Package it.ipzs.cieid

Class AESFast

java.lang.Object
it.ipzs.cieid.AESFast

public class AESFast extends Object
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

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    class 
     
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private static final int
     
    static final int
     
    private int
     
    private int
     
    private int
     
    private int
     
    private boolean
     
    static final int
     
    static final int
     
    static final int
     
    static final int
     
    static final int
     
    private static final int
     
    private static final int
     
    private static final int
     
    private static final int[]
     
    private int
     
    private static final byte[]
     
    private static final byte[]
     
    private static final int[]
     
    private static final int[]
     
    private static final int[]
     
    private static final int[]
     
    private static final int[]
     
    private static final int[]
     
    private static final int[]
     
    private static final int[]
     
    private int[][]
     
  • Constructor Summary

    Constructors
    Constructor
    Description
    default constructor - 128 bit block size.
  • Method Summary

    Modifier and Type
    Method
    Description
    private final void
    decryptBlock(int[][] KW)
     
    byte[]
    decryptCBC(byte[] ciphertext, int nOffset, byte[] iv)
     
    static byte[]
    decryptCBC(byte[] ciphertext, int nOffset, byte[] key, int keylen, byte[] iv, int nBlockLen)
    Encrypt a palintext.
    byte[]
    decryptECB(byte[] ciphertext, int nOffset)
    Encrypt a palintext.
    static byte[]
    decryptECB(byte[] ciphertext, int nOffset, byte[] key, int keylen, int nBlockLen)
    Decrypt a ciphertext.
    private final 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
     
    int
     
    void
    init(boolean forEncryption, byte[] key)
    initialise an AES cipher.
    private int
    inv_mcol(int x)
     
    static byte[]
    makeSafeKey(byte[] k, int keysize)
     
    private final void
    packBlock(byte[] bytes, int off)
     
    int
    processBlock(byte[] in, int inOff, byte[] out, int outOff)
     
    void
     
    private int
    shift(int r, int shift)
     
    private int
    subWord(int x)
     
    private final void
    unpackBlock(byte[] bytes, int off)
     
    private byte[]
    unpad(byte[] plaintext)
     
    private void
    xor(byte[] block, int offsetblok, byte[] iv, int offsetiv, byte[] xoredblock, int offserxored, int blocklen)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

    • KEY_SIZE_256

      public static final int KEY_SIZE_256
      See Also:
    • KEY_SIZE_224

      public static final int KEY_SIZE_224
      See Also:
    • KEY_SIZE_160

      public static final int KEY_SIZE_160
      See Also:
    • KEY_SIZE_192

      public static final int KEY_SIZE_192
      See Also:
    • KEY_SIZE_128

      public static final int KEY_SIZE_128
      See Also:
    • BLOCK_SIZE_128

      public static final int BLOCK_SIZE_128
      See Also:
    • 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
    • forEncryption

      private boolean forEncryption
    • BLOCK_SIZE

      private static final int BLOCK_SIZE
      See Also:
  • Constructor Details

    • AESFast

      public AESFast()
      default constructor - 128 bit block size.
  • Method Details

    • 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, byte[] key)
      initialise an AES cipher.
      Parameters:
      forEncryption - whether or not we are for encryption.
      params - the parameters required to set up the cipher.
      Throws:
      IllegalArgumentException - if the params argument is inappropriate.
    • getAlgorithmName

      public String getAlgorithmName()
    • getBlockSize

      public int getBlockSize()
    • processBlock

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

      public 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)
    • decryptECB

      public byte[] decryptECB(byte[] ciphertext, int nOffset)
      Encrypt a palintext.
      Parameters:
      ciphertext - The ciphertext.
      nOffset - Index of in from which to start considering data.
      sessionKey - The session key to use for encryption.
      blockSize - The block size in bytes of this Rijndael.
      Returns:
      The plaintext generated from ciphertext using the session key.
    • decryptCBC

      public byte[] decryptCBC(byte[] ciphertext, int nOffset, byte[] iv)
    • unpad

      private byte[] unpad(byte[] plaintext)
    • xor

      private void xor(byte[] block, int offsetblok, byte[] iv, int offsetiv, byte[] xoredblock, int offserxored, int blocklen)
    • decryptECB

      public static byte[] decryptECB(byte[] ciphertext, int nOffset, byte[] key, int keylen, int nBlockLen)
      Decrypt a ciphertext.
      Parameters:
      ciphertext - The ciphertext.
      nOffset - Index of in from which to start considering data.
      key - The session key to use for encryption.
      blockSize - The block size in bytes of this Rijndael.
      Returns:
      The plaintext generated from ciphertext using the session key.
    • decryptCBC

      public static byte[] decryptCBC(byte[] ciphertext, int nOffset, byte[] key, int keylen, byte[] iv, int nBlockLen)
      Encrypt a palintext.
      Parameters:
      ciphertext - The ciphertext.
      nOffset - Index of in from which to start considering data.
      key - The session key to use for encryption.
      blockSize - The block size in bytes of this Rijndael.
      Returns:
      The plaintext generated from ciphertext using the session key.
    • makeSafeKey

      public static byte[] makeSafeKey(byte[] k, int keysize)