【安全算法之SHA1】SHA1摘要运算的C语言源码实现
- 概述
- 头文件定义
- C语言版本的实现源码
- 测试用例
- github仓库
- 更多参考链接
概述
大家都知道摘要算法在安全领域，也是一个特别重要的存在，而SHA1是其中比较常见的一种摘要算法，它的特点就是计算复杂度较低，不等长的数据原文输入，可以得出等长的摘要值，这个值是固定为20字节。正是由于这种特殊性，很多重要的数据完整性校验领域，都可以看到SHA1的影子。
今天给大家带来SHA1的C源码版本实现，欢迎大家深入学习和讨论。
头文件定义
头文件定义如下，主要定义了SHA1的上下文结构体，以及导出的三个API：
#ifndef __SHA1_H__
#define __SHA1_H__
#include
#define SHA1_DIGEST_LEN 20 // SHA1 outputs a 20 byte digest
typedef struct _sha1_ctx_t {
uint32_t total[2]; /*!< number of bytes processed */
uint32_t state[5]; /*!< intermediate digest state */
uint8_t buffer[64]; /*!< data block being processed */
} sha1_ctx_t;
void crypto_sha1_init(sha1_ctx_t *ctx);
void crypto_sha1_update(sha1_ctx_t *ctx, const uint8_t *data, uint32_t len);
void crypto_sha1_final(sha1_ctx_t *ctx, uint8_t *digest);
#endif // __SHA1_H__
C语言版本的实现源码
下面是SHA1的C语言版本实现，主要也是围绕导出的3个API：
#include
#include "sha1.h"
/*
* 32-bit integer manipulation macros (big endian)
*/
#ifndef GET_UINT32_BE
#define GET_UINT32_BE(n, b, i) \
{ \
(n) = ((uint32_t)(b)[(i)] << 24) | ((uint32_t)(b)[(i) + 1] << 16) | \
((uint32_t)(b)[(i) + 2] << 8) | ((uint32_t)(b)[(i) + 3]); \
}
#endif
#ifndef PUT_UINT32_BE
#define PUT_UINT32_BE(n, b, i) \
{ \
(b)[(i)] = (uint8_t)((n) >> 24); \
(b)[(i) + 1] = (uint8_t)((n) >> 16); \
(b)[(i) + 2] = (uint8_t)((n) >> 8); \
(b)[(i) + 3] = (uint8_t)((n)); \
}
#endif
static const uint8_t sha1_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
};
static void local_sha1_process(sha1_ctx_t *ctx,
const uint8_t data[64])
{
uint32_t temp, W[16], A, B, C, D, E;
GET_UINT32_BE(W[0], data, 0);
GET_UINT32_BE(W[1], data, 4);
GET_UINT32_BE(W[2], data, 8);
GET_UINT32_BE(W[3], data, 12);
GET_UINT32_BE(W[4], data, 16);
GET_UINT32_BE(W[5], data, 20);
GET_UINT32_BE(W[6], data, 24);
GET_UINT32_BE(W[7], data, 28);
GET_UINT32_BE(W[8], data, 32);
GET_UINT32_BE(W[9], data, 36);
GET_UINT32_BE(W[10], data, 40);
GET_UINT32_BE(W[11], data, 44);
GET_UINT32_BE(W[12], data, 48);
GET_UINT32_BE(W[13], data, 52);
GET_UINT32_BE(W[14], data, 56);
GET_UINT32_BE(W[15], data, 60);
#define S(x, n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))
#define R(t) \
(temp = W[(t - 3) & 0x0F] ^ W[(t - 8) & 0x0F] ^ W[(t - 14) & 0x0F] ^ \
W[t & 0x0F], \
(W[t & 0x0F] = S(temp, 1)))
#define P(a, b, c, d, e, x) \
{ \
e += S(a, 5) + F(b, c, d) + K + x; \
b = S(b, 30); \
}
A = ctx->state[0];
B = ctx->state[1];
C = ctx->state[2];
D = ctx->state[3];
E = ctx->state[4];
#define F(x, y, z) (z ^ (x & (y ^ z)))
#define K 0x5A827999
P(A, B, C, D, E, W[0]);
P(E, A, B, C, D, W[1]);
P(D, E, A, B, C, W[2]);
P(C, D, E, A, B, W[3]);
P(B, C, D, E, A, W[4]);
P(A, B, C, D, E, W[5]);
P(E, A, B, C, D, W[6]);
P(D, E, A, B, C, W[7]);
P(C, D, E, A, B, W[8]);
P(B, C, D, E, A, W[9]);
P(A, B, C, D, E, W[10]);
P(E, A, B, C, D, W[11]);
P(D, E, A, B, C, W[12]);
P(C, D, E, A, B, W[13]);
P(B, C, D, E, A, W[14]);
P(A, B, C, D, E, W[15]);
P(E, A, B, C, D, R(16));
P(D, E, A, B, C, R(17));
P(C, D, E, A, B, R(18));
P(B, C, D, E, A, R(19));
#undef K
#undef F
#define F(x, y, z) (x ^ y ^ z)
#define K 0x6ED9EBA1
P(A, B, C, D, E, R(20));
P(E, A, B, C, D, R(21));
P(D, E, A, B, C, R(22));
P(C, D, E, A, B, R(23));
P(B, C, D, E, A, R(24));
P(A, B, C, D, E, R(25));
P(E, A, B, C, D, R(26));
P(D, E, A, B, C, R(27));
P(C, D, E, A, B, R(28));
P(B, C, D, E, A, R(29));
P(A, B, C, D, E, R(30));
P(E, A, B, C, D, R(31));
P(D, E, A, B, C, R(32));
P(C, D, E, A, B, R(33));
P(B, C, D, E, A, R(34));
P(A, B, C, D, E, R(35));
P(E, A, B, C, D, R(36));
P(D, E, A, B, C, R(37));
P(C, D, E, A, B, R(38));
P(B, C, D, E, A, R(39));
#undef K
#undef F
#define F(x, y, z) ((x & y) | (z & (x | y)))
#define K 0x8F1BBCDC
P(A, B, C, D, E, R(40));
P(E, A, B, C, D, R(41));
P(D, E, A, B, C, R(42));
P(C, D, E, A, B, R(43));
P(B, C, D, E, A, R(44));
P(A, B, C, D, E, R(45));
P(E, A, B, C, D, R(46));
P(D, E, A, B, C, R(47));
P(C, D, E, A, B, R(48));
P(B, C, D, E, A, R(49));
P(A, B, C, D, E, R(50));
P(E, A, B, C, D, R(51));
P(D, E, A, B, C, R(52));
P(C, D, E, A, B, R(53));
P(B, C, D, E, A, R(54));
P(A, B, C, D, E, R(55));
P(E, A, B, C, D, R(56));
P(D, E, A, B, C, R(57));
P(C, D, E, A, B, R(58));
P(B, C, D, E, A, R(59));
#undef K
#undef F
#define F(x, y, z) (x ^ y ^ z)
#define K 0xCA62C1D6
P(A, B, C, D, E, R(60));
P(E, A, B, C, D, R(61));
P(D, E, A, B, C, R(62));
P(C, D, E, A, B, R(63));
P(B, C, D, E, A, R(64));
P(A, B, C, D, E, R(65));
P(E, A, B, C, D, R(66));
P(D, E, A, B, C, R(67));
P(C, D, E, A, B, R(68));
P(B, C, D, E, A, R(69));
P(A, B, C, D, E, R(70));
P(E, A, B, C, D, R(71));
P(D, E, A, B, C, R(72));
P(C, D, E, A, B, R(73));
P(B, C, D, E, A, R(74));
P(A, B, C, D, E, R(75));
P(E, A, B, C, D, R(76));
P(D, E, A, B, C, R(77));
P(C, D, E, A, B, R(78));
P(B, C, D, E, A, R(79));
#undef K
#undef F
ctx->state[0] += A;
ctx->state[1] += B;
ctx->state[2] += C;
ctx->state[3] += D;
ctx->state[4] += E;
}
/*
* SHA-1 process init
*/
void crypto_sha1_init(sha1_ctx_t *ctx)
{
memset(ctx, 0, sizeof(sha1_ctx_t));
ctx->total[0] = 0;
ctx->total[1] = 0;
ctx->state[0] = 0x67452301;
ctx->state[1] = 0xEFCDAB89;
ctx->state[2] = 0x98BADCFE;
ctx->state[3] = 0x10325476;
ctx->state[4] = 0xC3D2E1F0;
}
/*
* SHA-1 process buffer
*/
void crypto_sha1_update(sha1_ctx_t *ctx, const uint8_t *input,
uint32_t ilen)
{
uint32_t fill;
uint32_t left;
if (ilen == 0) {
return;
}
left = ctx->total[0] & 0x3F;
fill = 64 - left;
ctx->total[0] += (uint32_t)ilen;
ctx->total[0] &= 0xFFFFFFFF;
if (ctx->total[0] < (uint32_t)ilen) {
ctx->total[1]++;
}
if (left && ilen >= fill) {
memcpy((void *)(ctx->buffer + left), input, fill);
local_sha1_process(ctx, ctx->buffer);
input += fill;
ilen -= fill;
left = 0;
}
while (ilen >= 64) {
local_sha1_process(ctx, input);
input += 64;
ilen -= 64;
}
if (ilen > 0) {
memcpy((void *)(ctx->buffer + left), input, ilen);
}
}
/*
* SHA-1 final digest
*/
void crypto_sha1_final(sha1_ctx_t *ctx, uint8_t *digest)
{
uint32_t last, padn;
uint32_t high, low;
uint8_t msglen[8];
high = (ctx->total[0] >> 29) | (ctx->total[1] << 3);
low = (ctx->total[0] << 3);
PUT_UINT32_BE(high, msglen, 0);
PUT_UINT32_BE(low, msglen, 4);
last = ctx->total[0] & 0x3F;
padn = (last < 56) ? (56 - last) : (120 - last);
crypto_sha1_update(ctx, sha1_padding, padn);
crypto_sha1_update(ctx, msglen, 8);
PUT_UINT32_BE(ctx->state[0], digest, 0);
PUT_UINT32_BE(ctx->state[1], digest, 4);
PUT_UINT32_BE(ctx->state[2], digest, 8);
PUT_UINT32_BE(ctx->state[3], digest, 12);
PUT_UINT32_BE(ctx->state[4], digest, 16);
}
测试用例
针对SHA1导出的三个接口，我编写了以下测试用例：
#include
#include
#include "sha1.h"
#include "convert.h"
int log_hexdump(const char *title, const unsigned char *data, int len)
{
char str[160], octet[10];
int ofs, i, k, d;
const unsigned char *buf = (const unsigned char *)data;
const char dimm[] = "+------------------------------------------------------------------------------+";
printf("%s (%d bytes):\r\n", title, len);
printf("%s\r\n", dimm);
printf("| Offset : 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 0123456789ABCDEF |\r\n");
printf("%s\r\n", dimm);
for (ofs = 0; ofs < (int)len; ofs += 16) {
d = snprintf( str, sizeof(str), "| %08X: ", ofs );
for (i = 0; i < 16; i++) {
if ((i + ofs) < (int)len) {
snprintf( octet, sizeof(octet), "%02X ", buf[ofs + i] );
} else {
snprintf( octet, sizeof(octet), " " );
}
d += snprintf( &str[d], sizeof(str) - d, "%s", octet );
}
d += snprintf( &str[d], sizeof(str) - d, " " );
k = d;
for (i = 0; i < 16; i++) {
if ((i + ofs) < (int)len) {
str[k++] = (0x20 <= (buf[ofs + i]) && (buf[ofs + i]) <= 0x7E) ? buf[ofs + i] : '.';
} else {
str[k++] = ' ';
}
}
str[k] = '\0';
printf("%s |\r\n", str);
}
printf("%s\r\n", dimm);
return 0;
}
int main(int argc, const char *argv[])
{
const char *data = "C1D0F8FB4958670DBA40AB1F3752EF0D";
const char *digest_exp_str = "B36BFDB04A31F6C55E0D592B8F2D3219FBC2424D";
uint8_t digest_calc[SHA1_DIGEST_LEN];
uint8_t digest_exp_hex[SHA1_DIGEST_LEN];
sha1_ctx_t ctx;
const char *p_calc = data;
uint8_t data_bytes[128];
uint16_t len_bytes;
char data_str[128];
if (argc > 1) {
p_calc = argv[1];
}
utils_hex_string_2_bytes(data, data_bytes, &len_bytes);
log_hexdump("data_bytes", data_bytes, len_bytes);
utils_bytes_2_hex_string(data_bytes, len_bytes, data_str);
printf("data_str: %s\n", data_str);
if (!strcmp(data, data_str)) {
printf("hex string - bytes convert OK\n");
} else {
printf("hex string - bytes convert FAIL\n");
}
crypto_sha1_init(&ctx);
crypto_sha1_update(&ctx, (uint8_t *)p_calc, strlen(p_calc));
crypto_sha1_final(&ctx, digest_calc);
utils_hex_string_2_bytes(digest_exp_str, digest_exp_hex, &len_bytes);
if (len_bytes == sizeof(digest_calc) && !memcmp(digest_calc, digest_exp_hex, sizeof(digest_calc))) {
printf("SHA1 digest test OK\n");
log_hexdump("digest_calc", digest_calc, sizeof(digest_calc));
} else {
log_hexdump("digest_calc", digest_calc, sizeof(digest_calc));
log_hexdump("digest_exp", digest_exp_hex, sizeof(digest_exp_hex));
printf("SHA1 digest test FAIL\n");
}
return 0;
}
测试用例比较简单，就是对字符串C1D0F8FB4958670DBA40AB1F3752EF0D进行SHA1运算，期望的摘要结果的hexstring是B36BFDB04A31F6C55E0D592B8F2D3219FBC2424D，这个期望值是用算法工具算出来的。
先用API接口算出摘要值，再与期望值比较，这里有个hexstringtobyte的转换，如果比较一致则表示API计算OK；反之，接口计算失败。
同时，也欢迎大家设计提供更多的测试案例代码。
github仓库
以上代码和测试用例，及编译运行等，可以参考我的github仓库，有详细的流程介绍，欢迎大家交流讨论。如果有帮助到你的话，记得帮忙点亮一颗星哦。
更多参考链接
[1] 【安全算法的github仓库】
[2] 【安全算法之概述】一文带你简要了解常见常用的安全算法
审核编辑 黄昊宇