Class AESFast
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
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Nested Class Summary
Nested Classes -
Field Summary
FieldsModifier and TypeFieldDescriptionprivate 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[][]
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprivate 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 valuesint
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
reset()
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)
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Field Details
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KEY_SIZE_256
public static final int KEY_SIZE_256- See Also:
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KEY_SIZE_224
public static final int KEY_SIZE_224- See Also:
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KEY_SIZE_160
public static final int KEY_SIZE_160- See Also:
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KEY_SIZE_192
public static final int KEY_SIZE_192- See Also:
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KEY_SIZE_128
public static final int KEY_SIZE_128- See Also:
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BLOCK_SIZE_128
public static final int BLOCK_SIZE_128- See Also:
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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:
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m2
private static final int m2- See Also:
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m3
private static final int m3- See Also:
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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:
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Constructor Details
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AESFast
public AESFast()default constructor - 128 bit block size.
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Method Details
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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.
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getAlgorithmName
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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.
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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.
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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.
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makeSafeKey
public static byte[] makeSafeKey(byte[] k, int keysize)
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