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