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view tango/tango/io/digest/MerkleDamgard.d @ 341:1bb99290e03a trunk
[svn r362] Started merging the old 'test' dir as well as the newer 'tangotests' dir into 'tests/mini' and 'tests/minicomplex'.
author | lindquist |
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date | Sun, 13 Jul 2008 02:51:19 +0200 |
parents | 1700239cab2e |
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/******************************************************************************* copyright: Copyright (c) 2006 Tango. All rights reserved license: BSD style: see doc/license.txt for details version: Initial release: Feb 2006 author: Regan Heath, Oskar Linde This module implements a generic Merkle-Damgard hash function *******************************************************************************/ module tango.io.digest.MerkleDamgard; public import tango.core.ByteSwap; public import tango.io.digest.Digest; /******************************************************************************* Extending MerkleDamgard to create a custom hash function requires the implementation of a number of abstract methods. These include: --- public uint digestSize(); protected void reset(); protected void createDigest(ubyte[] buf); protected uint blockSize(); protected uint addSize(); protected void padMessage(ubyte[] data); protected void transform(ubyte[] data); --- In addition there exist two further abstract methods; these methods have empty default implementations since in some cases they are not required: --- protected abstract void padLength(ubyte[] data, ulong length); protected abstract void extend(); --- The method padLength() is required to implement the SHA series of Hash functions and also the Tiger algorithm. Method extend() is required only to implement the MD2 digest. The basic sequence of internal events is as follows: $(UL $(LI transform(), 0 or more times) $(LI padMessage()) $(LI padLength()) $(LI transform()) $(LI extend()) $(LI createDigest()) $(LI reset()) ) *******************************************************************************/ package class MerkleDamgard : Digest { private uint bytes; private ubyte[] buffer; /*********************************************************************** Constructs the digest Params: buf = a buffer with enough space to hold the digest Remarks: Constructs the digest. ***********************************************************************/ protected abstract void createDigest(ubyte[] buf); /*********************************************************************** Digest block size Returns: the block size Remarks: Specifies the size (in bytes) of the block of data to pass to each call to transform(). ***********************************************************************/ protected abstract uint blockSize(); /*********************************************************************** Length padding size Returns: the length padding size Remarks: Specifies the size (in bytes) of the padding which uses the length of the data which has been fed to the algorithm, this padding is carried out by the padLength method. ***********************************************************************/ protected abstract uint addSize(); /*********************************************************************** Pads the digest data Params: data = a slice of the digest buffer to fill with padding Remarks: Fills the passed buffer slice with the appropriate padding for the final call to transform(). This padding will fill the message data buffer up to blockSize()-addSize(). ***********************************************************************/ protected abstract void padMessage(ubyte[] data); /*********************************************************************** Performs the length padding Params: data = the slice of the digest buffer to fill with padding length = the length of the data which has been processed Remarks: Fills the passed buffer slice with addSize() bytes of padding based on the length in bytes of the input data which has been processed. ***********************************************************************/ protected void padLength(ubyte[] data, ulong length) {} /*********************************************************************** Performs the digest on a block of data Params: data = the block of data to digest Remarks: The actual digest algorithm is carried out by this method on the passed block of data. This method is called for every blockSize() bytes of input data and once more with the remaining data padded to blockSize(). ***********************************************************************/ protected abstract void transform(ubyte[] data); /*********************************************************************** Final processing of digest. Remarks: This method is called after the final transform just prior to the creation of the final digest. The MD2 algorithm requires an additional step at this stage. Future digests may or may not require this method. ***********************************************************************/ protected void extend() {} /*********************************************************************** Construct a digest Remarks: Constructs the internal buffer for use by the digest, the buffer size (in bytes) is defined by the abstract method blockSize(). ***********************************************************************/ this() { buffer = new ubyte[blockSize()]; reset(); } /*********************************************************************** Initialize the digest Remarks: Returns the digest state to its initial value ***********************************************************************/ protected void reset() { bytes = 0; } /*********************************************************************** Digest additional data Params: input = the data to digest Remarks: Continues the digest operation on the additional data. ***********************************************************************/ void update (void[] input) { auto block = blockSize(); uint i = bytes & (block-1); ubyte[] data = cast(ubyte[]) input; bytes += data.length; if (data.length+i < block) buffer[i..i+data.length] = data[]; else { buffer[i..block] = data[0..block-i]; transform (buffer); for (i=block-i; i+block-1 < data.length; i += block) transform(data[i..i+block]); buffer[0..data.length-i] = data[i..data.length]; } } /*********************************************************************** Complete the digest Returns: the completed digest Remarks: Concludes the algorithm producing the final digest. ***********************************************************************/ ubyte[] binaryDigest (ubyte[] buf = null) { auto block = blockSize(); uint i = bytes & (block-1); if (i < block-addSize) padMessage (buffer[i..block-addSize]); else { padMessage (buffer[i..block]); transform (buffer); buffer[] = 0; } padLength (buffer[block-addSize..block], bytes); transform (buffer); extend (); if (buf.length < digestSize()) buf.length = digestSize(); createDigest (buf); reset (); return buf; } /*********************************************************************** Converts 8 bit to 32 bit Little Endian Params: input = the source array output = the destination array Remarks: Converts an array of ubyte[] into uint[] in Little Endian byte order. ***********************************************************************/ static protected final void littleEndian32(ubyte[] input, uint[] output) { assert(output.length == input.length/4); output[] = cast(uint[]) input; version (BigEndian) ByteSwap.swap32 (output.ptr, output.length * uint.sizeof); } /*********************************************************************** Converts 8 bit to 32 bit Big Endian Params: input = the source array output = the destination array Remarks: Converts an array of ubyte[] into uint[] in Big Endian byte order. ***********************************************************************/ static protected final void bigEndian32(ubyte[] input, uint[] output) { assert(output.length == input.length/4); output[] = cast(uint[]) input; version(LittleEndian) ByteSwap.swap32 (output.ptr, output.length * uint.sizeof); } /*********************************************************************** Converts 8 bit to 64 bit Little Endian Params: input = the source array output = the destination array Remarks: Converts an array of ubyte[] into ulong[] in Little Endian byte order. ***********************************************************************/ static protected final void littleEndian64(ubyte[] input, ulong[] output) { assert(output.length == input.length/8); output[] = cast(ulong[]) input; version (BigEndian) ByteSwap.swap64 (output.ptr, output.length * ulong.sizeof); } /*********************************************************************** Converts 8 bit to 64 bit Big Endian Params: input = the source array output = the destination array Remarks: Converts an array of ubyte[] into ulong[] in Big Endian byte order. ***********************************************************************/ static protected final void bigEndian64(ubyte[] input, ulong[] output) { assert(output.length == input.length/8); output[] = cast(ulong[]) input; version (LittleEndian) ByteSwap.swap64 (output.ptr, output.length * ulong.sizeof); } /*********************************************************************** Rotate left by n Params: x = the value to rotate n = the amount to rotate by Remarks: Rotates a 32 bit value by the specified amount. ***********************************************************************/ static protected final uint rotateLeft(uint x, uint n) { /+version (D_InlineAsm_X86) version (DigitalMars) { asm { naked; mov ECX,EAX; mov EAX,4[ESP]; rol EAX,CL; ret 4; } } else return (x << n) | (x >> (32-n)); else +/ return (x << n) | (x >> (32-n)); } }