org.bouncycastle.crypto.digests
Class SHA1InterleaveDigest

java.lang.Object
  org.bouncycastle.crypto.digests.SHA1InterleaveDigest

All Implemented Interfaces:

Digest, Memoable

public class SHA1InterleaveDigest

extends java.lang.Object

implements Digest, Memoable

Implementation of the SHA_Interleave function from RFC 2945, section 3.1, as used by SRP-SHA1 to produce a session key twice the length of a regular SHA-1 hash.

The complete input is buffered until doFinal(byte[], int) is called: leading zero bytes are removed, a further leading byte is removed if the remaining length is odd, the even-numbered and odd-numbered bytes are then hashed separately with SHA-1, and the two hashes are interleaved to form the 40 byte result.

Constructor Summary

SHA1InterleaveDigest()

SHA1InterleaveDigest(SHA1InterleaveDigest t)
Copy constructor.

Method Summary

Memoable	copy() Produce a copy of this object with its configuration and in its current state.
int	doFinal(byte[] out, int outOff) close the digest, producing the final digest value.
java.lang.String	getAlgorithmName() return the algorithm name
int	getDigestSize() return the size, in bytes, of the digest produced by this message digest.
void	reset() reset the digest back to it's initial state.
void	reset(Memoable other) Restore a copied object state into this object.
void	update(byte in) update the message digest with a single byte.
void	update(byte[] in, int inOff, int len) update the message digest with a block of bytes.

Methods inherited from class java.lang.Object

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

Constructor Detail

SHA1InterleaveDigest

public SHA1InterleaveDigest()

SHA1InterleaveDigest

public SHA1InterleaveDigest(SHA1InterleaveDigest t)

Copy constructor. This will copy the state of the provided message digest.

Method Detail

getAlgorithmName

public java.lang.String getAlgorithmName()

Description copied from interface: Digest

return the algorithm name

Specified by:

getAlgorithmName in interface Digest

Returns:

the algorithm name

getDigestSize

public int getDigestSize()

Description copied from interface: Digest

return the size, in bytes, of the digest produced by this message digest.

Specified by:

getDigestSize in interface Digest

Returns:

the size, in bytes, of the digest produced by this message digest.

update

public void update(byte in)

Description copied from interface: Digest

update the message digest with a single byte.

Specified by:

update in interface Digest

Parameters:

in - the input byte to be entered.

update

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

Description copied from interface: Digest

update the message digest with a block of bytes.

Specified by:

update in interface Digest

Parameters:

in - the byte array containing the data.

inOff - the offset into the byte array where the data starts.

len - the length of the data.

doFinal

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

Description copied from interface: Digest

close the digest, producing the final digest value. The doFinal call leaves the digest reset.

Specified by:

doFinal in interface Digest

Parameters:

out - the array the digest is to be copied into.

outOff - the offset into the out array the digest is to start at.

reset

public void reset()

Description copied from interface: Digest

reset the digest back to it's initial state.

Specified by:

reset in interface Digest

copy

public Memoable copy()

Description copied from interface: Memoable

Produce a copy of this object with its configuration and in its current state.

The returned object may be used simply to store the state, or may be used as a similar object starting from the copied state.

Specified by:

copy in interface Memoable

reset

public void reset(Memoable other)

Description copied from interface: Memoable

Restore a copied object state into this object.

Implementations of this method should try to avoid or minimise memory allocation to perform the reset.

Specified by:

reset in interface Memoable

Parameters:

other - an object originally copied from an object of the same type as this instance.