C语言实现 SHA256算法

最新推荐文章于 2024-03-08 16:01:14 发布

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这篇博客详细介绍了如何使用C语言实现SHA256哈希算法，包括定义了一系列的位操作宏，如ROTL和SR，以及用于计算过程的函数。文章通过具体的步骤展示了如何将输入字符串转换为SHA256哈希值，并提供了相应的关键代码片段。

#define SHA256_ROTL(a,b) (((a>>(32-b))&(0x7fffffff>>(31-b)))|(a<<b))
#define SHA256_SR(a,b) ((a>>b)&(0x7fffffff>>(b-1)))
#define SHA256_Ch(x,y,z) ((x&y)^((~x)&z))
#define SHA256_Maj(x,y,z) ((x&y)^(x&z)(y&z))
#define SHA256_E0(x) (SHA256_ROTL(x,30)^{SHA256_ROTL(x,19)}SHA256_ROTL(x,10))
#define SHA256_E1(x) (SHA256_ROTL(x,26)^{SHA256_ROTL(x,21)}SHA256_ROTL(x,7))
#define SHA256_O0(x) (SHA256_ROTL(x,25)^{SHA256_ROTL(x,14)}SHA256_SR(x,3))
#define SHA256_O1(x) (SHA256_ROTL(x,15)^{SHA256_ROTL(x,13)}SHA256_SR(x,10))

void StrSHA256(const unsigned char* str, uint32_t length, unsigned char* sha256)
{
unsigned char *pp, *ppend;
unsigned char q[256];
static uint32_t l, i, W[64], T1, T2, A, B, C, D, E, F, G, H, H0, H1, H2, H3, H4, H5, H6, H7;
uint32_t Key[64] = {
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
};

H0 = 0x6a09e667, H1 = 0xbb67ae85, H2 = 0x3c6ef372, H3 = 0xa54ff53a;
H4 = 0x510e527f, H5 = 0x9b05688c, H6 = 0x1f83d9ab, H7 = 0x5be0cd19;

l = length + ((length % 64 >= 56) ? (128 - length % 64) : (64 - length % 64));
if (!(pp = (&q))) ;
for (i = 0; i < length; pp[i + 3 - 2 * (i % 4)] = str[i], i++);
for (pp[i + 3 - 2 * (i % 4)] = 128, i++; i < l; pp[i + 3 - 2 * (i % 4)] = 0, i++);
*((uint8_t*)(pp + l - 4)) = length << 3;
*((uint8_t*)(pp + l - 8)) = length >> 29;
for (ppend = pp + l; pp < ppend; pp += 64)
{
    //for (i = 0; i < 16; W[i] = ((uint32_t*)pp)[i], i++);
    for (i = 0; i < 16; i++)
    {
        W[i] = ((uint32_t)pp[i*4+3]<< 24) + ((uint32_t)pp[i*4+2]<< 16) + ((uint32_t)pp[i*4+1]<< 8 ) + ((uint32_t)pp[i*4]);
    }
    
    for (i = 16; i < 64; W[i] = (SHA256_O1(W[i - 2]) + W[i - 7] + SHA256_O0(W[i - 15]) + W[i - 16]), i++);
    A = H0, B = H1, C = H2, D = H3, E = H4, F = H5, G = H6, H = H7;
    for (i = 0; i < 64; i++)
    {
        T1 = H + SHA256_E1(E) + SHA256_Ch(E, F, G) + Key[i] + W[i];
        T2 = SHA256_E0(A) + SHA256_Maj(A, B, C);
        H = G, G = F, F = E, E = D + T1, D = C, C = B, B = A, A = T1 + T2;
    }
    H0 += A, H1 += B, H2 += C, H3 += D, H4 += E, H5 += F, H6 += G, H7 += H;
}
//free(pp - l);
sprintf(sha256, "%08X%08X%08X%08X%08X%08X%08X%08X", H0, H1, H2, H3, H4, H5, H6, H7);
//return sha256;

}

unsigned char strnumb0[14];
在这里插入图片描述