MD4C.C__.rar_md4c_哈希计算md4_哈希值_md532位哈希值资源-CSDN文库

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MD4C.C__.rar是一个包含有关MD4哈希计算的资源包，主要关注的是如何使用MD4算法来生成密码或其他数据的哈希值。MD4（Message-Digest Algorithm 4）是由Ron Rivest在1990年设计的一种广泛使用的哈希函数，它将任意长度的输入（也称为预映射或消息）转换为固定长度的输出，通常是128位，通常以32个十六进制数字的形式表示。 MD4算法的工作原理基于一系列复杂的数学和位操作，包括位旋转、异或、加法等。它主要分为四个阶段：初始化、处理消息块、完成和输出。在初始化阶段，MD4会设置一个初始哈希值。在处理消息块阶段，算法将输入消息分块处理，每个块大小为512位。每个块经过多个循环处理，每个循环包含多个独立的位操作。这些中间结果会组合在一起，生成最终的哈希值。 MD4算法虽然曾经被广泛使用，但由于其安全性较低，已被其他更安全的哈希函数如SHA-1和SHA-2系列所取代。MD4的弱点在于容易受到碰撞攻击，即两个不同的输入可能产生相同的哈希值。因此，MD4现在主要用于教学和理解哈希函数的基本原理，而不是用于安全相关的应用。压缩包中的MD4C.C__.htm文件可能是对MD4C函数的文档说明或源代码实现。MD4C可能是MD4的一个C语言实现，提供了计算MD4哈希值的接口。在实际编程中，这样的函数可能会接受一个字符串（比如密码）作为输入，然后返回该字符串的MD4哈希值，通常用于身份验证、数据完整性检查等场景。为了使用MD4C函数，开发者需要理解如何读取和处理输入数据，调用函数进行哈希计算，并正确解析返回的哈希值。在C语言中，这可能涉及到内存管理、字符串操作和错误处理等方面的知识。在实际应用中，需要注意MD4的安全隐患，避免使用MD4进行敏感数据的加密或保护。 MD4是一种早期的哈希算法，尽管存在安全问题，但仍然在理解和学习哈希函数时有其价值。MD4C.C__.rar提供的资源可以帮助开发者了解如何在C语言环境中实现MD4哈希计算，从而深入理解哈希函数的工作机制。

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MD4C.C__.rar （1个子文件）

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<html><head><title>md4.rar MD4C.C</title> <LINK href="/inc/read_style.css" type=text/css rel=stylesheet></head> <body> <p><a href=http://www.pudn.com>www.pudn.com</a> > <a href="http://www.pudn.com/downloads27/sourcecode/windows/file/detail85537.html">md4.rar</a> &gt MD4C.C, change:1992-03-27,size:9311b</p> <script src="/inc/gg_read1.js"></script><BR> <pre name="code" class="C"> /* MD4C.C - RSA Data Security, Inc., MD4 message-digest algorithm */ /* Copyright (C) 1990-2, RSA Data Security, Inc. All rights reserved. License to copy and use this software is granted provided that it is identified as the "RSA Data Security, Inc. MD4 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. MD4 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 "md4.h" /* Constants for MD4Transform routine. */ #define S11 3 #define S12 7 #define S13 11 #define S14 19 #define S21 3 #define S22 5 #define S23 9 #define S24 13 #define S31 3 #define S32 9 #define S33 11 #define S34 15 static void MD4Transform 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 MD4_memcpy PROTO_LIST ((POINTER, POINTER, unsigned int)); static void MD4_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 and H are basic MD4 functions. */ #define F(x, y, z) (((x) & (y)) | ((~x) & (z))) #define G(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z))) #define H(x, y, z) ((x) ^ (y) ^ (z)) /* ROTATE_LEFT rotates x left n bits. */ #define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n)))) /* FF, GG and HH are transformations for rounds 1, 2 and 3 */ /* Rotation is separate from addition to prevent recomputation */ #define FF(a, b, c, d, x, s) { \ (a) += F ((b), (c), (d)) + (x); \ (a) = ROTATE_LEFT ((a), (s)); \ } #define GG(a, b, c, d, x, s) { \ (a) += G ((b), (c), (d)) + (x) + (UINT4)0x5a827999; \ (a) = ROTATE_LEFT ((a), (s)); \ } #define HH(a, b, c, d, x, s) { \ (a) += H ((b), (c), (d)) + (x) + (UINT4)0x6ed9eba1; \ (a) = ROTATE_LEFT ((a), (s)); \ } /* MD4 initialization. Begins an MD4 operation, writing a new context. */ void MD4Init (context) MD4_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; } /* MD4 block update operation. Continues an MD4 message-digest operation, processing another message block, and updating the context. */ void MD4Update (context, input, inputLen) MD4_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) { MD4_memcpy ((POINTER)&context->buffer[index], (POINTER)input, partLen); MD4Transform (context->state, context->buffer); for (i = partLen; i + 63 < inputLen; i += 64) MD4Transform (context->state, &input[i]); index = 0; } else i = 0; /* Buffer remaining input */ MD4_memcpy ((POINTER)&context->buffer[index], (POINTER)&input[i], inputLen-i); } /* MD4 finalization. Ends an MD4 message-digest operation, writing the the message digest and zeroizing the context. */ void MD4Final (digest, context) unsigned char digest[16]; /* message digest */ MD4_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); MD4Update (context, PADDING, padLen); /* Append length (before padding) */ MD4Update (context, bits, 8); /* Store state in digest */ Encode (digest, context->state, 16); /* Zeroize sensitive information. */ MD4_memset ((POINTER)context, 0, sizeof (*context)); } /* MD4 basic transformation. Transforms state based on block. */ static void MD4Transform (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); /* 1 */ FF (d, a, b, c, x[ 1], S12); /* 2 */ FF (c, d, a, b, x[ 2], S13); /* 3 */ FF (b, c, d, a, x[ 3], S14); /* 4 */ FF (a, b, c, d, x[ 4], S11); /* 5 */ FF (d, a, b, c, x[ 5], S12); /* 6 */ FF (c, d, a, b, x[ 6], S13); /* 7 */ FF (b, c, d, a, x[ 7], S14); /* 8 */ FF (a, b, c, d, x[ 8], S11); /* 9 */ FF (d, a, b, c, x[ 9], S12); /* 10 */ FF (c, d, a, b, x[10], S13); /* 11 */ FF (b, c, d, a, x[11], S14); /* 12 */ FF (a, b, c, d, x[12], S11); /* 13 */ FF (d, a, b, c, x[13], S12); /* 14 */ FF (c, d, a, b, x[14], S13); /* 15 */ FF (b, c, d, a, x[15], S14); /* 16 */ /* Round 2 */ GG (a, b, c, d, x[ 0], S21); /* 17 */ GG (d, a, b, c, x[ 4], S22); /* 18 */ GG (c, d, a, b, x[ 8], S23); /* 19 */ GG (b, c, d, a, x[12], S24); /* 20 */ GG (a, b, c, d, x[ 1], S21); /* 21 */ GG (d, a, b, c, x[ 5], S22); /* 22 */ GG (c, d, a, b, x[ 9], S23); /* 23 */ GG (b, c, d, a, x[13], S24); /* 24 */ GG (a, b, c, d, x[ 2], S21); /* 25 */ GG (d, a, b, c, x[ 6], S22); /* 26 */ GG (c, d, a, b, x[10], S23); /* 27 */ GG (b, c, d, a, x[14], S24); /* 28 */ GG (a, b, c, d, x[ 3], S21); /* 29 */ GG (d, a, b, c, x[ 7], S22); /* 30 */ GG (c, d, a, b, x[11], S23); /* 31 */ GG (b, c, d, a, x[15], S24); /* 32 */ /* Round 3 */ HH (a, b, c, d, x[ 0], S31); /* 33 */ HH (d, a, b, c, x[ 8], S32); /* 34 */ HH (c, d, a, b, x[ 4], S33); /* 35 */ HH (b, c, d, a, x[12], S34); /* 36 */ HH (a, b, c, d, x[ 2], S31); /* 37 */ HH (d, a, b, c, x[10], S32); /* 38 */ HH (c, d, a, b, x[ 6], S33); /* 39 */ HH

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