Class AESFastEngine

  • All Implemented Interfaces:
    BlockCipher

    public class AESFastEngine
    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 fast version with 8Kbytes of static tables for round precomputation

    • Field Summary

      Fields 
      Modifier and Type Field Description
      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[] T1  
      private static int[] T2  
      private static int[] T3  
      private static int[] Tinv0  
      private static int[] Tinv1  
      private static int[] Tinv2  
      private static int[] Tinv3  
      private int[][] WorkingKey  
    • Constructor Summary

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

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      private void decryptBlock​(int[][] KW)  
      private void encryptBlock​(int[][] KW)  
      private static 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 static 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 static int shift​(int r, int shift)  
      private static 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
      • 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
      • 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
    • Constructor Detail

      • AESFastEngine

        public AESFastEngine()
        default constructor - 128 bit block size.
    • Method Detail

      • shift

        private static int shift​(int r,
                                 int shift)
      • FFmulX

        private static int FFmulX​(int x)
      • inv_mcol

        private static int inv_mcol​(int x)
      • subWord

        private static 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 void unpackBlock​(byte[] bytes,
                                 int off)
      • packBlock

        private void packBlock​(byte[] bytes,
                               int off)
      • encryptBlock

        private void encryptBlock​(int[][] KW)
      • decryptBlock

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