org.bouncycastle.crypto.macs
Class CMac
java.lang.Object
org.bouncycastle.crypto.macs.CMac
- Mac
public class CMac
extends java.lang.Object
CMAC - as specified at www.nuee.nagoya-u.ac.jp/labs/tiwata/omac/omac.html
CMAC is analogous to OMAC1 - see also en.wikipedia.org/wiki/CMAC
CMAC is a NIST recomendation - see
csrc.nist.gov/CryptoToolkit/modes/800-38_Series_Publications/SP800-38B.pdf
CMAC/OMAC1 is a blockcipher-based message authentication code designed and
analyzed by Tetsu Iwata and Kaoru Kurosawa.
CMAC/OMAC1 is a simple variant of the CBC MAC (Cipher Block Chaining Message
Authentication Code). OMAC stands for One-Key CBC MAC.
It supports 128- or 64-bits block ciphers, with any key size, and returns
a MAC with dimension less or equal to the block size of the underlying
cipher.
CMac(BlockCipher cipher) - create a standard MAC based on a CBC block cipher (64 or 128 bit block).
|
CMac(BlockCipher cipher, int macSizeInBits) - create a standard MAC based on a block cipher with the size of the
MAC been given in bits.
|
CMac
public CMac(BlockCipher cipher)
create a standard MAC based on a CBC block cipher (64 or 128 bit block).
This will produce an authentication code the length of the block size
of the cipher.
cipher
- the cipher to be used as the basis of the MAC generation.
CMac
public CMac(BlockCipher cipher,
int macSizeInBits)
create a standard MAC based on a block cipher with the size of the
MAC been given in bits.
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).
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 and <= 128.
doFinal
public int doFinal(byte[] out,
int outOff)
- doFinal in interface Mac
reset
public void reset()
Reset the mac generator.
- reset in interface Mac
update
public void update(byte in)
- update in interface Mac
update
public void update(byte[] in,
int inOff,
int len)
- update in interface Mac