MD5源代码分析、供大家学习
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// shiyan.cpp : 定义控制台应用程序的入口点。
//#include "stdafx.h"
#include <stdio.h>
#include <time.h>
#include <string.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
#ifndef PROTOTYPES
#define PROTOTYPES 0
#endif
/* PROTO_LIST is defined depending on how PROTOTYPES is defined above.
If using PROTOTYPES, then PROTO_LIST returns the list, otherwise it
returns an empty list.*/
#if PROTOTYPES
#define PROTO_LIST(list) list
#else
#define PROTO_LIST(list) ()
#endif
/* 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); \
}
#define MD_CTX MD5_CTX
#define MDInit MD5Init
#define MD5Update MD5Update
#define MDFinal MD5Final
/* Length of test block, number of test blocks.*/
#define TEST_BLOCK_LEN 10000
#define TEST_BLOCK_COUNT 10000
/* POINTER defines a generic pointer type */
typedef unsigned char *POINTER;
/* UINT2 defines a two byte word */
typedef unsigned short int UINT2;
/* UINT4 defines a four byte word */
typedef unsigned long int UINT4;
/* 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 *));
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
};
/* MD5 initialization. Begins an MD5 operation, writing a new context.*/
void MD5Init (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;
}
/* Note: Replace "for loop" with standard memcpy if possible.*/
static void MD5_memcpy (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 (POINTER output,int value,unsigned int len)
{
unsigned int i;
for (i = 0; i < len; i++)
((char *)output)[i] = (char)value;
}
/* Decodes input (unsigned char) into output (UINT4). Assumes len isa multiple of 4.*/
static void Decode (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);
}
/* MD5 basic transformation. Transforms state based on block.*/
static void MD5Transform (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));
}
/* MD5 block update operation. Continues an MD5 message-digest
operation, processing another message block, and updating the
context.*/
void MD5Update (MD5_CTX *context,unsigned char *input,unsigned int inputLen)
{
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);
}
/* Encodes input (UINT4) into output (unsigned char). Assumes len is a multiple of 4.*/
static void Encode (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);
}
}
/* MD5 finalization. Ends an MD5 message-digest operation, writing the
the message digest and zeroizing the context.*/
void MD5Final (unsigned char digest[16], MD5_CTX *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));
}
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]));
/* Main driver.*/
/* Prints a message digest in hexadecimal.*/
static void MDPrint (unsigned char digest[16])
{
unsigned int i;
for (i = 0; i < 16; i++)
printf ("%02x", digest[i]);
}
/* Digests a string and prints the result. */
static void MDString (char *string)
{
MD5_CTX context;
unsigned char digest[16];
unsigned int len = strlen (string);
MD5Init (&context);
MD5Update (&context,(unsigned char*)string,len);
MD5Final (digest, &context);
printf ("MD5 (\"%s\") = ",string);
MDPrint (digest);
printf ("\n");
}
/* Measures the time to digest TEST_BLOCK_COUNT TEST_BLOCK_LEN-byte blocks.*/
static void MDTimeTrial ()
{
MD5_CTX context;
time_t endTime, startTime;
unsigned char block[TEST_BLOCK_LEN], digest[16];
unsigned int i;
printf("MD5 time trial. Digesting %d %d-byte blocks ...", 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 */
MD5Init (&context);
for (i = 0; i<TEST_BLOCK_COUNT; i++)
MD5Update (&context, block, TEST_BLOCK_LEN);
MD5Final (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 ("MD5 test suite:\n");
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 (char *filename)
{
FILE *file;
MD5_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 {
MD5Init (&context);
while (len = fread (buffer, 1, 1024, file))
MD5Update (&context, buffer, len);
MD5Final (digest, &context);
fclose (file);
printf ("MD5 (%s) = ",filename);
MDPrint (digest);
printf ("\n");
}
}
/* Digests the standard input and prints the result.*/
static void MDFilter ()
{
MD5_CTX context;
int len;
unsigned char buffer[16], digest[16];
MD5Init (&context);
while(len = fread (buffer, 1, 16, stdin)<16)
MD5Update (&context, buffer, len);
MD5Final (digest, &context);
MDPrint (digest);
printf ("\n");
}
int menu(){ //菜单选择
int i;
printf("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@\n");
printf("@@ 【1】digests string @@\n");
printf("@@ 【2】runs time trial @@\n");
printf("@@ 【3】runs test script @@\n");
printf("@@ 【4】digests file @@\n");
printf("@@ 【5】digests standard input @@\n");
printf("@@ 【0】退出 @@\n");
printf("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@\n");
printf("请选择0~6操作:\n");
for(;;){
scanf("%d",&i);
if(i<0||i>5)
printf("选择错误，请重新选择操作，O(∩_∩)O~：\n");
else
break;
}
return i;
}
void main(){
while(1){
switch(menu()){
case 1:
char str[1024];
printf("请输入字符串：");
scanf("%s",str);
MDString(str);
break;
case 2:
MDTimeTrial ();
break;
case 3:
MDTestSuite ();
break;
case 4:
char str1[128];
printf("请输入文件路径及文件名：");
scanf("%s",str1);
MDFile(str1);
break;
case 5:
MDFilter ();
break;
case 0:
return;
}
}
}
（龙铭洪）
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