A class that provides CAST key encryption operations,
such as encoding data and generating keys.
All the algorithms herein are from the Internet RFC's
RFC2144 - CAST5 (64bit block, 40-128bit key)
RFC2612 - CAST6 (128bit block, 128-256bit key)
and implement a simplified cryptography interface.
BLOCK_SIZE
protected static final int BLOCK_SIZE
- 8
M32
protected static final int M32
- -1
MAX_ROUNDS
protected static final int MAX_ROUNDS
- 16
RED_ROUNDS
protected static final int RED_ROUNDS
- 12
S1
protected static final int[] S1
S2
protected static final int[] S2
S3
protected static final int[] S3
S4
protected static final int[] S4
S5
protected static final int[] S5
S6
protected static final int[] S6
S7
protected static final int[] S7
S8
protected static final int[] S8
Bits32ToBytes
protected final void Bits32ToBytes(int in,
byte[] b,
int offset)
Bits32ToInts
protected final void Bits32ToInts(int in,
int[] b,
int offset)
BytesTo32bits
protected final int BytesTo32bits(byte[] b,
int i)
CAST_Decipher
protected final void CAST_Decipher(int L16,
int R16,
result[] )
CAST_Encipher
protected final void CAST_Encipher(int L0,
int R0,
result[] )
Does the 16 rounds to encrypt the block.
L0
- the LH-32bits of the plaintext blockR0
- the RH-32bits of the plaintext block
F1
protected final int F1(int D,
int Kmi,
int Kri)
The first of the three processing functions for the
encryption and decryption.
D
- the input to be processedKmi
- the mask to be used from Km[n]Kri
- the rotation value to be used
F2
protected final int F2(int D,
int Kmi,
int Kri)
The second of the three processing functions for the
encryption and decryption.
D
- the input to be processedKmi
- the mask to be used from Km[n]Kri
- the rotation value to be used
F3
protected final int F3(int D,
int Kmi,
int Kri)
The third of the three processing functions for the
encryption and decryption.
D
- the input to be processedKmi
- the mask to be used from Km[n]Kri
- the rotation value to be used
IntsTo32bits
protected final int IntsTo32bits(int[] b,
int i)
decryptBlock
protected int decryptBlock(byte[] src,
int srcIndex,
byte[] dst,
int dstIndex)
Decrypt the given input starting at the given offset and place
the result in the provided buffer starting at the given offset.
src
- The plaintext buffersrcIndex
- An offset into srcdst
- The ciphertext bufferdstIndex
- An offset into dst
encryptBlock
protected int encryptBlock(byte[] src,
int srcIndex,
byte[] dst,
int dstIndex)
Encrypt the given input starting at the given offset and place
the result in the provided buffer starting at the given offset.
src
- The plaintext buffersrcIndex
- An offset into srcdst
- The ciphertext bufferdstIndex
- An offset into dst
getAlgorithmName
public String getAlgorithmName()
Return the name of the algorithm the cipher implements.
- getAlgorithmName in interface BlockCipher
- the name of the algorithm the cipher implements.
getBlockSize
public int getBlockSize()
Return the block size for this cipher (in bytes).
- getBlockSize in interface BlockCipher
- the block size for this cipher in bytes.
init
public void init(boolean encrypting,
CipherParameters params)
initialise a CAST cipher.
- init in interface BlockCipher
encrypting
- whether or not we are for encryption.params
- the parameters required to set up the cipher.
processBlock
public int processBlock(byte[] in,
int inOff,
byte[] out,
int outOff)
Process one block of input from the array in and write it to
the out array.
- processBlock in interface BlockCipher
in
- the array containing the input data.inOff
- offset into the in array the data starts at.out
- the array the output data will be copied into.outOff
- the offset into the out array the output will start at.
- the number of bytes processed and produced.
reset
public void reset()
Reset the cipher. After resetting the cipher is in the same state
as it was after the last init (if there was one).
- reset in interface BlockCipher
setKey
protected void setKey(byte[] key)