org.bouncycastle.crypto.macs
Class HMac

java.lang.Object
  org.bouncycastle.crypto.macs.HMac

All Implemented Interfaces:

Mac

public class HMac
extends java.lang.Object
implements Mac

HMAC implementation based on RFC2104 H(K XOR opad, H(K XOR ipad, text))

Field Summary

private int	blockLength
private static java.util.Hashtable	blockLengths
private Digest	digest
private int	digestSize
private byte[]	inputPad
private static byte	IPAD
private static byte	OPAD
private byte[]	outputPad

Constructor Summary

	HMac(Digest digest) Base constructor for one of the standard digest algorithms that the byteLength of the algorithm is know for.
private	HMac(Digest digest, int byteLength)

Method Summary

int	doFinal(byte[] out, int outOff) Compute the final statge of the MAC writing the output to the out parameter.
java.lang.String	getAlgorithmName() Return the name of the algorithm the MAC implements.
private static int	getByteLength(Digest digest)
int	getMacSize() Return the block size for this MAC (in bytes).
Digest	getUnderlyingDigest()
void	init(CipherParameters params) Initialise the MAC.
void	reset() Reset the mac generator.
void	update(byte in) add a single byte to the mac for processing.
void	update(byte[] in, int inOff, int len)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

IPAD

private static final byte IPAD

See Also:

Constant Field Values

OPAD

private static final byte OPAD

See Also:

Constant Field Values

digest

private Digest digest

digestSize

private int digestSize

blockLength

private int blockLength

inputPad

private byte[] inputPad

outputPad

private byte[] outputPad

blockLengths

private static java.util.Hashtable blockLengths

Constructor Detail

HMac

public HMac(Digest digest)

Base constructor for one of the standard digest algorithms that the byteLength of the algorithm is know for.

Parameters:

digest - the digest.

HMac

private HMac(Digest digest,
             int byteLength)

Method Detail

getByteLength

private static int getByteLength(Digest digest)

getAlgorithmName

public java.lang.String getAlgorithmName()

Description copied from interface: Mac

Return the name of the algorithm the MAC implements.

Specified by:

getAlgorithmName in interface Mac

Returns:

the name of the algorithm the MAC implements.

getUnderlyingDigest

public Digest getUnderlyingDigest()

init

public void init(CipherParameters params)

Description copied from interface: Mac

Initialise the MAC.

Specified by:

init in interface Mac

Parameters:

params - the key and other data required by the MAC.

getMacSize

public int getMacSize()

Description copied from interface: Mac

Return the block size for this MAC (in bytes).

Specified by:

getMacSize in interface Mac

Returns:

the block size for this MAC in bytes.

update

public void update(byte in)

Description copied from interface: Mac

add a single byte to the mac for processing.

Specified by:

update in interface Mac

Parameters:

in - the byte to be processed.

update

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

Specified by:

update in interface Mac

Parameters:

in - the array containing the input.

inOff - the index in the array the data begins at.

len - the length of the input starting at inOff.

doFinal

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

Description copied from interface: Mac

Compute the final statge of the MAC writing the output to the out parameter.

doFinal leaves the MAC in the same state it was after the last init.

Specified by:

doFinal in interface Mac

Parameters:

out - the array the MAC is to be output to.

outOff - the offset into the out buffer the output is to start at.

reset

public void reset()

Reset the mac generator.

Specified by:

reset in interface Mac