【安全算法之SHA1】SHA1摘要运算的C语言源码实现-摘要算法作用

【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：

复制 #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：

复制 #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：

复制 #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。