c语言实现sha1加密代码，不使用openssl

SHA-1（安全散列算法1）是一种密码散列函数，产生一个160位（20字节）的散列值，用于确保信息传输完整一致。在C语言中实现SHA-1加密不使用外部库如OpenSSL，可以通过直接实现SHA-1算法来完成。下面是一个简化的SHA-1加密算法的C语言实现示例：

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>

// 定义四个辅助函数
#define SHABLK0(i) (W[i] = data[i<<2] ^ data[(i<<2)+1] ^ data[(i<<2)+2] ^ data[(i<<2)+3])
#define SHABLK(i) (W[i&15] ^ W[(i-3)&15])
#define循环左移(n,x)  (((x) << (n)) | ((x) >> (32-(n))))
#define CH(x,y,z) ((x & y) ^ (~x & z))
#define PARITY(x,y,z) ((x ^ y) ^ z)
#define Maj(x,y,z) ((x & y) ^ (x & z) ^ (y & z))

// SHA-1 初始化
void SHA1Init(uint32_t* state) {
    state[0] = 0x67452301;
    state[1] = 0xefcdab89;
    state[2] = 0x98badcfe;
    state[3] = 0x10325476;
    state[4] = 0xc3d2e1f0;
}

// SHA-1 迭代处理
void SHA1Transform(uint32_t state[5], const uint8_t buffer[64]) {
    uint32_t W[16], a, b, c, d, e;
    int i;
    for (i = 0; i < 16; i++)
        W[i] = ((uint32_t)buffer[4*i]) << 24 | ((uint32_t)buffer[4*i+1]) << 16 |
               ((uint32_t)buffer[4*i+2]) << 8 | ((uint32_t)buffer[4*i+3]);
    for (i = 16; i < 80; i++)
        W[i] =循环左移(1, W[i-3] ^ W[i-8] ^ W[i-14] ^ W[i-16]);
    a = state[0];
    b = state[1];
    c = state[2];
    d = state[3];
    e = state[4];
    for (i = 0; i < 20; i++) {
        e +=循环左移(5, a) + CH(b, c, d) + 0x5a827999 + W[i];
        b =循环左移(30, b);
    }
    for (i = 20; i < 40; i++) {
        e +=循环左移(5, a) + PARITY(b, c, d) + 0x6ed9eba1 + W[i];
        b =循环左移(30, b);
    }
    for (i = 40; i < 60; i++) {
        e +=循环左移(5, a) + Maj(b, c, d) + 0x8f1bbcdc + W[i];
        b =循环左移(30, b);
    }
    for (i = 60; i < 80; i++) {
        e +=循环左移(5, a) + PARITY(b, c, d) + 0xca62c1d6 + W[i];
        b =循环左移(30, b);
    }
    state[0] += a;
    state[1] += b;
    state[2] += c;
    state[3] += d;
    state[4] += e;
}

// SHA-1 加密处理
void SHA1Update(uint32_t state[5], const uint8_t* buffer, uint32_t count) {
    uint32_t data[16];
    int i;
    for (i = 0; i < count; i++) {
        data[i>>2] = (buffer[i] << 24) | ((uint32_t)buffer[i+1] << 16) |
                     ((uint32_t)buffer[i+2] << 8) | (buffer[i+3]);
        if ((i & 63) == 63) {
            SHA1Transform(state, data);
            data[0] = 0;
            data[1] = 0;
            data[2] = 0;
            data[3] = 0;
            data[14] = 0;
            data[15] = 0;
        }
    }
}

// SHA-1 最终处理和输出
void SHA1Final(uint8_t digest[20], uint32_t state[5]) {
    uint32_t data[16];
    uint32_t count = 0;
    int i;
    data[14] = count>>29 | (count << 3);
    data[15] = count << 3;
    for (i = 0; i < 14; i++) {
        data[i>>2] = (digest[i] << 24) | ((uint32_t)digest[i+1] << 16) |
                     ((uint32_t)digest[i+2] << 8) | (digest[i+3]);
    }
    SHA1Transform(state, data);
    for (i = 0; i < 20; i++)
        digest[i] = (state[i>>2] >> ((3-(i & 3)) * 8)) & 0xff;
}

int main() {
    // 示例使用
    uint8_t digest[20];
    uint32_t state[5];
    char input[] = "The quick brown fox jumps over the lazy dog";
    
    SHA1Init(state);
    SHA1Update(state, (uint8_t*)input, strlen(input));
    SHA1Final(digest, state);

    for (int i = 0; i < 20; i++)
        printf("%02x", digest[i]);
    printf("\n");
    return 0;
}

上述代码展示了如何使用C语言实现SHA-1加密，其中包含了SHA-1算法的核心步骤。这只是一个简化版的实现，不包含输入数据的填充和分块处理，实际使用时需要根据需要进行适当的调整和补充。