MD5

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com.ssttr.crypto
Class MD5

java.lang.Object
  com.ssttr.crypto.MessageDigest
      com.ssttr.crypto.MD5

public final class MD5
extends MessageDigest

The MD5 class is used to compute an MD5 message digest over a given buffer of bytes. It is an implementation of the RSA Data Security Inc MD5 algorithim as described in internet RFC 1321.

Version:: 06 Oct 1996, 1.9.1

Field Summary

private byte[] buffer


private long count


private static int S11


private static int S12


private static int S13


private static int S14


private static int S21


private static int S22


private static int S23


private static int S24


private static int S31


private static int S32


private static int S33


private static int S34


private static int S41


private static int S42


private static int S43


private static int S44


private int[] state
          containss the computed message digest

private static int[] transformBuffer


Fields inherited from class com.ssttr.crypto.MessageDigest

digestBits, digestValid, testdata

Constructor Summary

MD5()
          Standard constructor, creates a new MD5 instance, allocates its buffers from the heap.

MD5(byte[] mydigest)
          Alternate constructor, allows you to pass in the buffer where you want the resulting digest stored.

Method Summary

private int F(int x, int y, int z)


private int FF(int a, int b, int c, int d, int x, int s, int ac)


void finish()
          Perform the final computations, any buffered bytes are added to the digest, the count is added to the digest, and the resulting digest is stored.

private int G(int x, int y, int z)


java.lang.String getAlg()
          Return a string that represents the algorithim of this message digest.

private int GG(int a, int b, int c, int d, int x, int s, int ac)


private int H(int x, int y, int z)


private int HH(int a, int b, int c, int d, int x, int s, int ac)


private int I(int x, int y, int z)


private int II(int a, int b, int c, int d, int x, int s, int ac)


void init()
          Initialize the MD5 state information and reset the bit count to 0.

private int rotateLeft(int a, int n)


(package private) void transform(byte[] buf, int offset)
          This is where the functions come together as the generic MD5 transformation operation, it is called by update() which is synchronized (to protect transformBuffer)

void update(byte b)
          update adds the passed type to the input buffer

Methods inherited from class com.ssttr.crypto.MessageDigest

benchmark, computeDigest, computeDigest, getDigest, getDigestBytes, getDigestHex, isEqual, isEqual, toString, update, update, update, update, update, update, update, update, update, update, update, updateASCII

Methods inherited from class java.lang.Object

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

Field Detail

state

private int[] state

containss the computed message digest

count

private long count

buffer

private byte[] buffer

transformBuffer

private static int[] transformBuffer

S11

private static final int S11

See Also:: Constant Field Values

S12

private static final int S12

See Also:: Constant Field Values

S13

private static final int S13

See Also:: Constant Field Values

S14

private static final int S14

See Also:: Constant Field Values

S21

private static final int S21

See Also:: Constant Field Values

S22

private static final int S22

See Also:: Constant Field Values

S23

private static final int S23

See Also:: Constant Field Values

S24

private static final int S24

See Also:: Constant Field Values

S31

private static final int S31

See Also:: Constant Field Values

S32

private static final int S32

See Also:: Constant Field Values

S33

private static final int S33

See Also:: Constant Field Values

S34

private static final int S34

See Also:: Constant Field Values

S41

private static final int S41

See Also:: Constant Field Values

S42

private static final int S42

See Also:: Constant Field Values

S43

private static final int S43

See Also:: Constant Field Values

S44

private static final int S44

See Also:: Constant Field Values

Constructor Detail

MD5

public MD5()

Standard constructor, creates a new MD5 instance, allocates its buffers from the heap.

MD5

public MD5(byte[] mydigest)

Alternate constructor, allows you to pass in the buffer where you want the resulting digest stored.

Method Detail

F

private int F(int x,
              int y,
              int z)

G

private int G(int x,
              int y,
              int z)

H

private int H(int x,
              int y,
              int z)

I

private int I(int x,
              int y,
              int z)

rotateLeft

private int rotateLeft(int a,
                       int n)

FF

private int FF(int a,
               int b,
               int c,
               int d,
               int x,
               int s,
               int ac)

GG

private int GG(int a,
               int b,
               int c,
               int d,
               int x,
               int s,
               int ac)

HH

private int HH(int a,
               int b,
               int c,
               int d,
               int x,
               int s,
               int ac)

II

private int II(int a,
               int b,
               int c,
               int d,
               int x,
               int s,
               int ac)

transform

void transform(byte[] buf,
               int offset)

This is where the functions come together as the generic MD5 transformation operation, it is called by update() which is synchronized (to protect transformBuffer)

init

public void init()

Initialize the MD5 state information and reset the bit count to 0. Given this implementation you are constrained to counting 2^64 bits.

Specified by:: init in class MessageDigest

update

public void update(byte b)

update adds the passed type to the input buffer

Specified by:: update in class MessageDigest

finish

public void finish()

Perform the final computations, any buffered bytes are added to the digest, the count is added to the digest, and the resulting digest is stored. After calling final you will need to call init() again to do another digest.

Specified by:: finish in class MessageDigest

getAlg

public java.lang.String getAlg()

Description copied from class: MessageDigest

Return a string that represents the algorithim of this message digest.

Specified by:: getAlg in class MessageDigest