1094 lines
34 KiB
HTML
1094 lines
34 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
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<title>The MD5 Message-Digest Algorithm</title>
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<meta name="author" content="John Walker" />
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<meta name="description" content="RFC 1321: The MD5 Message-Digest Algorithm" />
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<meta name="keywords" content="md5, message, digest" />
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<meta name="robots" content="noindex" />
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<link rel="stylesheet" href="/documents/styles/standard_screen.css" type="text/css" />
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</head>
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<body class="standard">
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<table>
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<tr>
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<td width="10%" valign="top">
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<a href="./"><img src="md5s.png" width="95" height="50" alt="MD5 Main Page" border="0" /></a></td>
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<td width="80%">
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<center>
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<h1>The MD5 Message-Digest Algorithm</h1>
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<h4>
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Network Working Group<br />
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Request for Comments: 1321<br />
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<br />
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R. Rivest<br />
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<a href="http://web.mit.edu/">MIT</a> <a href="http://www.lcs.mit.edu/">Laboratory for Computer Science</a><br />
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and <a href="http://www.rsa.com/">RSA Data Security, Inc.</a><br />
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April 1992
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</h4>
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</center>
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</td>
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<td width="10%"> </td>
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</tr>
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</table>
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<hr />
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<h3>Status of this Memo</h3>
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This memo provides information for the Internet community. It does
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not specify an Internet standard. Distribution of this memo is
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unlimited.
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<h3>Acknowlegements</h3>
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We would like to thank Don Coppersmith, Burt Kaliski, Ralph Merkle,
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David Chaum, and Noam Nisan for numerous helpful comments and
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suggestions.
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<h3>Table of Contents</h3>
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<dl>
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<dt></dt> <dd><a href="#1">1. Executive Summary</a></dd>
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<dt></dt> <dd><a href="#2">2. Terminology and Notation</a></dd>
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<dt></dt> <dd><a href="#3">3. MD5 Algorithm Description</a></dd>
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<dt></dt> <dd><a href="#4">4. Summary</a></dd>
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<dt></dt> <dd><a href="#5">5. Differences Between MD4 and MD5</a></dd>
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<dt></dt> <dd><a href="#References">References</a></dd>
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<dt></dt> <dd><a href="#AppendixA">APPENDIX A - Reference Implementation</a></dd>
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<dt></dt> <dd><a href="#Security">Security Considerations</a></dd>
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<dt></dt> <dd><a href="#Author">Author's Address</a></dd>
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</dl>
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<h3><a class="i" name="1">1. Executive Summary</a></h3>
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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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<p />
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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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<p />
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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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<p />
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For OSI-based applications, MD5's object identifier is
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<blockquote>
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md5 OBJECT IDENTIFIER ::=<br />
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iso(1) member-body(2) US(840) rsadsi(113549) digestAlgorithm(2) 5}
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</blockquote>
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In the X.509 type AlgorithmIdentifier [3], the parameters for MD5
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should have type NULL.
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<h3><a class="i" name="2">2. Terminology and Notation</a></h3>
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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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<p />
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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
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power.
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<p />
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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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<h3><a class="i" name="3">3. MD5 Algorithm Description</a></h3>
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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:
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<blockquote>
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m_0 m_1 ... m_{b-1}
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</blockquote>
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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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<h4>3.1 Step 1. Append Padding Bits</h4>
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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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<p />
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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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<h4>3.2 Step 2. Append Length</h4>
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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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<p />
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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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<h4>3.3 Step 3. Initialize MD Buffer</h4>
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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
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first):
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<blockquote>
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word A: 01 23 45 67<br />
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word B: 89 ab cd ef<br />
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word C: fe dc ba 98<br />
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word D: 76 54 32 10
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</blockquote>
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<h4>3.4 Step 4. Process Message in 16-Word Blocks</h4>
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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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<blockquote>
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F(X,Y,Z) = XY v not(X) Z<br />
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G(X,Y,Z) = XZ v Y not(Z)<br />
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H(X,Y,Z) = X xor Y xor Z<br />
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I(X,Y,Z) = Y xor (X v not(Z))
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</blockquote>
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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
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unbiased.
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<p />
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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
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inputs.
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<p />
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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 <a href="#AppendixA">appendix</a>.
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<p />
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Do the following:
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<p />
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<pre>
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/* Process each 16-word block. */
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For i = 0 to N/16-1 do
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/* 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
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BB = B
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CC = C
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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
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B = B + BB
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C = C + CC
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D = D + DD
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end /* of loop on i */
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</pre>
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<h4>3.5 Step 5. Output</h4>
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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
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of D.
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<p />
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This completes the description of MD5. A reference implementation in
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C is given in the appendix.
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<h3><a class="i" name="4">4. Summary</a></h3>
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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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<h3><a class="i" name="5">5. Differences Between MD4 and MD5</a></h3>
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The following are the differences between MD4 and MD5:
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<p />
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<ol>
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<li> A fourth round has been added.</li>
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<li> Each step now has a unique additive constant.</li>
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<li> 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.</li>
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<li> Each step now adds in the result of the previous step. This
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promotes a faster "avalanche effect".</li>
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<li> 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.</li>
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<li> 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.</li>
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</ol>
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<h3><a class="i" name="References">References</a></h3>
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<dl>
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<dt>[1]</dt> <dd>Rivest, R., "The MD4 Message Digest Algorithm", RFC 1320, MIT and
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RSA Data Security, Inc., April 1992.</dd>
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<dt>[2]</dt> <dd>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.</dd>
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<dt>[3]</dt> <dd>CCITT Recommendation X.509 (1988), "The Directory -
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Authentication Framework."</dd>
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</dl>
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<h3><a class="i" name="AppendixA">APPENDIX A - Reference Implementation</a></h3>
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This appendix contains the following files taken from RSAREF: A
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Cryptographic Toolkit for Privacy-Enhanced Mail:
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<blockquote>
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<a href="#A.1">global.h</a> -- global header file<br />
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<a href="#A.2">md5.h</a> -- header file for MD5<br />
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<a href="#A.3">md5c.c</a> -- source code for MD5
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</blockquote>
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For more information on RSAREF, send email
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to <<a href="mailto:rsaref@rsa.com">rsaref@rsa.com</a>>.
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<p />
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The appendix also includes the following file:
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<blockquote>
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<a href="#A.4">mddriver.c</a> -- test driver for MD2, MD4 and MD5
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</blockquote>
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The driver compiles for MD5 by default but can compile for MD2 or MD4
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if the symbol MD is defined on the C compiler command line as 2 or 4.
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<p />
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The implementation is portable and should work on many different
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plaforms. However, it is not difficult to optimize the
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implementation on particular platforms, an exercise left to the
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reader. For example, on "little-endian" platforms where the
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lowest-addressed byte in a 32-bit word is the least significant and
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there are no alignment restrictions, the call to Decode in
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MD5Transform can be replaced with a typecast.
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<h4><a class="i" name="A.1">A.1 global.h</a></h4>
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<pre>
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/* GLOBAL.H - RSAREF types and constants
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*/
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/* PROTOTYPES should be set to one if and only if the compiler supports
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function argument prototyping.
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The following makes PROTOTYPES default to 0 if it has not already
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been defined with C compiler flags.
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*/
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#ifndef PROTOTYPES
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#define PROTOTYPES 0
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#endif
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/* POINTER defines a generic pointer type */
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typedef unsigned char *POINTER;
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/* UINT2 defines a two byte word */
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typedef unsigned short int UINT2;
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/* UINT4 defines a four byte word */
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typedef unsigned long int UINT4;
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/* PROTO_LIST is defined depending on how PROTOTYPES is defined above.
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If using PROTOTYPES, then PROTO_LIST returns the list, otherwise it
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returns an empty list.
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*/
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#if PROTOTYPES
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#define PROTO_LIST(list) list
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#else
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#define PROTO_LIST(list) ()
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#endif
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</pre>
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<h4><a class="i" name="A.2">A.2 md5.h</a></h4>
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<pre>
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/* MD5.H - header file for MD5C.C
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*/
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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
|
|
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"
|
|
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.
|
|
*/
|
|
|
|
/* MD5 context. */
|
|
typedef struct {
|
|
UINT4 state[4]; /* state (ABCD) */
|
|
UINT4 count[2]; /* number of bits, modulo 2^64 (lsb first) */
|
|
unsigned char buffer[64]; /* input buffer */
|
|
} MD5_CTX;
|
|
|
|
void MD5Init PROTO_LIST ((MD5_CTX *));
|
|
void MD5Update PROTO_LIST
|
|
((MD5_CTX *, unsigned char *, unsigned int));
|
|
void MD5Final PROTO_LIST ((unsigned char [16], MD5_CTX *));
|
|
</pre>
|
|
|
|
<h4><a class="i" name="A.3">A.3 md5c.c</a></h4>
|
|
|
|
<pre>
|
|
|
|
/* MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
|
|
*/
|
|
|
|
/* 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.
|
|
*/
|
|
|
|
#include "global.h"
|
|
#include "md5.h"
|
|
|
|
/* Constants for MD5Transform routine.
|
|
*/
|
|
|
|
#define S11 7
|
|
#define S12 12
|
|
#define S13 17
|
|
#define S14 22
|
|
#define S21 5
|
|
#define S22 9
|
|
#define S23 14
|
|
#define S24 20
|
|
#define S31 4
|
|
#define S32 11
|
|
#define S33 16
|
|
#define S34 23
|
|
#define S41 6
|
|
#define S42 10
|
|
#define S43 15
|
|
#define S44 21
|
|
|
|
static void MD5Transform PROTO_LIST ((UINT4 [4], unsigned char [64]));
|
|
static void Encode PROTO_LIST
|
|
((unsigned char *, UINT4 *, unsigned int));
|
|
static void Decode PROTO_LIST
|
|
((UINT4 *, unsigned char *, unsigned int));
|
|
static void MD5_memcpy PROTO_LIST ((POINTER, POINTER, unsigned int));
|
|
static void MD5_memset PROTO_LIST ((POINTER, int, unsigned int));
|
|
|
|
static unsigned char PADDING[64] = {
|
|
0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
|
|
};
|
|
|
|
/* F, G, H and I are basic MD5 functions.
|
|
*/
|
|
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
|
|
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
|
|
#define H(x, y, z) ((x) ^ (y) ^ (z))
|
|
#define I(x, y, z) ((y) ^ ((x) | (~z)))
|
|
|
|
/* ROTATE_LEFT rotates x left n bits.
|
|
*/
|
|
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
|
|
|
|
/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
|
|
Rotation is separate from addition to prevent recomputation.
|
|
*/
|
|
#define FF(a, b, c, d, x, s, ac) { \
|
|
(a) += F ((b), (c), (d)) + (x) + (UINT4)(ac); \
|
|
(a) = ROTATE_LEFT ((a), (s)); \
|
|
(a) += (b); \
|
|
}
|
|
#define GG(a, b, c, d, x, s, ac) { \
|
|
(a) += G ((b), (c), (d)) + (x) + (UINT4)(ac); \
|
|
(a) = ROTATE_LEFT ((a), (s)); \
|
|
(a) += (b); \
|
|
}
|
|
#define HH(a, b, c, d, x, s, ac) { \
|
|
(a) += H ((b), (c), (d)) + (x) + (UINT4)(ac); \
|
|
(a) = ROTATE_LEFT ((a), (s)); \
|
|
(a) += (b); \
|
|
}
|
|
#define II(a, b, c, d, x, s, ac) { \
|
|
(a) += I ((b), (c), (d)) + (x) + (UINT4)(ac); \
|
|
(a) = ROTATE_LEFT ((a), (s)); \
|
|
(a) += (b); \
|
|
}
|
|
|
|
/* MD5 initialization. Begins an MD5 operation, writing a new context.
|
|
*/
|
|
void MD5Init (context)
|
|
MD5_CTX *context; /* context */
|
|
{
|
|
context->count[0] = context->count[1] = 0;
|
|
/* Load magic initialization constants.
|
|
*/
|
|
context->state[0] = 0x67452301;
|
|
context->state[1] = 0xefcdab89;
|
|
context->state[2] = 0x98badcfe;
|
|
context->state[3] = 0x10325476;
|
|
}
|
|
|
|
/* MD5 block update operation. Continues an MD5 message-digest
|
|
operation, processing another message block, and updating the
|
|
context.
|
|
*/
|
|
void MD5Update (context, input, inputLen)
|
|
MD5_CTX *context; /* context */
|
|
unsigned char *input; /* input block */
|
|
unsigned int inputLen; /* length of input block */
|
|
{
|
|
unsigned int i, index, partLen;
|
|
|
|
/* Compute number of bytes mod 64 */
|
|
index = (unsigned int)((context->count[0] >> 3) & 0x3F);
|
|
|
|
/* Update number of bits */
|
|
if ((context->count[0] += ((UINT4)inputLen << 3))
|
|
< ((UINT4)inputLen << 3))
|
|
context->count[1]++;
|
|
context->count[1] += ((UINT4)inputLen >> 29);
|
|
|
|
partLen = 64 - index;
|
|
|
|
/* Transform as many times as possible.
|
|
*/
|
|
if (inputLen >= partLen) {
|
|
MD5_memcpy
|
|
((POINTER)&context->buffer[index], (POINTER)input, partLen);
|
|
MD5Transform (context->state, context->buffer);
|
|
|
|
for (i = partLen; i + 63 < inputLen; i += 64)
|
|
MD5Transform (context->state, &input[i]);
|
|
|
|
index = 0;
|
|
}
|
|
else
|
|
i = 0;
|
|
|
|
/* Buffer remaining input */
|
|
MD5_memcpy
|
|
((POINTER)&context->buffer[index], (POINTER)&input[i],
|
|
inputLen-i);
|
|
}
|
|
|
|
/* MD5 finalization. Ends an MD5 message-digest operation, writing the
|
|
the message digest and zeroizing the context.
|
|
*/
|
|
void MD5Final (digest, context)
|
|
unsigned char digest[16]; /* message digest */
|
|
MD5_CTX *context; /* context */
|
|
{
|
|
unsigned char bits[8];
|
|
unsigned int index, padLen;
|
|
|
|
/* Save number of bits */
|
|
Encode (bits, context->count, 8);
|
|
|
|
/* Pad out to 56 mod 64.
|
|
*/
|
|
index = (unsigned int)((context->count[0] >> 3) & 0x3f);
|
|
padLen = (index < 56) ? (56 - index) : (120 - index);
|
|
MD5Update (context, PADDING, padLen);
|
|
|
|
/* Append length (before padding) */
|
|
MD5Update (context, bits, 8);
|
|
|
|
/* Store state in digest */
|
|
Encode (digest, context->state, 16);
|
|
|
|
/* Zeroize sensitive information.
|
|
*/
|
|
MD5_memset ((POINTER)context, 0, sizeof (*context));
|
|
}
|
|
|
|
/* MD5 basic transformation. Transforms state based on block.
|
|
*/
|
|
static void MD5Transform (state, block)
|
|
UINT4 state[4];
|
|
unsigned char block[64];
|
|
{
|
|
UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];
|
|
|
|
Decode (x, block, 64);
|
|
|
|
/* Round 1 */
|
|
FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
|
|
FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
|
|
FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
|
|
FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
|
|
FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
|
|
FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
|
|
FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
|
|
FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
|
|
FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
|
|
FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
|
|
FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
|
|
FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
|
|
FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
|
|
FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
|
|
FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
|
|
FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
|
|
|
|
/* Round 2 */
|
|
GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
|
|
GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
|
|
GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
|
|
GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
|
|
GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
|
|
GG (d, a, b, c, x[10], S22, 0x2441453); /* 22 */
|
|
GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
|
|
GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
|
|
GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
|
|
GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
|
|
GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
|
|
GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
|
|
GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
|
|
GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
|
|
GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
|
|
GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
|
|
|
|
/* Round 3 */
|
|
HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
|
|
HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
|
|
HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
|
|
HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
|
|
HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
|
|
HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
|
|
HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
|
|
HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
|
|
HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
|
|
HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
|
|
HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
|
|
HH (b, c, d, a, x[ 6], S34, 0x4881d05); /* 44 */
|
|
HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
|
|
HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
|
|
HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
|
|
HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */
|
|
|
|
/* Round 4 */
|
|
II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
|
|
II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
|
|
II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
|
|
II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
|
|
II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
|
|
II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
|
|
II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
|
|
II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
|
|
II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
|
|
II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
|
|
II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
|
|
II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
|
|
II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
|
|
II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
|
|
II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
|
|
II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */
|
|
|
|
state[0] += a;
|
|
state[1] += b;
|
|
state[2] += c;
|
|
state[3] += d;
|
|
|
|
/* Zeroize sensitive information.
|
|
*/
|
|
MD5_memset ((POINTER)x, 0, sizeof (x));
|
|
}
|
|
|
|
/* Encodes input (UINT4) into output (unsigned char). Assumes len is
|
|
a multiple of 4.
|
|
*/
|
|
static void Encode (output, input, len)
|
|
unsigned char *output;
|
|
UINT4 *input;
|
|
unsigned int len;
|
|
{
|
|
unsigned int i, j;
|
|
|
|
for (i = 0, j = 0; j < len; i++, j += 4) {
|
|
output[j] = (unsigned char)(input[i] & 0xff);
|
|
output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
|
|
output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
|
|
output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
|
|
}
|
|
}
|
|
|
|
/* Decodes input (unsigned char) into output (UINT4). Assumes len is
|
|
a multiple of 4.
|
|
*/
|
|
static void Decode (output, input, len)
|
|
UINT4 *output;
|
|
unsigned char *input;
|
|
unsigned int len;
|
|
{
|
|
unsigned int i, j;
|
|
|
|
for (i = 0, j = 0; j < len; i++, j += 4)
|
|
output[i] = ((UINT4)input[j]) | (((UINT4)input[j+1]) << 8) |
|
|
(((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);
|
|
}
|
|
|
|
/* Note: Replace "for loop" with standard memcpy if possible.
|
|
*/
|
|
|
|
static void MD5_memcpy (output, input, len)
|
|
POINTER output;
|
|
POINTER input;
|
|
unsigned int len;
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < len; i++)
|
|
output[i] = input[i];
|
|
}
|
|
|
|
/* Note: Replace "for loop" with standard memset if possible.
|
|
*/
|
|
static void MD5_memset (output, value, len)
|
|
POINTER output;
|
|
int value;
|
|
unsigned int len;
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < len; i++)
|
|
((char *)output)[i] = (char)value;
|
|
}
|
|
</pre>
|
|
|
|
<h4><a class="i" name="A.4">A.4 mddriver.c</a></h4>
|
|
|
|
<pre>
|
|
/* MDDRIVER.C - test driver for MD2, MD4 and MD5
|
|
*/
|
|
|
|
/* 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.
|
|
*/
|
|
|
|
/* The following makes MD default to MD5 if it has not already been
|
|
defined with C compiler flags.
|
|
*/
|
|
#ifndef MD
|
|
#define MD MD5
|
|
#endif
|
|
|
|
#include <stdio.h>
|
|
#include <time.h>
|
|
#include <string.h>
|
|
#include "global.h"
|
|
#if MD == 2
|
|
#include "md2.h"
|
|
#endif
|
|
#if MD == 4
|
|
#include "md4.h"
|
|
#endif
|
|
#if MD == 5
|
|
#include "md5.h"
|
|
#endif
|
|
|
|
/* Length of test block, number of test blocks.
|
|
*/
|
|
#define TEST_BLOCK_LEN 1000
|
|
#define TEST_BLOCK_COUNT 1000
|
|
|
|
static void MDString PROTO_LIST ((char *));
|
|
static void MDTimeTrial PROTO_LIST ((void));
|
|
static void MDTestSuite PROTO_LIST ((void));
|
|
static void MDFile PROTO_LIST ((char *));
|
|
static void MDFilter PROTO_LIST ((void));
|
|
static void MDPrint PROTO_LIST ((unsigned char [16]));
|
|
|
|
#if MD == 2
|
|
#define MD_CTX MD2_CTX
|
|
#define MDInit MD2Init
|
|
#define MDUpdate MD2Update
|
|
#define MDFinal MD2Final
|
|
#endif
|
|
#if MD == 4
|
|
#define MD_CTX MD4_CTX
|
|
#define MDInit MD4Init
|
|
#define MDUpdate MD4Update
|
|
#define MDFinal MD4Final
|
|
#endif
|
|
#if MD == 5
|
|
#define MD_CTX MD5_CTX
|
|
#define MDInit MD5Init
|
|
#define MDUpdate MD5Update
|
|
#define MDFinal MD5Final
|
|
#endif
|
|
|
|
/* Main driver.
|
|
|
|
Arguments (may be any combination):
|
|
-sstring - digests string
|
|
-t - runs time trial
|
|
-x - runs test script
|
|
filename - digests file
|
|
(none) - digests standard input
|
|
*/
|
|
int main (argc, argv)
|
|
int argc;
|
|
char *argv[];
|
|
{
|
|
int i;
|
|
|
|
if (argc > 1)
|
|
for (i = 1; i < argc; i++)
|
|
if (argv[i][0] == '-' && argv[i][1] == 's')
|
|
MDString (argv[i] + 2);
|
|
else if (strcmp (argv[i], "-t") == 0)
|
|
MDTimeTrial ();
|
|
else if (strcmp (argv[i], "-x") == 0)
|
|
MDTestSuite ();
|
|
else
|
|
MDFile (argv[i]);
|
|
else
|
|
MDFilter ();
|
|
|
|
return (0);
|
|
}
|
|
|
|
/* Digests a string and prints the result.
|
|
*/
|
|
static void MDString (string)
|
|
char *string;
|
|
{
|
|
MD_CTX context;
|
|
unsigned char digest[16];
|
|
unsigned int len = strlen (string);
|
|
|
|
MDInit (&context);
|
|
MDUpdate (&context, string, len);
|
|
MDFinal (digest, &context);
|
|
|
|
printf ("MD%d (\"%s\") = ", MD, string);
|
|
MDPrint (digest);
|
|
printf ("\n");
|
|
}
|
|
|
|
/* Measures the time to digest TEST_BLOCK_COUNT TEST_BLOCK_LEN-byte
|
|
blocks.
|
|
*/
|
|
static void MDTimeTrial ()
|
|
{
|
|
MD_CTX context;
|
|
time_t endTime, startTime;
|
|
unsigned char block[TEST_BLOCK_LEN], digest[16];
|
|
unsigned int i;
|
|
|
|
printf
|
|
("MD%d time trial. Digesting %d %d-byte blocks ...", MD,
|
|
TEST_BLOCK_LEN, TEST_BLOCK_COUNT);
|
|
|
|
/* Initialize block */
|
|
for (i = 0; i < TEST_BLOCK_LEN; i++)
|
|
block[i] = (unsigned char)(i & 0xff);
|
|
|
|
/* Start timer */
|
|
time (&startTime);
|
|
|
|
/* Digest blocks */
|
|
MDInit (&context);
|
|
for (i = 0; i < TEST_BLOCK_COUNT; i++)
|
|
MDUpdate (&context, block, TEST_BLOCK_LEN);
|
|
MDFinal (digest, &context);
|
|
|
|
/* Stop timer */
|
|
time (&endTime);
|
|
|
|
printf (" done\n");
|
|
printf ("Digest = ");
|
|
MDPrint (digest);
|
|
printf ("\nTime = %ld seconds\n", (long)(endTime-startTime));
|
|
printf
|
|
("Speed = %ld bytes/second\n",
|
|
(long)TEST_BLOCK_LEN * (long)TEST_BLOCK_COUNT/(endTime-startTime));
|
|
}
|
|
|
|
/* Digests a reference suite of strings and prints the results.
|
|
*/
|
|
static void MDTestSuite ()
|
|
{
|
|
printf ("MD%d test suite:\n", MD);
|
|
|
|
MDString ("");
|
|
MDString ("a");
|
|
MDString ("abc");
|
|
MDString ("message digest");
|
|
MDString ("abcdefghijklmnopqrstuvwxyz");
|
|
MDString
|
|
("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789");
|
|
MDString
|
|
("1234567890123456789012345678901234567890\
|
|
1234567890123456789012345678901234567890");
|
|
}
|
|
|
|
/* Digests a file and prints the result.
|
|
*/
|
|
static void MDFile (filename)
|
|
char *filename;
|
|
{
|
|
FILE *file;
|
|
MD_CTX context;
|
|
int len;
|
|
unsigned char buffer[1024], digest[16];
|
|
|
|
if ((file = fopen (filename, "rb")) == NULL)
|
|
printf ("%s can't be opened\n", filename);
|
|
|
|
else {
|
|
MDInit (&context);
|
|
while (len = fread (buffer, 1, 1024, file))
|
|
MDUpdate (&context, buffer, len);
|
|
MDFinal (digest, &context);
|
|
|
|
fclose (file);
|
|
|
|
printf ("MD%d (%s) = ", MD, filename);
|
|
MDPrint (digest);
|
|
printf ("\n");
|
|
}
|
|
}
|
|
|
|
/* Digests the standard input and prints the result.
|
|
*/
|
|
static void MDFilter ()
|
|
{
|
|
MD_CTX context;
|
|
int len;
|
|
unsigned char buffer[16], digest[16];
|
|
|
|
MDInit (&context);
|
|
while (len = fread (buffer, 1, 16, stdin))
|
|
MDUpdate (&context, buffer, len);
|
|
MDFinal (digest, &context);
|
|
|
|
MDPrint (digest);
|
|
printf ("\n");
|
|
}
|
|
|
|
/* Prints a message digest in hexadecimal.
|
|
*/
|
|
static void MDPrint (digest)
|
|
unsigned char digest[16];
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < 16; i++)
|
|
printf ("%02x", digest[i]);
|
|
}
|
|
</pre>
|
|
|
|
<h4><a class="i" name="A.5">A.5 Test suite</a></h4>
|
|
|
|
The MD5 test suite (driver option "-x") should print the following
|
|
results:
|
|
|
|
<p />
|
|
<pre>
|
|
MD5 test suite:
|
|
MD5 ("") = d41d8cd98f00b204e9800998ecf8427e
|
|
MD5 ("a") = 0cc175b9c0f1b6a831c399e269772661
|
|
MD5 ("abc") = 900150983cd24fb0d6963f7d28e17f72
|
|
MD5 ("message digest") = f96b697d7cb7938d525a2f31aaf161d0
|
|
MD5 ("abcdefghijklmnopqrstuvwxyz") = c3fcd3d76192e4007dfb496cca67e13b
|
|
MD5 ("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") =
|
|
d174ab98d277d9f5a5611c2c9f419d9f
|
|
MD5 ("12345678901234567890123456789012345678901234567890123456789012345678901234567890") = 57edf4a22be3c955ac49da2e2107b67a
|
|
</pre>
|
|
|
|
<h3><a class="i" name="Security">Security Considerations</a></h3>
|
|
|
|
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.
|
|
|
|
<h3><a class="i" name="Author">Author's Address</a></h3>
|
|
|
|
<blockquote>
|
|
Ronald L. Rivest<br />
|
|
Massachusetts Institute of Technology<br />
|
|
Laboratory for Computer Science<br />
|
|
NE43-324<br />
|
|
545 Technology Square<br />
|
|
Cambridge, MA 02139-1986<p />
|
|
|
|
Phone: (617) 253-5880<br />
|
|
EMail: rivest@theory.lcs.mit.edu
|
|
</blockquote>
|
|
|
|
<p />
|
|
<hr />
|
|
<h3 class="nav"><a href="./">Back to MD5 main page</a></h3>
|
|
<h3 class="nav"><a href="/">Fourmilab home page</a></h3>
|
|
</body>
|
|
</html>
|