Class AES

java.lang.Object
com.trilead.ssh2.crypto.cipher.AES
All Implemented Interfaces:
BlockCipher
public class AES extends 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 fast version with 8Kbytes of static tables for round precomputation

Version:
$Id: AES.java,v 1.1 2007/10/15 12:49:55 cplattne Exp $

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private static final int
    BLOCK_SIZE
     
    private int
    C0
     
    private int
    C1
     
    private int
    C2
     
    private int
    C3
     
    private boolean
    doEncrypt
     
    private static final int
    m1
     
    private static final int
    m2
     
    private static final int
    m3
     
    private static final int[]
    rcon
     
    private int
    ROUNDS
     
    private static final byte[]
    S
     
    private static final byte[]
    Si
     
    private static final int[]
    T0
     
    private static final int[]
    T1
     
    private static final int[]
    T2
     
    private static final int[]
    T3
     
    private static final int[]
    Tinv0
     
    private static final int[]
    Tinv1
     
    private static final int[]
    Tinv2
     
    private static final int[]
    Tinv3
     
    private int[][]
    WorkingKey
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    AES()
    default constructor - 128 bit block size.

  • Method Summary

    Modifier and Type
    Method
    Description
    private final void
    decryptBlock(int[][] KW)
     
    private final void
    encryptBlock(int[][] KW)
     
    private final int
    FFmulX(int x)
     
    private final 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
    final String
    getAlgorithmName()
     
    final int
    getBlockSize()
     
    final void
    init(boolean forEncryption, byte[] key)
    initialise an AES cipher.
    private final int
    inv_mcol(int x)
     
    private final void
    packBlock(byte[] bytes, int off)
     
    final int
    processBlock(byte[] in, int inOff, byte[] out, int outOff)
     
    final void
    reset()
     
    private final int
    shift(int r, int shift)
     
    private final int
    subWord(int x)
     
    void
    transformBlock(byte[] src, int srcoff, byte[] dst, int dstoff)
     
    private final void
    unpackBlock(byte[] bytes, int off)
     

    Methods inherited from class Object

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

  • Field Details

    • S

      private static final byte[] S

    • Si

      private static final byte[] Si

    • rcon

      private static final int[] rcon

    • T0

      private static final int[] T0

    • T1

      private static final int[] T1

    • T2

      private static final int[] T2

    • T3

      private static final int[] T3

    • Tinv0

      private static final int[] Tinv0

    • Tinv1

      private static final int[] Tinv1

    • Tinv2

      private static final int[] Tinv2

    • Tinv3

      private static final int[] Tinv3

    • m1

      private static final int m1
      See Also:

    • m2

      private static final int m2
      See Also:

    • m3

      private static final int m3
      See Also:

    • ROUNDS

      private int ROUNDS

    • WorkingKey

      private int[][] WorkingKey

    • C0

      private int C0

    • C1

      private int C1

    • C2

      private int C2

    • C3

      private int C3

    • doEncrypt

      private boolean doEncrypt

    • BLOCK_SIZE

      private static final int BLOCK_SIZE
      See Also:

  • Constructor Details

    • AES

      public AES()
      default constructor - 128 bit block size.

  • Method Details

    • shift

      private final int shift(int r, int shift)

    • FFmulX

      private final int FFmulX(int x)

    • inv_mcol

      private final int inv_mcol(int x)

    • subWord

      private final int subWord(int x)

    • generateWorkingKey

      private final 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 final void init(boolean forEncryption, byte[] key)
      initialise an AES cipher.
      Specified by:
      init in interface BlockCipher
      Parameters:
      forEncryption - whether or not we are for encryption.
      key - the key required to set up the cipher.
      Throws:
      IllegalArgumentException - if the params argument is inappropriate.

    • getAlgorithmName

      public final String getAlgorithmName()

    • getBlockSize

      public final int getBlockSize()
      Specified by:
      getBlockSize in interface BlockCipher

    • processBlock

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

    • reset

      public final void reset()

    • 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)

    • transformBlock

      public void transformBlock(byte[] src, int srcoff, byte[] dst, int dstoff)
      Specified by:
      transformBlock in interface BlockCipher