1215870ddd
git-svn-id: svn://10.65.10.50/branches/R_10_00@22976 c028cbd2-c16b-5b4b-a496-9718f37d4682
335 lines
16 KiB
C++
335 lines
16 KiB
C++
/*****************************************************************************************
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*** MD5Checksum.h: interface for the MD5Checksum class.
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*** Developed by Langfine Ltd.
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*** Released to the public domain 12/Nov/2001.
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*** Please visit our website www.langfine.com
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*** Any modifications must be clearly commented to distinguish them from Langfine's
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*** original source code. Please advise Langfine of useful modifications so that we
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*** can make them generally available.
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*****************************************************************************************/
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#ifndef __MD5CHECKSUM_H__
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#define __MD5CHECKSUM_H__
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/****************************************************************************************
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This software is derived from the RSA Data Security, Inc. MD5 Message-Digest Algorithm.
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Incorporation of this statement is a condition of use; please see the RSA
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Data Security Inc copyright notice below:-
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Copyright (C) 1990-2, RSA Data Security, Inc. Created 1990. All
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rights reserved.
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RSA Data Security, Inc. makes no representations concerning either
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the merchantability of this software or the suitability of this
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software for any particular purpose. It is provided "as is"
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without express or implied warranty of any kind.
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These notices must be retained in any copies of any part of this
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documentation and/or software.
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Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
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rights reserved.
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License to copy and use this software is granted provided that it
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is identified as the "RSA Data Security, Inc. MD5 Message-Digest
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Algorithm" in all material mentioning or referencing this software
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or this function.
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License is also granted to make and use derivative works provided
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that such works are identified as "derived from the RSA Data
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Security, Inc. MD5 Message-Digest Algorithm" in all material
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mentioning or referencing the derived work.
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RSA Data Security, Inc. makes no representations concerning either
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the merchantability of this software or the suitability of this
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software for any particular purpose. It is provided "as is"
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without express or implied warranty of any kind.
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These notices must be retained in any copies of any part of this
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documentation and/or software.
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*****************************************************************************************/
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/****************************************************************************************
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This implementation of the RSA MD5 Algorithm was written by Langfine Ltd.
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Langfine Ltd makes no representations concerning either
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the merchantability of this software or the suitability of this
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software for any particular purpose. It is provided "as is"
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without express or implied warranty of any kind.
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In addition to the above, Langfine make no warrant or assurances regarding the
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accuracy of this implementation of the MD5 checksum algorithm nor any assurances regarding
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its suitability for any purposes.
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This implementation may be used freely provided that Langfine is credited
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in a copyright or similar notices (eg, RSA MD5 Algorithm implemented by Langfine
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Ltd.) and provided that the RSA Data Security notices are complied with.
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Langfine may be contacted at mail@langfine.com
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*/
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/*****************************************************************************************
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CLASS: wxMD5Checksum
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DESCRIPTION: Implements the "RSA Data Security, Inc. MD5 Message-Digest Algorithm".
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NOTES: Calculates the RSA MD5 checksum for a file or congiguous array of data.
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Below are extracts from a memo on The MD5 Message-Digest Algorithm by R. Rivest of MIT
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Laboratory for Computer Science and RSA Data Security, Inc., April 1992.
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1. Executive Summary
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This document describes the MD5 message-digest algorithm. The
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algorithm takes as input a message of arbitrary length and produces
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as output a 128-bit "fingerprint" or "message digest" of the input.
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It is conjectured that it is computationally infeasible to produce
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two messages having the same message digest, or to produce any
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message having a given prespecified target message digest. The MD5
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algorithm is intended for digital signature applications, where a
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large file must be "compressed" in a secure manner before being
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encrypted with a private (secret) key under a public-key cryptosystem
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such as RSA.
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The MD5 algorithm is designed to be quite fast on 32-bit machines. In
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addition, the MD5 algorithm does not require any large substitution
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tables; the algorithm can be coded quite compactly.
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The MD5 algorithm is an extension of the MD4 message-digest algorithm
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1,2]. MD5 is slightly slower than MD4, but is more "conservative" in
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design. MD5 was designed because it was felt that MD4 was perhaps
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being adopted for use more quickly than justified by the existing
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critical review; because MD4 was designed to be exceptionally fast,
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it is "at the edge" in terms of risking successful cryptanalytic
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attack. MD5 backs off a bit, giving up a little in speed for a much
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greater likelihood of ultimate security. It incorporates some
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suggestions made by various reviewers, and contains additional
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optimizations. The MD5 algorithm is being placed in the public domain
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for review and possible adoption as a standard.
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2. Terminology and Notation
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In this document a "word" is a 32-bit quantity and a "byte" is an
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eight-bit quantity. A sequence of bits can be interpreted in a
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natural manner as a sequence of bytes, where each consecutive group
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of eight bits is interpreted as a byte with the high-order (most
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significant) bit of each byte listed first. Similarly, a sequence of
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bytes can be interpreted as a sequence of 32-bit words, where each
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consecutive group of four bytes is interpreted as a word with the
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low-order (least significant) byte given first.
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Let x_i denote "x sub i". If the subscript is an expression, we
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surround it in braces, as in x_{i+1}. Similarly, we use ^ for
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superscripts (exponentiation), so that x^i denotes x to the i-th power.
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Let the symbol "+" denote addition of words (i.e., modulo-2^32
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addition). Let X <<< s denote the 32-bit value obtained by circularly
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shifting (rotating) X left by s bit positions. Let not(X) denote the
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bit-wise complement of X, and let X v Y denote the bit-wise OR of X
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and Y. Let X xor Y denote the bit-wise XOR of X and Y, and let XY
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denote the bit-wise AND of X and Y.
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3. MD5 Algorithm Description
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We begin by supposing that we have a b-bit message as input, and that
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we wish to find its message digest. Here b is an arbitrary
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nonnegative integer; b may be zero, it need not be a multiple of
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eight, and it may be arbitrarily large. We imagine the bits of the
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message written down as follows: m_0 m_1 ... m_{b-1}
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The following five steps are performed to compute the message digest
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of the message.
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3.1 Step 1. Append Padding Bits
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The message is "padded" (extended) so that its length (in bits) is
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congruent to 448, modulo 512. That is, the message is extended so
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that it is just 64 bits shy of being a multiple of 512 bits long.
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Padding is always performed, even if the length of the message is
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already congruent to 448, modulo 512.
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Padding is performed as follows: a single "1" bit is appended to the
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message, and then "0" bits are appended so that the length in bits of
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the padded message becomes congruent to 448, modulo 512. In all, at
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least one bit and at most 512 bits are appended.
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3.2 Step 2. Append Length
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A 64-bit representation of b (the length of the message before the
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padding bits were added) is appended to the result of the previous
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step. In the unlikely event that b is greater than 2^64, then only
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the low-order 64 bits of b are used. (These bits are appended as two
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32-bit words and appended low-order word first in accordance with the
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previous conventions.)
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At this point the resulting message (after padding with bits and with
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b) has a length that is an exact multiple of 512 bits. Equivalently,
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this message has a length that is an exact multiple of 16 (32-bit)
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words. Let M[0 ... N-1] denote the words of the resulting message,
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where N is a multiple of 16.
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3.3 Step 3. Initialize MD Buffer
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A four-word buffer (A,B,C,D) is used to compute the message digest.
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Here each of A, B, C, D is a 32-bit register. These registers are
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initialized to the following values in hexadecimal, low-order bytes first):
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word A: 01 23 45 67 word B: 89 ab cd ef
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word C: fe dc ba 98 word D: 76 54 32 10
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3.4 Step 4. Process Message in 16-Word Blocks
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We first define four auxiliary functions that each take as input
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three 32-bit words and produce as output one 32-bit word.
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F(X,Y,Z) = XY v not(X) Z G(X,Y,Z) = XZ v Y not(Z)
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H(X,Y,Z) = X xor Y xor Z I(X,Y,Z) = Y xor (X v not(Z))
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In each bit position F acts as a conditional: if X then Y else Z.
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The function F could have been defined using + instead of v since XY
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and not(X)Z will never have 1's in the same bit position.) It is
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interesting to note that if the bits of X, Y, and Z are independent
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and unbiased, the each bit of F(X,Y,Z) will be independent and unbiased.
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The functions G, H, and I are similar to the function F, in that they
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act in "bitwise parallel" to produce their output from the bits of X,
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Y, and Z, in such a manner that if the corresponding bits of X, Y,
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and Z are independent and unbiased, then each bit of G(X,Y,Z),
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H(X,Y,Z), and I(X,Y,Z) will be independent and unbiased. Note that
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the function H is the bit-wise "xor" or "parity" function of its inputs.
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This step uses a 64-element table T[1 ... 64] constructed from the
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sine function. Let T[i] denote the i-th element of the table, which
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is equal to the integer part of 4294967296 times abs(sin(i)), where i
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is in radians. The elements of the table are given in the appendix.
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Do the following:
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//Process each 16-word block.
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For i = 0 to N/16-1 do // Copy block i into X.
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For j = 0 to 15 do
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Set X[j] to M[i*16+j].
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end //of loop on j
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// Save A as AA, B as BB, C as CC, and D as DD.
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AA = A BB = B
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CC = C DD = D
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// Round 1.
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// Let [abcd k s i] denote the operation
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// a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s).
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// Do the following 16 operations.
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[ABCD 0 7 1] [DABC 1 12 2] [CDAB 2 17 3] [BCDA 3 22 4]
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[ABCD 4 7 5] [DABC 5 12 6] [CDAB 6 17 7] [BCDA 7 22 8]
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[ABCD 8 7 9] [DABC 9 12 10] [CDAB 10 17 11] [BCDA 11 22 12]
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[ABCD 12 7 13] [DABC 13 12 14] [CDAB 14 17 15] [BCDA 15 22 16]
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// Round 2.
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// Let [abcd k s i] denote the operation
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// a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s).
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// Do the following 16 operations.
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[ABCD 1 5 17] [DABC 6 9 18] [CDAB 11 14 19] [BCDA 0 20 20]
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[ABCD 5 5 21] [DABC 10 9 22] [CDAB 15 14 23] [BCDA 4 20 24]
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[ABCD 9 5 25] [DABC 14 9 26] [CDAB 3 14 27] [BCDA 8 20 28]
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[ABCD 13 5 29] [DABC 2 9 30] [CDAB 7 14 31] [BCDA 12 20 32]
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// Round 3.
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// Let [abcd k s t] denote the operation
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// a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s).
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// Do the following 16 operations.
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[ABCD 5 4 33] [DABC 8 11 34] [CDAB 11 16 35] [BCDA 14 23 36]
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[ABCD 1 4 37] [DABC 4 11 38] [CDAB 7 16 39] [BCDA 10 23 40]
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[ABCD 13 4 41] [DABC 0 11 42] [CDAB 3 16 43] [BCDA 6 23 44]
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[ABCD 9 4 45] [DABC 12 11 46] [CDAB 15 16 47] [BCDA 2 23 48]
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// Round 4.
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// Let [abcd k s t] denote the operation
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// a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s).
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// Do the following 16 operations.
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[ABCD 0 6 49] [DABC 7 10 50] [CDAB 14 15 51] [BCDA 5 21 52]
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[ABCD 12 6 53] [DABC 3 10 54] [CDAB 10 15 55] [BCDA 1 21 56]
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[ABCD 8 6 57] [DABC 15 10 58] [CDAB 6 15 59] [BCDA 13 21 60]
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[ABCD 4 6 61] [DABC 11 10 62] [CDAB 2 15 63] [BCDA 9 21 64]
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// Then perform the following additions. (That is increment each
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// of the four registers by the value it had before this block
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// was started.)
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A = A + AA B = B + BB C = C + CC D = D + DD
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end // of loop on i
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3.5 Step 5. Output
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The message digest produced as output is A, B, C, D. That is, we
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begin with the low-order byte of A, and end with the high-order byte of D.
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This completes the description of MD5.
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Summary
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The MD5 message-digest algorithm is simple to implement, and provides
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a "fingerprint" or message digest of a message of arbitrary length.
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It is conjectured that the difficulty of coming up with two messages
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having the same message digest is on the order of 2^64 operations,
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and that the difficulty of coming up with any message having a given
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message digest is on the order of 2^128 operations. The MD5 algorithm
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has been carefully scrutinized for weaknesses. It is, however, a
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relatively new algorithm and further security analysis is of course
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justified, as is the case with any new proposal of this sort.
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5. Differences Between MD4 and MD5
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The following are the differences between MD4 and MD5:
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1. A fourth round has been added.
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2. Each step now has a unique additive constant.
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3. The function g in round 2 was changed from (XY v XZ v YZ) to
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(XZ v Y not(Z)) to make g less symmetric.
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4. Each step now adds in the result of the previous step. This
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promotes a faster "avalanche effect".
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5. The order in which input words are accessed in rounds 2 and
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3 is changed, to make these patterns less like each other.
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6. The shift amounts in each round have been approximately
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optimized, to yield a faster "avalanche effect." The shifts in
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different rounds are distinct.
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References
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[1] Rivest, R., "The MD4 Message Digest Algorithm", RFC 1320, MIT and
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RSA Data Security, Inc., April 1992.
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[2] Rivest, R., "The MD4 message digest algorithm", in A.J. Menezes
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and S.A. Vanstone, editors, Advances in Cryptology - CRYPTO '90
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Proceedings, pages 303-311, Springer-Verlag, 1991.
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[3] CCITT Recommendation X.509 (1988), "The Directory -
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Authentication Framework."APPENDIX A - Reference Implementation
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The level of security discussed in this memo is considered to be
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sufficient for implementing very high security hybrid digital-
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signature schemes based on MD5 and a public-key cryptosystem.
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Author's Address
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Ronald L. Rivest Massachusetts Institute of Technology
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Laboratory for Computer Science NE43-324 545 Technology Square
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Cambridge, MA 02139-1986 Phone: (617) 253-5880
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EMail: rivest@theory.lcs.mit.edu
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*****************************************************************************************/
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#ifndef _WX_FILEH__
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class wxFile;
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#endif
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class wxMD5Checksum
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{
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public:
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// interface functions for the RSA MD5 calculation
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static wxString GetMD5(unsigned char* pBuf, unsigned int nLength);
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static wxString GetMD5(wxFile& File);
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static wxString GetMD5(const wxString& strFilePath);
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protected:
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// constructor/destructor
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wxMD5Checksum();
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virtual ~wxMD5Checksum() {};
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// RSA MD5 implementation
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void Transform(unsigned char Block[64]);
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void Update(unsigned char* Input, unsigned long nInputLen);
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wxString Final();
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inline unsigned long RotateLeft(unsigned long x, int n);
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inline void FF( unsigned long& A, unsigned long B, unsigned long C, unsigned long D, unsigned long X, unsigned long S, unsigned long T);
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inline void GG( unsigned long& A, unsigned long B, unsigned long C, unsigned long D, unsigned long X, unsigned long S, unsigned long T);
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inline void HH( unsigned long& A, unsigned long B, unsigned long C, unsigned long D, unsigned long X, unsigned long S, unsigned long T);
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inline void II( unsigned long& A, unsigned long B, unsigned long C, unsigned long D, unsigned long X, unsigned long S, unsigned long T);
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// utility functions
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inline void DWordToByte(unsigned char* Output, unsigned long* Input, unsigned int nLength);
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inline void ByteToDWord(unsigned long* Output, unsigned char* Input, unsigned int nLength);
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private:
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unsigned char m_lpszBuffer[64]; // input buffer
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unsigned long m_nCount[2]; // number of bits, modulo 2^64 (lsb first)
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unsigned long m_lMD5[4]; // MD5 checksum
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};
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#endif
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