encryptByte(in[inOff + 1], blockSize - 1); - - cipher.processBlock(FR, 0, FRE, 0); - - for (int n = 2; n < blockSize; n++) - { - FR[n - 2] = out[outOff + n] = encryptByte(in[inOff + n], n - 2); - } - } - else if (count == 0) - { - cipher.processBlock(FR, 0, FRE, 0); - - for (int n = 0; n < blockSize; n++) - { - FR[n] = out[outOff + n] = encryptByte(in[inOff + n], n); - } - - count += blockSize; - } - else if (count == blockSize) - { - cipher.processBlock(FR, 0, FRE, 0); - - out[outOff] = encryptByte(in[inOff], 0); - out[outOff + 1] = encryptByte(in[inOff + 1], 1); - - // - // do reset - // - System.arraycopy(FR, 2, FR, 0, blockSize - 2); - System.arraycopy(out, outOff, FR, blockSize - 2, 2); - - cipher.processBlock(FR, 0, FRE, 0); - - for (int n = 2; n < blockSize; n++) - { - FR[n - 2] = out[outOff + n] = encryptByte(in[inOff + n], n - 2); - } - - count += blockSize; - } - - return blockSize; - } - - /** - * Do the appropriate processing for CFB IV 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. - */ - private int decryptBlock( - byte[] in, - int inOff, - byte[] out, - int outOff) - throws DataLengthException, IllegalStateException - { - if ((inOff + blockSize) > in.length) - { - throw new DataLengthException("input buffer too short"); - } - - if ((outOff + blockSize) > out.length) - { - throw new DataLengthException("output buffer too short"); - } - - if (count > blockSize) - { - byte inVal = in[inOff]; - FR[blockSize - 2] = inVal; - out[outOff] = encryptByte(inVal, blockSize - 2); - - inVal = in[inOff + 1]; - FR[blockSize - 1] = inVal; - out[outOff + 1] = encryptByte(inVal, blockSize - 1); - - cipher.processBlock(FR, 0, FRE, 0); - - for (int n = 2; n < blockSize; n++) - { - inVal = in[inOff + n]; - FR[n - 2] = inVal; - out[outOff + n] = encryptByte(inVal, n - 2); - } - } - else if (count == 0) - { - cipher.processBlock(FR, 0, FRE, 0); - - for (int n = 0; n < blockSize; n++) - { - FR[n] = in[inOff + n]; - out[n] = encryptByte(in[inOff + n], n); - } - - count += blockSize; - } - else if (count == blockSize) - { - cipher.processBlock(FR, 0, FRE, 0); - - byte inVal1 = in[inOff]; - byte inVal2 = in[inOff + 1]; - out[outOff ] = encryptByte(inVal1, 0); - out[outOff + 1] = encryptByte(inVal2, 1); - - System.arraycopy(FR, 2, FR, 0, blockSize - 2); - - FR[blockSize - 2] = inVal1; - FR[blockSize - 1] = inVal2; - - cipher.processBlock(FR, 0, FRE, 0); - - for (int n = 2; n < blockSize; n++) - { - byte inVal = in[inOff + n]; - FR[n - 2] = inVal; - out[outOff + n] = encryptByte(inVal, n - 2); - } - - count += blockSize; - } - - return blockSize; - } -} |