一、实验目的 通过实际编程了解MD5算法的加密和解密过程，加深对Hash算法的认识。
二、实验原理 Hash函数是将任意长的数字串转换成一个较短的定长输出数字串的函数，输出的结果称为Hash值。Hash函数具有如下特点：
(1)快速性：对于任意一个输入值x，由Hash函数H(x)，计算Hash值y，即y=H(x)，是非常容易的。
(2)单向性：对于任意一个输出值y，希望反向推出输入值x，使得y=H(x)，是非常困难的。
(3)无碰撞性：对任意给定的数据块x，希望找到一个y，满足H(x)=H(y)，且x≠y，具有计算的不可行性。
Hash函数可用于数字签名、消息的完整性检测、消息的起源认证检测等。现在常用的Hash算法有MD5、SHA-1等。下面从MD5入手来介绍Hash算法的实现机制。
MD系列单向散列函数是由Ron Rivest设计的，MD5算法对任意长度的输入值处理后产生128位的输出值。MD5算法的实现步骤如下:
在MD5算法中，首先需要对信息进行填充，使其字节长度与448模512同余，即信息的字节长度扩展至nx512+448，11为一个正整数。填充的方法如下：在信息的后面填充第一位为1，其余各位均为0，直到满足上面的条件时才停止用0对信息填充。然后，再在这个结果后面附加一个以64位二进制表示的填充前信息长度。经过这两步的处理，现在的信息字节长度为n*512+448+64=(n+1)*512，即长度恰好是512的整数倍，这样做的目的是为满足后面处理中对信息长度的要求。n个分组中第q个分组表示为Yq。MD5中有A、B、C、D，4个32位被称作链接变量的整数参数，它们的初始值分别为：
A=01234567，B=89abcdef,C=fedcba98，D=76543210
当设置好这4个链接变量后，就开始进入算法的4轮循环运算。循环的次数是信息中512位信息分组数目。首先将上面4个链接变量复制到另外4个变量中：A到AA，B到BB，C到CC，D到DD，以备后面进行处理。
然后进入主循环，主循环有4轮，每轮循环都很相似。第1轮进行16次操作，每次操作对A、B、C和D中的其中3个作一次非线性函数运算，然后将所得结果加上第4个变量，文本的一个子分组和一个常数。再将所得结果向左循环移S位，并加上A、B、C或D其中之一。最后用该结果取代A、B、C或D其中之一。
以下是每次操作中用到的4个非线性函数(每轮一个)。
M[j]表示在第q个512位数据块中的第j个32位子分组，0≤j≤15。
常数T[i]可以有如下选择，在第i步中，T[i]是4294967296*abs(sin(i))的整数部分(注：4294967296=232。)，i的单位是弧度。其中，T[i]是32位的随机数源，它消除了输入数据中任何规律性的特征。
表4-1说明了四轮主循环中每轮16步操作的具体步骤。
所有这些完成之后，将A、B、C、D分别加上AA、BB、CC、DD。然后用下一分组数据继续运行算法，最后的输出是A、B、C和D的级联。
算法分析
根据附录中有关MD5算法的头文件md5．h和实现文件md5．c，根据所提供的文件分析MD5算法的实现过程。
下面简单介绍所用到的结构体变量和函数(见表1-4)。程序中用到的结构体变量如下：
typedef struct md5_state{
ulong64 length;
ulong32 state[4],curlen;
unsigned char buf[64];
}md5_state;
length记录已经处理过的位数，curlen记录已经处理过的字节数，数组state存储上面所说的4个链接变量，buf作为处理过程中的缓存。
程序中用到的函数如下：
(1)void md5_init(md5_state * md)
函数名称：初始化函数。
参数说明：
md指向一个上面所提到的结构体变量。初始化时把curlen和length置为0，并把4个链接变量储存到state中。
(2)int md5_process(md5_state * md，const unsigned char * buf ,unsigned long len)
函数名称：处理函数。
参数说明：
md指向经过初始化函数处理过的一个结构体变量。
buf指向待处理的信息。
len是buf中信息的长度，以字节为单位。
这个函数对待处理的信息以512位为单位进行压缩，不足的部分存储在结构体的buf中，并且用len来指示信息的末尾，这样下次调用时会接着上一次的结果进行。
(3)int md5_done(md5_state * md，unsigned char * Hash)
函数名称：完成函数。
参数说明：md指向上面所处理过的结构体。
Hash指向存储结果的缓冲区。 这个函数对未完成的信息先进行padding操作，然后处理，并把最终结果存在Hash指向的缓冲区中。
(4)int md5_test(void)
函数名称：测试函数。 这个函数对上面的3个函数进行测试。函数内部定义了一组信息和Hash结果一一对应的数组。通过调用上面的3个函数，并把结果和正确结果相比较，可以判断程序正确与否。
实验代码：
//MD5文件头
#ifndef CRYPT_H_
#define CRYPT_H_
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <ctype.h>
#include <limits.h>
/* Use small code where possible */
#define SMALL_CODE
/* Enable self-test test vector checking */
#define LTC_TEST
#define MD5
#ifdef __cplusplus
extern "C" {
#endif
/* version */
#define CRYPT 0x0096
#define SCRYPT "0.96"
/* error codes [will be expanded in future releases] */
enum {
CRYPT_OK=0, /* Result OK */
CRYPT_FAIL_TESTVECTOR, /* Algorithm failed test vectors */
CRYPT_INVALID_ARG, /* Generic invalid argument */
};
/* type of argument checking, 0=default, 1=fatal and 2=none */
#define ARGTYPE 0
#ifdef _MSC_VER
#define CONST64(n) n ## ui64
typedef unsigned __int64 ulong64;
#else
#define CONST64(n) n ## ULL
typedef unsigned long long ulong64;
#endif
typedef unsigned long ulong32;
/* Controls endianess and size of registers. Leave uncommented to get platform neutral [slower] code */
/* detect x86-32 machines somewhat */
#if defined(INTEL_CC) || (defined(_MSC_VER) && defined(WIN32)) || (defined(__GNUC__) && (defined(__DJGPP__) || defined(__CYGWIN__) || defined(__MINGW32__) || defined(__i386__)))
#define ENDIAN_LITTLE
#define ENDIAN_32BITWORD
#endif
/* detects MIPS R5900 processors (PS2) */
#if (defined(__R5900) || defined(R5900) || defined(__R5900__)) && (defined(_mips) || defined(__mips__) || defined(mips))
#define ENDIAN_LITTLE
#define ENDIAN_64BITWORD
#endif
/* #define ENDIAN_LITTLE */
/* #define ENDIAN_BIG */
/* #define ENDIAN_32BITWORD */
/* #define ENDIAN_64BITWORD */
#if (defined(ENDIAN_BIG) || defined(ENDIAN_LITTLE)) && !(defined(ENDIAN_32BITWORD) || defined(ENDIAN_64BITWORD))
#error You must specify a word size as well as endianess in mycrypt_cfg.h
#endif
#if !(defined(ENDIAN_BIG) || defined(ENDIAN_LITTLE))
#define ENDIAN_NEUTRAL
#endif
#ifdef ENDIAN_NEUTRAL
#define STORE32L(x, y) \
{ (y)[3] = (unsigned char)(((x)>>24)&255); (y)[2] = (unsigned char)(((x)>>16)&255); \
(y)[1] = (unsigned char)(((x)>>8)&255); (y)[0] = (unsigned char)((x)&255); }
#define LOAD32L(x, y) \
{ x = ((unsigned long)((y)[3] & 255)<<24) | \
((unsigned long)((y)[2] & 255)<<16) | \
((unsigned long)((y)[1] & 255)<<8) | \
((unsigned long)((y)[0] & 255)); }
#define STORE64L(x, y) \
{ (y)[7] = (unsigned char)(((x)>>56)&255); (y)[6] = (unsigned char)(((x)>>48)&255); \
(y)[5] = (unsigned char)(((x)>>40)&255); (y)[4] = (unsigned char)(((x)>>32)&255); \
(y)[3] = (unsigned char)(((x)>>24)&255); (y)[2] = (unsigned char)(((x)>>16)&255); \
(y)[1] = (unsigned char)(((x)>>8)&255); (y)[0] = (unsigned char)((x)&255); }
#define LOAD64L(x, y) \
{ x = (((ulong64)((y)[7] & 255))<<56)|(((ulong64)((y)[6] & 255))<<48)| \
(((ulong64)((y)[5] & 255))<<40)|(((ulong64)((y)[4] & 255))<<32)| \
(((ulong64)((y)[3] & 255))<<24)|(((ulong64)((y)[2] & 255))<<16)| \
(((ulong64)((y)[1] & 255))<<8)|(((ulong64)((y)[0] & 255))); }
#define STORE32H(x, y) \
{ (y)[0] = (unsigned char)(((x)>>24)&255); (y)[1] = (unsigned char)(((x)>>16)&255); \
(y)[2] = (unsigned char)(((x)>>8)&255); (y)[3] = (unsigned char)((x)&255); }
#define LOAD32H(x, y) \
{ x = ((unsigned long)((y)[0] & 255)<<24) | \
((unsigned long)((y)[1] & 255)<<16) | \
((unsigned long)((y)[2] & 255)<<8) | \
((unsigned long)((y)[3] & 255)); }
#define STORE64H(x, y) \
{ (y)[0] = (unsigned char)(((x)>>56)&255); (y)[1] = (unsigned char)(((x)>>48)&255); \
(y)[2] = (unsigned char)(((x)>>40)&255); (y)[3] = (unsigned char)(((x)>>32)&255); \
(y)[4] = (unsigned char)(((x)>>24)&255); (y)[5] = (unsigned char)(((x)>>16)&255); \
(y)[6] = (unsigned char)(((x)>>8)&255); (y)[7] = (unsigned char)((x)&255); }
#define LOAD64H(x, y) \
{ x = (((ulong64)((y)[0] & 255))<<56)|(((ulong64)((y)[1] & 255))<<48) | \
(((ulong64)((y)[2] & 255))<<40)|(((ulong64)((y)[3] & 255))<<32) | \
(((ulong64)((y)[4] & 255))<<24)|(((ulong64)((y)[5] & 255))<<16) | \
(((ulong64)((y)[6] & 255))<<8)|(((ulong64)((y)[7] & 255))); }
#endif /* ENDIAN_NEUTRAL */
#ifdef ENDIAN_LITTLE
#define STORE32H(x, y) \
{ (y)[0] = (unsigned char)(((x)>>24)&255); (y)[1] = (unsigned char)(((x)>>16)&255); \
(y)[2] = (unsigned char)(((x)>>8)&255); (y)[3] = (unsigned char)((x)&255); }
#define LOAD32H(x, y) \
{ x = ((unsigned long)((y)[0] & 255)<<24) | \
((unsigned long)((y)[1] & 255)<<16) | \
((unsigned long)((y)[2] & 255)<<8) | \
((unsigned long)((y)[3] & 255)); }
#define STORE64H(x, y) \
{ (y)[0] = (unsigned char)(((x)>>56)&255); (y)[1] = (unsigned char)(((x)>>48)&255); \
(y)[2] = (unsigned char)(((x)>>40)&255); (y)[3] = (unsigned char)(((x)>>32)&255); \
(y)[4] = (unsigned char)(((x)>>24)&255); (y)[5] = (unsigned char)(((x)>>16)&255); \
(y)[6] = (unsigned char)(((x)>>8)&255); (y)[7] = (unsigned char)((x)&255); }
#define LOAD64H(x, y) \
{ x = (((ulong64)((y)[0] & 255))<<56)|(((ulong64)((y)[1] & 255))<<48) | \
(((ulong64)((y)[2] & 255))<<40)|(((ulong64)((y)[3] & 255))<<32) | \
(((ulong64)((y)[4] & 255))<<24)|(((ulong64)((y)[5] & 255))<<16) | \
(((ulong64)((y)[6] & 255))<<8)|(((ulong64)((y)[7] & 255))); }
#ifdef ENDIAN_32BITWORD
#define STORE32L(x, y) \
{ unsigned long __t = (x); memcpy(y, &__t, 4); }
#define LOAD32L(x, y) \
memcpy(&(x), y, 4);
#define STORE64L(x, y) \
{ (y)[7] = (unsigned char)(((x)>>56)&255); (y)[6] = (unsigned char)(((x)>>48)&255); \
(y)[5] = (unsigned char)(((x)>>40)&255); (y)[4] = (unsigned char)(((x)>>32)&255); \
(y)[3] = (unsigned char)(((x)>>24)&255); (y)[2] = (unsigned char)(((x)>>16)&255); \
(y)[1] = (unsigned char)(((x)>>8)&255); (y)[0] = (unsigned char)((x)&255); }
#define LOAD64L(x, y) \
{ x = (((ulong64)((y)[7] & 255))<<56)|(((ulong64)((y)[6] & 255))<<48)| \
(((ulong64)((y)[5] & 255))<<40)|(((ulong64)((y)[4] & 255))<<32)| \
(((ulong64)((y)[3] & 255))<<24)|(((ulong64)((y)[2] & 255))<<16)| \
(((ulong64)((y)[1] & 255))<<8)|(((ulong64)((y)[0] & 255))); }
#else /* 64-bit words then */
#define STORE32L(x, y) \
{ unsigned long __t = (x); memcpy(y, &__t, 4); }
#define LOAD32L(x, y) \
{ memcpy(&(x), y, 4); x &= 0xFFFFFFFF; }
#define STORE64L(x, y) \
{ ulong64 __t = (x); memcpy(y, &__t, 8); }
#define LOAD64L(x, y) \
{ memcpy(&(x), y, 8); }
#endif /* ENDIAN_64BITWORD */
#endif /* ENDIAN_LITTLE */
#ifdef ENDIAN_BIG
#define STORE32L(x, y) \
{ (y)[0] = (unsigned char)(((x)>>24)&255); (y)[1] = (unsigned char)(((x)>>16)&255); \
(y)[2] = (unsigned char)(((x)>>8)&255); (y)[3] = (unsigned char)((x)&255); }
#define LOAD32L(x, y) \
{ x = ((unsigned long)((y)[0] & 255)<<24) | \
((unsigned long)((y)[1] & 255)<<16) | \
((unsigned long)((y)[2] & 255)<<8) | \
((unsigned long)((y)[3] & 255)); }
#define STORE64L(x, y) \
{ (y)[0] = (unsigned char)(((x)>>56)&255); (y)[1] = (unsigned char)(((x)>>48)&255); \
(y)[2] = (unsigned char)(((x)>>40)&255); (y)[3] = (unsigned char)(((x)>>32)&255); \
(y)[4] = (unsigned char)(((x)>>24)&255); (y)[5] = (unsigned char)(((x)>>16)&255); \
(y)[6] = (unsigned char)(((x)>>8)&255); (y)[7] = (unsigned char)((x)&255); }
#define LOAD64L(x, y) \
{ x = (((ulong64)((y)[0] & 255))<<56)|(((ulong64)((y)[1] & 255))<<48) | \
(((ulong64)((y)[2] & 255))<<40)|(((ulong64)((y)[3] & 255))<<32) | \
(((ulong64)((y)[4] & 255))<<24)|(((ulong64)((y)[5] & 255))<<16) | \
(((ulong64)((y)[6] & 255))<<8)|(((ulong64)((y)[7] & 255))); }
#ifdef ENDIAN_32BITWORD
#define STORE32H(x, y) \
{ unsigned long __t = (x); memcpy(y, &__t, 4); }
#define LOAD32H(x, y) \
memcpy(&(x), y, 4);
#define STORE64H(x, y) \
{ (y)[7] = (unsigned char)(((x)>>56)&255); (y)[6] = (unsigned char)(((x)>>48)&255); \
(y)[5] = (unsigned char)(((x)>>40)&255); (y)[4] = (unsigned char)(((x)>>32)&255); \
(y)[3] = (unsigned char)(((x)>>24)&255); (y)[2] = (unsigned char)(((x)>>16)&255); \
(y)[1] = (unsigned char)(((x)>>8)&255); (y)[0] = (unsigned char)((x)&255); }
#define LOAD64H(x, y) \
{ x = (((ulong64)((y)[7] & 255))<<56)|(((ulong64)((y)[6] & 255))<<48)| \
(((ulong64)((y)[5] & 255))<<40)|(((ulong64)((y)[4] & 255))<<32)| \
(((ulong64)((y)[3] & 255))<<24)|(((ulong64)((y)[2] & 255))<<16)| \
(((ulong64)((y)[1] & 255))<<8)|(((ulong64)((y)[0] & 255))); }
#else /* 64-bit words then */
#define STORE32H(x, y) \
{ unsigned long __t = (x); memcpy(y, &__t, 4); }
#define LOAD32H(x, y) \
{ memcpy(&(x), y, 4); x &= 0xFFFFFFFF; }
#define STORE64H(x, y) \
{ ulong64 __t = (x); memcpy(y, &__t, 8); }
#define LOAD64H(x, y) \
{ memcpy(&(x), y, 8); }
#endif /* ENDIAN_64BITWORD */
#endif /* ENDIAN_BIG */
#define BSWAP(x) ( ((x>>24)&0x000000FFUL) | ((x<<24)&0xFF000000UL) | \
((x>>8)&0x0000FF00UL) | ((x<<8)&0x00FF0000UL) )
#ifdef _MSC_VER
/* instrinsic rotate */
#include <stdlib.h>
#pragma intrinsic(_lrotr,_lrotl)
#define ROR(x,n) _lrotr(x,n)
#define ROL(x,n) _lrotl(x,n)
#elif defined(__GNUC__) && defined(__i386__) && !defined(INTEL_CC)
static inline unsigned long ROL(unsigned long word, int i)
{
__asm__("roll %%cl,%0"
:"=r" (word)
:"0" (word),"c" (i));
return word;
}
static inline unsigned long ROR(unsigned long word, int i)
{
__asm__("rorl %%cl,%0"
:"=r" (word)
:"0" (word),"c" (i));
return word;
}
#else
/* rotates the hard way */
#define ROL(x, y) ( (((unsigned long)(x)<<(unsigned long)((y)&31)) | (((unsigned long)(x)&0xFFFFFFFFUL)>>(unsigned long)(32-((y)&31)))) & 0xFFFFFFFFUL)
#define ROR(x, y) ( ((((unsigned long)(x)&0xFFFFFFFFUL)>>(unsigned long)((y)&31)) | ((unsigned long)(x)<<(unsigned long)(32-((y)&31)))) & 0xFFFFFFFFUL)
#endif
#define ROL64(x, y) \
( (((x)<<((ulong64)(y)&63)) | \
(((x)&CONST64(0xFFFFFFFFFFFFFFFF))>>((ulong64)64-((y)&63)))) & CONST64(0xFFFFFFFFFFFFFFFF))
#define ROR64(x, y) \
( ((((x)&CONST64(0xFFFFFFFFFFFFFFFF))>>((ulong64)(y)&CONST64(63))) | \
((x)<<((ulong64)(64-((y)&CONST64(63)))))) & CONST64(0xFFFFFFFFFFFFFFFF))
#undef MAX
#undef MIN
#define MAX(x, y) ( ((x)>(y))?(x):(y) )
#define MIN(x, y) ( ((x)<(y))?(x):(y) )
typedef struct md5_state {
ulong64 length;
ulong32 state[4], curlen;
unsigned char buf[64];
}md5_state;
extern void md5_init(md5_state * md);
extern int md5_process(md5_state * md, const unsigned char *buf, unsigned long len);
extern int md5_done(md5_state * md, unsigned char *hash);
extern int md5_test(void);
#if ARGTYPE == 0
#include <signal.h>
/* this is the default LibTomCrypt macro */
extern void crypt_argchk(char *v, char *s, int d);
#define _ARGCHK(x) if (!(x)) { crypt_argchk(#x, __FILE__, __LINE__); }
#elif ARGTYPE == 1
/* fatal type of error */
#define _ARGCHK(x) assert((x))
#elif ARGTYPE == 2
#define _ARGCHK(x)
#endif
#ifdef __cplusplus
}
#endif
#endif /* CRYPT_H_ */
主函数：
#include "md5.h"
#ifdef MD5
#define F(x,y,z) (z ^ (x & (y ^ z)))
#define G(x,y,z) (y ^ (z & (y ^ x)))
#define H(x,y,z) (x^y^z)
#define I(x,y,z) (y^(x|(~z)))
#define FF(a,b,c,d,M,s,t) \
a = (a + F(b,c,d) + M + t); a = ROL(a, s) + b;
#define GG(a,b,c,d,M,s,t) \
a = (a + G(b,c,d) + M + t); a = ROL(a, s) + b;
#define HH(a,b,c,d,M,s,t) \
a = (a + H(b,c,d) + M + t); a = ROL(a, s) + b;
#define II(a,b,c,d,M,s,t) \
a = (a + I(b,c,d) + M + t); a = ROL(a, s) + b;
#define max 10240
#ifdef SMALL_CODE
static const unsigned char Worder[64] = {
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,
1,6,11,0,5,10,15,4,9,14,3,8,13,2,7,12,
5,8,11,14,1,4,7,10,13,0,3,6,9,12,15,2,
0,7,14,5,12,3,10,1,8,15,6,13,4,11,2,9
};
static const unsigned char Rorder[64] = {
7,12,17,22,7,12,17,22,7,12,17,22,7,12,17,22,
5,9,14,20,5,9,14,20,5,9,14,20,5,9,14,20,
4,11,16,23,4,11,16,23,4,11,16,23,4,11,16,23,
6,10,15,21,6,10,15,21,6,10,15,21,6,10,15,21
};
static const ulong32 Korder[64] = {
0xd76aa478UL, 0xe8c7b756UL, 0x242070dbUL, 0xc1bdceeeUL, 0xf57c0fafUL, 0x4787c62aUL, 0xa8304613UL, 0xfd469501UL,
0x698098d8UL, 0x8b44f7afUL, 0xffff5bb1UL, 0x895cd7beUL, 0x6b901122UL, 0xfd987193UL, 0xa679438eUL, 0x49b40821UL,
0xf61e2562UL, 0xc040b340UL, 0x265e5a51UL, 0xe9b6c7aaUL, 0xd62f105dUL, 0x02441453UL, 0xd8a1e681UL, 0xe7d3fbc8UL,
0x21e1cde6UL, 0xc33707d6UL, 0xf4d50d87UL, 0x455a14edUL, 0xa9e3e905UL, 0xfcefa3f8UL, 0x676f02d9UL, 0x8d2a4c8aUL,
0xfffa3942UL, 0x8771f681UL, 0x6d9d6122UL, 0xfde5380cUL, 0xa4beea44UL, 0x4bdecfa9UL, 0xf6bb4b60UL, 0xbebfbc70UL,
0x289b7ec6UL, 0xeaa127faUL, 0xd4ef3085UL, 0x04881d05UL, 0xd9d4d039UL, 0xe6db99e5UL, 0x1fa27cf8UL, 0xc4ac5665UL,
0xf4292244UL, 0x432aff97UL, 0xab9423a7UL, 0xfc93a039UL, 0x655b59c3UL, 0x8f0ccc92UL, 0xffeff47dUL, 0x85845dd1UL,
0x6fa87e4fUL, 0xfe2ce6e0UL, 0xa3014314UL, 0x4e0811a1UL, 0xf7537e82UL, 0xbd3af235UL, 0x2ad7d2bbUL, 0xeb86d391UL
};
#endif
#include <signal.h>
#if (ARGTYPE == 0)
void crypt_argchk(char *v, char *s, int d)
{
fprintf(stderr, "_ARGCHK '%s' failure on line %d of file %s\n",
v, d, s);
(void)raise(SIGABRT);
}
#endif
void zeromem(void *dst, size_t len)
{
unsigned char *mem = (unsigned char *)dst;
_ARGCHK(dst != NULL);
while (len-- > 0)
*mem++ = 0;
}
void burn_stack(unsigned long len)
{
unsigned char buf[32];
zeromem(buf, sizeof(buf));
if (len > (unsigned long)sizeof(buf))
burn_stack(len - sizeof(buf));
}
/*this function compress 512bits once,and it is called by md5_process and md5_done*/
#ifdef CLEAN_STACK
static void _md5_compress(md5_state *md, unsigned char *buf)
#else
static void md5_compress(md5_state *md, unsigned char *buf)
#endif
{
ulong32 i, W[16], a, b, c, d;
#ifdef SMALL_CODE
ulong32 t;
#endif
/* copy the state into 512-bits into W[0..15] */
for (i = 0; i < 16; i++) {
LOAD32L(W[i], buf + (4*i));
}
/* copy state */
a = md->state[0];
b = md->state[1];
c = md->state[2];
d = md->state[3];
#ifdef SMALL_CODE
for (i = 0; i < 16; ++i) { /*第一轮变换*/
FF(a,b,c,d,W[Worder[i]],Rorder[i],Korder[i]);
t = d; d = c; c = b; b = a; a = t;
}
for (; i < 32; ++i) { /*第二轮变换*/
GG(a,b,c,d,W[Worder[i]],Rorder[i],Korder[i]);
t = d; d = c; c = b; b = a; a = t;
}
for (; i < 48; ++i) { /*第三轮变换*/
HH(a,b,c,d,W[Worder[i]],Rorder[i],Korder[i]);
t = d; d = c; c = b; b = a; a = t;
}
for (; i < 64; ++i) { /*第四轮变换*/
II(a,b,c,d,W[Worder[i]],Rorder[i],Korder[i]);
t = d; d = c; c = b; b = a; a = t;
}
#else
FF(a,b,c,d,W[0],7,0xd76aa478UL) /*第一轮变换开始*/
FF(d,a,b,c,W[1],12,0xe8c7b756UL)
FF(c,d,a,b,W[2],17,0x242070dbUL)
FF(b,c,d,a,W[3],22,0xc1bdceeeUL)
FF(a,b,c,d,W[4],7,0xf57c0fafUL)
FF(d,a,b,c,W[5],12,0x4787c62aUL)
FF(c,d,a,b,W[6],17,0xa8304613UL)
FF(b,c,d,a,W[7],22,0xfd469501UL)
FF(a,b,c,d,W[8],7,0x698098d8UL)
FF(d,a,b,c,W[9],12,0x8b44f7afUL)
FF(c,d,a,b,W[10],17,0xffff5bb1UL)
FF(b,c,d,a,W[11],22,0x895cd7beUL)
FF(a,b,c,d,W[12],7,0x6b901122UL)
FF(d,a,b,c,W[13],12,0xfd987193UL)
FF(c,d,a,b,W[14],17,0xa679438eUL)
FF(b,c,d,a,W[15],22,0x49b40821UL) /*第一轮变换结束*/
GG(a,b,c,d,W[1],5,0xf61e2562UL) /*第二轮变换开始*/
GG(d,a,b,c,W[6],9,0xc040b340UL)
GG(c,d,a,b,W[11],14,0x265e5a51UL)
GG(b,c,d,a,W[0],20,0xe9b6c7aaUL)
GG(a,b,c,d,W[5],5,0xd62f105dUL)
GG(d,a,b,c,W[10],9,0x02441453UL)
GG(c,d,a,b,W[15],14,0xd8a1e681UL)
GG(b,c,d,a,W[4],20,0xe7d3fbc8UL)
GG(a,b,c,d,W[9],5,0x21e1cde6UL)
GG(d,a,b,c,W[14],9,0xc33707d6UL)
GG(c,d,a,b,W[3],14,0xf4d50d87UL)
GG(b,c,d,a,W[8],20,0x455a14edUL)
GG(a,b,c,d,W[13],5,0xa9e3e905UL)
GG(d,a,b,c,W[2],9,0xfcefa3f8UL)
GG(c,d,a,b,W[7],14,0x676f02d9UL)
GG(b,c,d,a,W[12],20,0x8d2a4c8aUL) /*第二轮变换结束*/
HH(a,b,c,d,W[5],4,0xfffa3942UL) /*第三轮变换开始*/
HH(d,a,b,c,W[8],11,0x8771f681UL)
HH(c,d,a,b,W[11],16,0x6d9d6122UL)
HH(b,c,d,a,W[14],23,0xfde5380cUL)
HH(a,b,c,d,W[1],4,0xa4beea44UL)
HH(d,a,b,c,W[4],11,0x4bdecfa9UL)
HH(c,d,a,b,W[7],16,0xf6bb4b60UL)
HH(b,c,d,a,W[10],23,0xbebfbc70UL)
HH(a,b,c,d,W[13],4,0x289b7ec6UL)
HH(d,a,b,c,W[0],11,0xeaa127faUL)
HH(c,d,a,b,W[3],16,0xd4ef3085UL)
HH(b,c,d,a,W[6],23,0x04881d05UL)
HH(a,b,c,d,W[9],4,0xd9d4d039UL)
HH(d,a,b,c,W[12],11,0xe6db99e5UL)
HH(c,d,a,b,W[15],16,0x1fa27cf8UL)
HH(b,c,d,a,W[2],23,0xc4ac5665UL) /*第三轮变换结束*/
II(a,b,c,d,W[0],6,0xf4292244UL) /*第四轮变换开始*/
II(d,a,b,c,W[7],10,0x432aff97UL)
II(c,d,a,b,W[14],15,0xab9423a7UL)
II(b,c,d,a,W[5],21,0xfc93a039UL)
II(a,b,c,d,W[12],6,0x655b59c3UL)
II(d,a,b,c,W[3],10,0x8f0ccc92UL)
II(c,d,a,b,W[10],15,0xffeff47dUL)
II(b,c,d,a,W[1],21,0x85845dd1UL)
II(a,b,c,d,W[8],6,0x6fa87e4fUL)
II(d,a,b,c,W[15],10,0xfe2ce6e0UL)
II(c,d,a,b,W[6],15,0xa3014314UL)
II(b,c,d,a,W[13],21,0x4e0811a1UL)
II(a,b,c,d,W[4],6,0xf7537e82UL)
II(d,a,b,c,W[11],10,0xbd3af235UL)
II(c,d,a,b,W[2],15,0x2ad7d2bbUL)
II(b,c,d,a,W[9],21,0xeb86d391UL) /*第四轮变换结束*/
#endif
md->state[0] = md->state[0] + a;
md->state[1] = md->state[1] + b;
md->state[2] = md->state[2] + c;
md->state[3] = md->state[3] + d;
}
#ifdef CLEAN_STACK
static void md5_compress(md5_state *md, unsigned char *buf)
{
_md5_compress(md, buf);
burn_stack(sizeof(ulong32) * 21);
}
#endif
void md5_init(md5_state * md)
{
_ARGCHK(md != NULL);
/*
md->state[0] = 0x12114567UL; //四个链接变量
md->state[1] = 0x89abcdefUL;
md->state[2] = 0xfedcba98UL;
md->state[3] = 0x76543210UL;
*/
md->state[0] = 0x67452301UL;
md->state[1] = 0xefcdab89UL;
md->state[2] = 0x98badcfeUL;
md->state[3] = 0x10325476UL;
md->curlen = 0;
md->length = 0;
}
/*假设信息的长度为n×512＋l（0<=l<512)。这个函数处理前面的n×512比特，留下的由md5_done函数完成。
*/
int md5_process (md5_state * md, const unsigned char *buf, unsigned long len)
{
unsigned long n;
_ARGCHK(md != NULL);
_ARGCHK(buf != NULL);
if (md->curlen > sizeof(md->buf)) {
return CRYPT_INVALID_ARG;
}
while (len > 0) {
if (md->curlen == 0 && len >= 64) {
md5_compress (md, (unsigned char *)buf);
md->length += 64 * 8;
buf += 64;
len -= 64;
} else {
n = MIN(len, (len - md->curlen));
memcpy(md->buf + md->curlen, buf, (size_t)n);
md->curlen += n;
buf+= n;
len-= n;
if (md->curlen == len) {
md5_compress (md, md->buf);
md->length += 8*len;
md->curlen = 0;
}
}
}
return CRYPT_OK;
}
int md5_done(md5_state * md, unsigned char *hash)
{
int i;
_ARGCHK(md != NULL);
_ARGCHK(hash != NULL);
if (md->curlen >= sizeof(md->buf)) {
return CRYPT_INVALID_ARG;
}
md->length += md->curlen * 8;
/* append the '1' bit */
md->buf[md->curlen++] = (unsigned char)0x80;
/* if the length is currently above 56 bytes we append zeros
* then compress. Then we can fall back to padding zeros and length
* encoding like normal.
*/
if (md->curlen > 56) {
while (md->curlen < 64) {
md->buf[md->curlen++] = (unsigned char)0;
}
md5_compress(md, md->buf);
md->curlen = 0;
}
/* pad upto 56 bytes of zeroes */
while (md->curlen < 56) {
md->buf[md->curlen++] = (unsigned char)0;
}
/* store length */
STORE64L(md->length, md->buf+56);
md5_compress(md, md->buf);
/* copy output */
for (i = 0; i < 4; i++) {
STORE32L(md->state[i], hash+(4*i));
}
#ifdef CLEAN_STACK
zeromem(md, sizeof(md5_state));
#endif
return CRYPT_OK;
}
int md5_test(void)
{
#ifndef LTC_TEST
return CRYPT_NOP;
#else
static const struct {
char *msg;
unsigned char hash[16];
} tests[] = {
{ "",
{ 0xd4, 0x1d, 0x8c, 0xd9, 0x8f, 0x00, 0xb2, 0x04,
0xe9, 0x80, 0x09, 0x98, 0xec, 0xf8, 0x42, 0x7e } },
{ "a",
{0x0c, 0xc1, 0x75, 0xb9, 0xc0, 0xf1, 0xb6, 0xa8,
0x31, 0xc3, 0x99, 0xe2, 0x69, 0x77, 0x26, 0x61 } },
{ "abc",
{ 0x90, 0x01, 0x50, 0x98, 0x3c, 0xd2, 0x4f, 0xb0,
0xd6, 0x96, 0x3f, 0x7d, 0x28, 0xe1, 0x7f, 0x72 } },
{ "message digest",
{ 0xf9, 0x6b, 0x69, 0x7d, 0x7c, 0xb7, 0x93, 0x8d,
0x52, 0x5a, 0x2f, 0x31, 0xaa, 0xf1, 0x61, 0xd0 } },
{ "abcdefghijklmnopqrstuvwxyz",
{ 0xc3, 0xfc, 0xd3, 0xd7, 0x61, 0x92, 0xe4, 0x00,
0x7d, 0xfb, 0x49, 0x6c, 0xca, 0x67, 0xe1, 0x3b } },
{ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
{ 0xd1, 0x74, 0xab, 0x98, 0xd2, 0x77, 0xd9, 0xf5,
0xa5, 0x61, 0x1c, 0x2c, 0x9f, 0x41, 0x9d, 0x9f } },
{ "12345678901234567890123456789012345678901234567890123456789012345678901234567890",
{ 0x57, 0xed, 0xf4, 0xa2, 0x2b, 0xe3, 0xc9, 0x55,
0xac, 0x49, 0xda, 0x2e, 0x21, 0x07, 0xb6, 0x7a } },
{ NULL, { 0 } }
};
int i,j;
unsigned char tmp[16];
md5_state md;
for (i = 0; tests[i].msg != NULL; i++) {
md5_init(&md);
md5_process(&md, (unsigned char *)tests[i].msg, (unsigned long)strlen(tests[i].msg));
md5_done(&md, tmp);
if (memcmp(tmp, tests[i].hash, 16) != 0) {
return CRYPT_FAIL_TESTVECTOR;
}
for(j=0;j<16;j++)
printf("%x",tmp[j]);
printf("\n");
}
return CRYPT_OK;
#endif
}
#endif
void md5(char *mssage)
{
md5_state md;
int i;
unsigned char hash[16];
md5_init(&md);
md5_process(&md,(const unsigned char *)mssage,(unsigned long)strlen(mssage));
md5_done(&md,hash);
printf("哈希值为：");
for(i=0;i<16;i++)
printf("%x",hash[i]);
}
void main()
{
md5_test();
int flag=1,option;
FILE *fp;
char message[max];
while(flag)
{
printf("请选择待处理数据类型[0]字符串,[1]文件:");
scanf("%d",&option);
if (option==0)
{
printf("请输入待处理的字符串: ");
scanf("%s",message);
md5(message);
printf("\n");
}
else if (option==1)
{
char filename[100];
printf("请输入文件名(路径): ");
scanf("%s",filename);
fp=fopen(filename,"r");
if(!fp)
{printf("文件找不到！\n");continue;}
while(!feof(fp))
{
fgets(message,sizeof(message),fp);
}
md5(message);
printf("\n");
}
else
{
flag=0;
}
}
}
运行结果：
小结：
MD5以512位分组来处理输入的信息，且每一分组又被划分为16个32位子分组，经过了一系列的处理后，算法的输出由四个32位分组组成，将这四个32位分组级联后将生成一个128位散列值；
SHA将输入流按照每块512位（64个字节）进行分块，并产生20个字节（160位）的被称为信息认证代码或信息摘要的输出。
MD5加密算法采用的是 小端存储模式，即高位数据放在高地址，低位数据放在低地址。
SHA加密算法采用的是 大端存储模式，即高位数据放在低地址，低位数据放在高地址。