org.bouncycastle.crypto.engines

Class AESEngine

java.lang.Object

org.bouncycastle.crypto.DefaultMultiBlockCipher

org.bouncycastle.crypto.engines.AESEngine

All Implemented Interfaces:

BlockCipher, MultiBlockCipher

public class AESEngine
extends DefaultMultiBlockCipher

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

For further details see: https://csrc.nist.gov/encryption/aes/.

This implementation is based on optimizations from Dr. Brian Gladman's paper and C code at https://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.

Constructor Summary

Constructors

Constructor and Description
AESEngine() default constructor - 128 bit block size.

Method Summary

Modifier and Type	Method and Description
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.
static MultiBlockCipher	newInstance() Return an AESEngine - native mode if possible.
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.
java.lang.String	toString()

Methods inherited from class org.bouncycastle.crypto.DefaultMultiBlockCipher

getMultiBlockSize, processBlocks

Methods inherited from class java.lang.Object

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

Constructor Detail

AESEngine

public AESEngine()

default constructor - 128 bit block size.

Method Detail

newInstance

public static MultiBlockCipher newInstance()

Return an AESEngine - native mode if possible.

Returns:

an AES ECB mode cipher.

init

public void init(boolean forEncryption,
                 CipherParameters params)

initialise an AES cipher.

Parameters:

forEncryption - whether 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.

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).

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.

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).

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object