org.bouncycastle.crypto.engines
Class AESEngine

java.lang.Object
  org.bouncycastle.crypto.engines.AESEngine

All Implemented Interfaces:

BlockCipher

public class AESEngine
extends java.lang.Object
implements BlockCipher

an implementation of the AES (Rijndael), from FIPS-197.

For further details see: http://csrc.nist.gov/encryption/aes/. This implementation is based on optimizations from Dr. Brian Gladman's paper and C code at http://fp.gladman.plus.com/cryptography_technology/rijndael/ There are three levels of tradeoff of speed vs memory Because java has no preprocessor, they are written as three separate classes from which to choose The fastest uses 8Kbytes of static tables to precompute round calculations, 4 256 word tables for encryption and 4 for decryption. The middle performance version uses only one 256 word table for each, for a total of 2Kbytes, adding 12 rotate operations per round to compute the values contained in the other tables from the contents of the first. The slowest version uses no static tables at all and computes the values in each round.

This file contains the middle performance version with 2Kbytes of static tables for round precomputation.

Field Summary

private static int	BLOCK_SIZE
private int	C0
private int	C1
private int	C2
private int	C3
private boolean	forEncryption
private static int	m1
private static int	m2
private static int	m3
private static int[]	rcon
private int	ROUNDS
private static byte[]	S
private static byte[]	Si
private static int[]	T0
private static int[]	Tinv0
private int[][]	WorkingKey

Constructor Summary

AESEngine()
default constructor - 128 bit block size.

Method Summary

private void	decryptBlock(int[][] KW)
private void	encryptBlock(int[][] KW)
private int	FFmulX(int x)
private int[][]	generateWorkingKey(byte[] key, boolean forEncryption) Calculate the necessary round keys The number of calculations depends on key size and block size AES specified a fixed block size of 128 bits and key sizes 128/192/256 bits This code is written assuming those are the only possible values
java.lang.String	getAlgorithmName() Return the name of the algorithm the cipher implements.
int	getBlockSize() Return the block size for this cipher (in bytes).
void	init(boolean forEncryption, CipherParameters params) initialise an AES cipher.
private int	inv_mcol(int x)
private void	packBlock(byte[] bytes, int off)
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.
void	reset() Reset the cipher.
private int	shift(int r, int shift)
private int	subWord(int x)
private void	unpackBlock(byte[] bytes, int off)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

S

private static final byte[] S

Si

private static final byte[] Si

rcon

private static final int[] rcon

T0

private static final int[] T0

Tinv0

private static final int[] Tinv0

m1

private static final int m1

See Also:

Constant Field Values

m2

private static final int m2

See Also:

Constant Field Values

m3

private static final int m3

See Also:

Constant Field Values

ROUNDS

private int ROUNDS

WorkingKey

private int[][] WorkingKey

C0

private int C0

C1

private int C1

C2

private int C2

C3

private int C3

forEncryption

private boolean forEncryption

BLOCK_SIZE

private static final int BLOCK_SIZE

See Also:

Constant Field Values

Constructor Detail

AESEngine

public AESEngine()

default constructor - 128 bit block size.

Method Detail

shift

private int shift(int r,
                  int shift)

FFmulX

private int FFmulX(int x)

inv_mcol

private int inv_mcol(int x)

subWord

private int subWord(int x)

generateWorkingKey

private int[][] generateWorkingKey(byte[] key,
                                   boolean forEncryption)

Calculate the necessary round keys The number of calculations depends on key size and block size AES specified a fixed block size of 128 bits and key sizes 128/192/256 bits This code is written assuming those are the only possible values

init

public void init(boolean forEncryption,
                 CipherParameters params)

initialise an AES cipher.

Specified by:

init in interface BlockCipher

Parameters:

forEncryption - whether or not we are for encryption.

params - the parameters required to set up the cipher.

Throws:

java.lang.IllegalArgumentException - if the params argument is inappropriate.

getAlgorithmName

public java.lang.String getAlgorithmName()

Description copied from interface: BlockCipher

Return the name of the algorithm the cipher implements.

Specified by:

getAlgorithmName in interface BlockCipher

Returns:

the name of the algorithm the cipher implements.

getBlockSize

public int getBlockSize()

Description copied from interface: BlockCipher

Return the block size for this cipher (in bytes).

Specified by:

getBlockSize in interface BlockCipher

Returns:

the block size for this cipher in bytes.

processBlock

public int processBlock(byte[] in,
                        int inOff,
                        byte[] out,
                        int outOff)

Description copied from interface: BlockCipher

Process one block of input from the array in and write it to the out array.

Specified by:

processBlock in interface BlockCipher

Parameters:

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.

Returns:

the number of bytes processed and produced.

reset

public void reset()

Description copied from interface: BlockCipher

Reset the cipher. After resetting the cipher is in the same state as it was after the last init (if there was one).

Specified by:

reset in interface BlockCipher

unpackBlock

private final void unpackBlock(byte[] bytes,
                               int off)

packBlock

private final void packBlock(byte[] bytes,
                             int off)

encryptBlock

private final void encryptBlock(int[][] KW)

decryptBlock

private final void decryptBlock(int[][] KW)