de.flexiprovider.core.mac
Class HMac

java.lang.Object
  |
  +--javax.crypto.MacSpi
        |
        +--de.flexiprovider.api.Mac
              |
              +--de.flexiprovider.core.mac.HMac

Direct Known Subclasses:

HMac.DHA256, HMac.FORK256, HMac.MD4, HMac.MD5, HMac.RIPEMD128, HMac.RIPEMD160, HMac.RIPEMD256, HMac.RIPEMD320, HMac.SHA1, HMac.SHA224, HMac.SHA256, HMac.SHA384, HMac.SHA512, HMac.Tiger

public class HMac

extends Mac

This class extends the MAC class for providing the functionality of the HMAC(Keyed-Hashing for Message Authentication) algorithm, as specified in RFC 2104.

Any application dealing with MAC computation uses the "getInstance"-method of the MAC class for creating a MAC object.

The FlexiProvider supports HMAC computation based on SHA1, MD5, and RIPEMD160 hash algorithms.

Inner Class Summary

static class	HMac.DHA256
static class	HMac.FORK256
static class	HMac.MD4
static class	HMac.MD5
static class	HMac.RIPEMD128
static class	HMac.RIPEMD160
static class	HMac.RIPEMD256
static class	HMac.RIPEMD320
static class	HMac.SHA1
static class	HMac.SHA224
static class	HMac.SHA256
static class	HMac.SHA384
static class	HMac.SHA512
static class	HMac.Tiger

Constructor Summary

(package private)

HMac(MessageDigest md, int blockSize) Creates a new HMac for the specified hash algorithm.

Method Summary

byte[]	doFinal() Return the computed MAC value.
int	getMacLength() Return the MAC length.
void	init(SecretKey key, AlgorithmParameterSpec params) Initialize this MAC object with the given key and algorithm parameters (not used).
void	reset() Resets this MAC object so that it may be used for further MAC comptations.
void	update(byte input) Process the given byte.
void	update(byte[] input, int inOff, int inLen) Processes the given number of bytes, supplied in a byte array starting at the given position.

Methods inherited from class de.flexiprovider.api.Mac

doFinal, doFinal, engineDoFinal, engineGetMacLength, engineInit, engineReset, engineUpdate, engineUpdate, init, update

Methods inherited from class javax.crypto.MacSpi

clone

Methods inherited from class java.lang.Object

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

Constructor Detail

HMac

HMac(MessageDigest md,
     int blockSize)

Creates a new HMac for the specified hash algorithm. This constructor is called by every subclass for specifying the particular hash algorithm to be used for HMac computation.

Parameters:

md - the hash algorithm to use.

blockSize - TODO

Method Detail

getMacLength

public int getMacLength()

Description copied from class: Mac

Return the MAC length. This method is guaranteed to return a sane value only after the MAC has been initialized.

Overrides:

getMacLength in class Mac

Returns:

the length of the calculated MAC value in bytes

init

public void init(SecretKey key,
                 AlgorithmParameterSpec params)
          throws InvalidKeyException

Initialize this MAC object with the given key and algorithm parameters (not used).

Overrides:

init in class Mac

Parameters:

key - the MAC key

params - the algorithm parameters (not used)

Throws:

InvalidKeyException - if the key is not an instance of HMacKey.

update

public void update(byte[] input,
                   int inOff,
                   int inLen)

Processes the given number of bytes, supplied in a byte array starting at the given position.

Overrides:

update in class Mac

Parameters:

input - the byte array containing the input

inOff - the offset where the input starts

inLen - the length of the input

update

public void update(byte input)

Process the given byte.

Overrides:

update in class Mac

Parameters:

input - the byte to be processed

doFinal

public byte[] doFinal()

Return the computed MAC value. After the MAC has been computed, the MAC object is reset and has to be initialized again for further MAC computations.

Overrides:

doFinal in class Mac

Returns:

the computed MAC value

reset

public void reset()

Resets this MAC object so that it may be used for further MAC comptations.

Overrides:

reset in class Mac