org.bouncycastle.crypto.macs

Class ISO9797Alg3Mac

public class ISO9797Alg3Mac extends Object implements Mac

DES based CBC Block Cipher MAC according to ISO9797, algorithm 3 (ANSI X9.19 Retail MAC) This could as well be derived from CBCBlockCipherMac, but then the property mac in the base class must be changed to protected
Constructor Summary
ISO9797Alg3Mac(BlockCipher cipher)
create a Retail-MAC based on a CBC block cipher.
ISO9797Alg3Mac(BlockCipher cipher, BlockCipherPadding padding)
create a Retail-MAC based on a CBC block cipher.
ISO9797Alg3Mac(BlockCipher cipher, int macSizeInBits)
create a Retail-MAC based on a block cipher with the size of the MAC been given in bits.
ISO9797Alg3Mac(BlockCipher cipher, int macSizeInBits, BlockCipherPadding padding)
create a standard MAC based on a block cipher with the size of the MAC been given in bits.
Method Summary
intdoFinal(byte[] out, int outOff)
StringgetAlgorithmName()
intgetMacSize()
voidinit(CipherParameters params)
voidreset()
Reset the mac generator.
voidupdate(byte in)
voidupdate(byte[] in, int inOff, int len)

Constructor Detail

ISO9797Alg3Mac

public ISO9797Alg3Mac(BlockCipher cipher)
create a Retail-MAC based on a CBC block cipher. This will produce an authentication code of the length of the block size of the cipher.

Parameters: cipher the cipher to be used as the basis of the MAC generation. This must be DESEngine.

ISO9797Alg3Mac

public ISO9797Alg3Mac(BlockCipher cipher, BlockCipherPadding padding)
create a Retail-MAC based on a CBC block cipher. This will produce an authentication code of the length of the block size of the cipher.

Parameters: cipher the cipher to be used as the basis of the MAC generation. padding the padding to be used to complete the last block.

ISO9797Alg3Mac

public ISO9797Alg3Mac(BlockCipher cipher, int macSizeInBits)
create a Retail-MAC based on a block cipher with the size of the MAC been given in bits. This class uses single DES CBC mode as the basis for the MAC generation.

Note: the size of the MAC must be at least 24 bits (FIPS Publication 81), or 16 bits if being used as a data authenticator (FIPS Publication 113), and in general should be less than the size of the block cipher as it reduces the chance of an exhaustive attack (see Handbook of Applied Cryptography).

Parameters: cipher the cipher to be used as the basis of the MAC generation. macSizeInBits the size of the MAC in bits, must be a multiple of 8.

ISO9797Alg3Mac

public ISO9797Alg3Mac(BlockCipher cipher, int macSizeInBits, BlockCipherPadding padding)
create a standard MAC based on a block cipher with the size of the MAC been given in bits. This class uses single DES CBC mode as the basis for the MAC generation. The final block is decrypted and then encrypted using the middle and right part of the key.

Note: the size of the MAC must be at least 24 bits (FIPS Publication 81), or 16 bits if being used as a data authenticator (FIPS Publication 113), and in general should be less than the size of the block cipher as it reduces the chance of an exhaustive attack (see Handbook of Applied Cryptography).

Parameters: cipher the cipher to be used as the basis of the MAC generation. macSizeInBits the size of the MAC in bits, must be a multiple of 8. padding the padding to be used to complete the last block.

Method Detail

doFinal

public int doFinal(byte[] out, int outOff)

getAlgorithmName

public String getAlgorithmName()

getMacSize

public int getMacSize()

init

public void init(CipherParameters params)

reset

public void reset()
Reset the mac generator.

update

public void update(byte in)

update

public void update(byte[] in, int inOff, int len)