md5 算法实现（收集网络中好的代码）
//
// Created by natpacket on 2023/8/11.
//
#include "md5.h"
/*
* MD5是一种常见的哈希算法，用于计算消息的摘要值。
* 它将输入消息通过一系列的步骤转化为一个128位（16字节）的哈希值。
* 以下代码实现了MD5的初始化、更新和最终化的函数。
*/
#include <stdio.h>
#include <string.h>
// 算法来源 https://www.cs.cmu.edu/afs/club/usr/jhutz/project/sss/util/md5c.c
/* 常量表 */
static const uint8 PADDING[MD5_BLOCK_SIZE] = {
0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
static const uint32 T[MD5_BLOCK_SIZE] = {
0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05,
0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,
0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
};
/* 左移位数 */
#define SHIFT(a, b) ((a << b) | (a >> (32 - b)))
/* FF, GG, HH, II函数 */
#define FF(a, b, c, d, x, s, ac) { \
(a) += F((b), (c), (d)) + (x) + (uint32)(ac); \
(a) = SHIFT((a), (s)); \
(a) += (b); \
}
#define GG(a, b, c, d, x, s, ac) { \
(a) += G((b), (c), (d)) + (x) + (uint32)(ac); \
(a) = SHIFT((a), (s)); \
(a) += (b); \
}
#define HH(a, b, c, d, x, s, ac) { \
(a) += H((b), (c), (d)) + (x) + (uint32)(ac); \
(a) = SHIFT((a), (s)); \
(a) += (b); \
}
#define II(a, b, c, d, x, s, ac) { \
(a) += I((b), (c), (d)) + (x) + (uint32)(ac); \
(a) = SHIFT((a), (s)); \
(a) += (b); \
}
/* F, G, H, I函数 */
#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)))
/* 编码函数 高地址往低地址复制数据*/
void Encode(uint8 *output, const uint32 *input, uint32 len) {
uint32 i, j;
for (i = 0, j = 0; j < len; i++, j += 4) {
output[j] = (uint8)(input[i] & 0xff);
output[j + 1] = (uint8)((input[i] >> 8) & 0xff);
output[j + 2] = (uint8)((input[i] >> 16) & 0xff);
output[j + 3] = (uint8)((input[i] >> 24) & 0xff);
}
}
/* 解码函数 高地址往低地址复制数据*/
void Decode(uint32 *output, const uint8 *input, uint32 len) {
uint32 i, j;
for (i = 0, j = 0; j < len; i++, j += 4)
output[i] = ((uint32)input[j]) | (((uint32)input[j + 1]) << 8) |
(((uint32)input[j + 2]) << 16) | (((uint32)input[j + 3]) << 24);
}
/* 初始化MD5算法上下文 */
void MD5_Init(MD5_CTX *context) {
context->count[0] = context->count[1] = 0;
context->state[0] = 0x67452301;
context->state[1] = 0xefcdab89;
context->state[2] = 0x98badcfe;
context->state[3] = 0x10325476;
}
/* 转换函数 */
void MD5_Transform(uint32 state[4], const uint8 block[MD5_BLOCK_SIZE]) {
uint32 a = state[0];
uint32 b = state[1];
uint32 c = state[2];
uint32 d = state[3];
uint32 x[16];
// Decode(x, block, MD5_BLOCK_SIZE);
memcpy(x, block, MD5_BLOCK_SIZE);
FF(a, b, c, d, x[0], 7, T[0]);
FF(d, a, b, c, x[1], 12, T[1]);
FF(c, d, a, b, x[2], 17, T[2]);
FF(b, c, d, a, x[3], 22, T[3]);
FF(a, b, c, d, x[4], 7, T[4]);
FF(d, a, b, c, x[5], 12, T[5]);
FF(c, d, a, b, x[6], 17, T[6]);
FF(b, c, d, a, x[7], 22, T[7]);
FF(a, b, c, d, x[8], 7, T[8]);
FF(d, a, b, c, x[9], 12, T[9]);
FF(c, d, a, b, x[10], 17, T[10]);
FF(b, c, d, a, x[11], 22, T[11]);
FF(a, b, c, d, x[12], 7, T[12]);
FF(d, a, b, c, x[13], 12, T[13]);
FF(c, d, a, b, x[14], 17, T[14]);
FF(b, c, d, a, x[15], 22, T[15]);
GG(a, b, c, d, x[1], 5, T[16]);
GG(d, a, b, c, x[6], 9, T[17]);
GG(c, d, a, b, x[11], 14, T[18]);
GG(b, c, d, a, x[0], 20, T[19]);
GG(a, b, c, d, x[5], 5, T[20]);
GG(d, a, b, c, x[10], 9, T[21]);
GG(c, d, a, b, x[15], 14, T[22]);
GG(b, c, d, a, x[4], 20, T[23]);
GG(a, b, c, d, x[9], 5, T[24]);
GG(d, a, b, c, x[14], 9, T[25]);
GG(c, d, a, b, x[3], 14, T[26]);
GG(b, c, d, a, x[8], 20, T[27]);
GG(a, b, c, d, x[13], 5, T[28]);
GG(d, a, b, c, x[2], 9, T[29]);
GG(c, d, a, b, x[7], 14, T[30]);
GG(b, c, d, a, x[12], 20, T[31]);
HH(a, b, c, d, x[5], 4, T[32]);
HH(d, a, b, c, x[8], 11, T[33]);
HH(c, d, a, b, x[11], 16, T[34]);
HH(b, c, d, a, x[14], 23, T[35]);
HH(a, b, c, d, x[1], 4, T[36]);
HH(d, a, b, c, x[4], 11, T[37]);
HH(c, d, a, b, x[7], 16, T[38]);
HH(b, c, d, a, x[10], 23, T[39]);
HH(a, b, c, d, x[13], 4, T[40]);
HH(d, a, b, c, x[0], 11, T[41]);
HH(c, d, a, b, x[3], 16, T[42]);
HH(b, c, d, a, x[6], 23, T[43]);
HH(a, b, c, d, x[9], 4, T[44]);
HH(d, a, b, c, x[12], 11, T[45]);
HH(c, d, a, b, x[15], 16, T[46]);
HH(b, c, d, a, x[2], 23, T[47]);
II(a, b, c, d, x[0], 6, T[48]);
II(d, a, b, c, x[7], 10, T[49]);
II(c, d, a, b, x[14], 15, T[50]);
II(b, c, d, a, x[5], 21, T[51]);
II(a, b, c, d, x[12], 6, T[52]);
II(d, a, b, c, x[3], 10, T[53]);
II(c, d, a, b, x[10], 15, T[54]);
II(b, c, d, a, x[1], 21, T[55]);
II(a, b, c, d, x[8], 6, T[56]);
II(d, a, b, c, x[15], 10, T[57]);
II(c, d, a, b, x[6], 15, T[58]);
II(b, c, d, a, x[13], 21, T[59]);
II(a, b, c, d, x[4], 6, T[60]);
II(d, a, b, c, x[11], 10, T[61]);
II(c, d, a, b, x[2], 15, T[62]);
II(b, c, d, a, x[9], 21, T[63]);
state[0] += a;
state[1] += b;
state[2] += c;
state[3] += d;
}
/* 更新MD5算法上下文 */
void MD5_Update(MD5_CTX *context, const uint8 *input, uint32 inputlen) {
uint32 i, index, partlen;
// 计算缓冲区中剩余空间
// context->count[0] >> 3 (bit位数 变 byte字节数)
// 0x3f == 63
// count & 63 == count % 63 (求余)
// 当前记录的位数进行求余 表示缓冲区待处理的数据长度
index = (context->count[0] >> 3) & 0x3F;
// 更新位计数器
// 如果位计数器溢出，则更新高位计数器
// 比如 下面的情况
// unsigned int a= 0xffffffff;
// printf("%x \n",a+3); 打印为: 2
if ((context->count[0] += (inputlen << 3)) < (inputlen << 3))
context->count[1]++;
context->count[1] += (inputlen >> 29);
// 计算处理后的数据长度
partlen = MD5_BLOCK_SIZE - index;
// 处理第一部分数据
if (inputlen >= partlen) {
memcpy(&context->buffer[index], input, partlen);
MD5_Transform(context->state, context->buffer);
// 处理剩余的数据块
for (i = partlen; i + MD5_BLOCK_SIZE <= inputlen; i += MD5_BLOCK_SIZE)
MD5_Transform(context->state, &input[i]);
index = 0;
} else {
i = 0;
}
// 缓冲区中留下的数据
memcpy(&context->buffer[index], &input[i], inputlen - i);
}
/* 结束MD5算法，生成摘要结果 */
void MD5_Final(MD5_CTX *context, uint8 digest[16]) {
uint8 bits[8];
uint32 index, padlen;
// Encode(bits, context->count, 8);
memcpy(bits, context->count, 8);
index = (context->count[0] >> 3) & 0x3F;
//计算需要填充的长度
padlen = (index < 56) ? (56 - index) : (120 - index);
// 数据填充
MD5_Update(context, PADDING, padlen);
// 填充长度
MD5_Update(context, bits, 8);
// Encode(digest, context->state, MD5_DIGEST_SIZE);
memcpy(digest, context->state, MD5_DIGEST_SIZE);
memset(context, 0, sizeof(*context));
}
/* 计算字符串的MD5摘要 */
void MD5(const uint8 *input, uint32 inputlen, uint8 output[MD5_DIGEST_SIZE]) {
MD5_CTX context;
MD5_Init(&context);
MD5_Update(&context, input, inputlen);
MD5_Final(&context, output);
}
/* 测试代码 */
void testmd5() {
uint8 input[] = "qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq";
uint8 output[MD5_DIGEST_SIZE];
MD5(input, strlen((char *)input), output);
printf("%s MD5: ",input);
for (uint32 i = 0; i < MD5_DIGEST_SIZE; i++) {
printf("%02x", output[i]);
}
printf("\n");
// unsigned int a= 0xffffffff;
// printf("%x \n",a+3);
// int b=3;
// if( (a += 3) < b)
// printf(" < \n");
// int a =0x67452301;
// int c = 0;
// uint8 b[4] ={0};
// memcpy(b, &a, 4);
// for (uint32 i = 0; i < 4; i++) {
// printf("%02x", b[i]);
// }
// printf("\n");
// Encode(b, reinterpret_cast<const uint32 *>(&a), 4);
// for (uint32 i = 0; i < 4; i++) {
// printf("%02x", b[i]);
// }
// printf("\n");
// Decode(reinterpret_cast<uint32 *>(&c), b, 4);
// printf("%x",c);
// printf("\n");
// memcpy(&c, b, 4);
// printf("%x",c);
// printf("\n");
}
//
// Created by natpacket on 2023/8/11.
//
#ifndef ARITHMETIC_MD5_H
#define ARITHMETIC_MD5_H
#define MD5_BLOCK_SIZE 64
#define MD5_DIGEST_SIZE 16
typedef unsigned char uint8; // 8位无符号整数类型
typedef unsigned int uint32; // 32位无符号整数类型
/* MD5算法上下文结构 */
typedef struct {
uint32 state[4]; // 维护MD5算法的运算状态
uint32 count[2]; // 记录消息的位数
uint8 buffer[MD5_BLOCK_SIZE]; // 缓存消息块
} MD5_CTX;
void MD5_Init(MD5_CTX *context);
void MD5_Update(MD5_CTX *context, const uint8 *input, uint32 inputlen);
void MD5_Final(MD5_CTX *context, uint8 digest[16]);
void MD5(const uint8 *input, uint32 inputlen, uint8 output[MD5_DIGEST_SIZE]);
void testmd5();
#endif //ARITHMETIC_MD5_H
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