io.milton.zsync

Class MD4

java.lang.Object

java.security.MessageDigestSpi

io.milton.zsync.MD4

All Implemented Interfaces:

Cloneable

Direct Known Subclasses:

BrokenMD4

public class MD4
extends MessageDigestSpi
implements Cloneable

An implementation of Ron Rivest's MD4 message digest algorithm. MD4 was the precursor to the stronger MD5 algorithm, and while not considered cryptograpically secure itself, MD4 is in use in various applications. It is slightly faster than MD5.

This implementation is derived from the version of MD4 in GNU Crypto.

References:

1. The MD4 Message- Digest Algorithm.
   R. Rivest.

Version:

$Revision: 1.9 $

Field Summary

Fields

Modifier and Type	Field and Description
protected int	a
protected static int	A
protected int	b
protected static int	B
static int	BLOCK_LENGTH The MD4 algorithm operates on 512-bit blocks, or 64 bytes.
protected byte[]	buffer
protected int	c
protected static int	C
protected long	count
protected int	d
protected static int	D
static int	DIGEST_LENGTH An MD4 message digest is always 128-bits long, or 16 bytes.

Constructor Summary

Constructors

Constructor and Description
MD4() Trivial zero-argument constructor.

Method Summary

Modifier and Type	Method and Description
Object	clone()
protected byte[]	engineDigest() Pack the four chaining variables into a byte array.
protected int	engineDigest(byte[] out, int off, int len)
protected int	engineGetDigestLength()
protected void	engineReset() Reset the four chaining variables.
void	engineUpdate(byte b)
protected void	engineUpdate(byte[] b, int offset, int len)
protected byte[]	padBuffer() Pad the buffer by appending the byte 0x80, then as many zero bytes to fill the buffer 8 bytes shy of being a multiple of 64 bytes, then append the length of the buffer, in bits, before padding.
protected void	transform(byte[] in, int offset) Transform a 64-byte block.

Methods inherited from class java.security.MessageDigestSpi

engineUpdate

Methods inherited from class java.lang.Object

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

Field Detail

DIGEST_LENGTH

public static final int DIGEST_LENGTH

An MD4 message digest is always 128-bits long, or 16 bytes.

See Also:

Constant Field Values

BLOCK_LENGTH

public static final int BLOCK_LENGTH

The MD4 algorithm operates on 512-bit blocks, or 64 bytes.

See Also:

Constant Field Values

A

protected static final int A

See Also:

Constant Field Values

B

protected static final int B

See Also:

Constant Field Values

C

protected static final int C

See Also:

Constant Field Values

D

protected static final int D

See Also:

Constant Field Values

a

protected int a

b

protected int b

c

protected int c

d

protected int d

count

protected long count

buffer

protected final byte[] buffer

Constructor Detail

MD4

public MD4()

Trivial zero-argument constructor.

Method Detail

clone

public Object clone()

Overrides:

clone in class MessageDigestSpi

engineGetDigestLength

protected int engineGetDigestLength()

Overrides:

engineGetDigestLength in class MessageDigestSpi

engineUpdate

public void engineUpdate(byte b)

Specified by:

engineUpdate in class MessageDigestSpi

engineUpdate

protected void engineUpdate(byte[] b,
                            int offset,
                            int len)

Specified by:

engineUpdate in class MessageDigestSpi

engineDigest

protected byte[] engineDigest()

Pack the four chaining variables into a byte array.

Specified by:

engineDigest in class MessageDigestSpi

engineDigest

protected int engineDigest(byte[] out,
                           int off,
                           int len)
                    throws DigestException

Overrides:

engineDigest in class MessageDigestSpi

Throws:

DigestException

engineReset

protected void engineReset()

Reset the four chaining variables.

Specified by:

engineReset in class MessageDigestSpi

padBuffer

protected byte[] padBuffer()

Pad the buffer by appending the byte 0x80, then as many zero bytes to fill the buffer 8 bytes shy of being a multiple of 64 bytes, then append the length of the buffer, in bits, before padding.

transform

protected void transform(byte[] in,
                         int offset)

Transform a 64-byte block.