SHA-256算法 C语言实现
感谢 qq_20453319 提醒，现已修正BUG
实现了计算字符串，文件的SHA-256值
算法来自：
Federal.Information.Processing.Standards.Publication.180-2.pdf
下载文档
VS2013下成功编译运行
针对评论区出现的疑问，在这里说明一下：
1.如果出现 _ftelli64未定义 的错误，将_ftelli64替换为ftello64。visual c应该不会有这种错误。
2.函数的第三个参数是计算后的字符串形式，不需要再转换，详情看示例代码。
3.默认计算结果是大写形式，如需小写，将函数中末尾处所有 %08X 替换为 %08x 即可。
/*用法示例*/
#include <stdio.h>
#include <stdlib.h>
extern char* StrSHA256(const char* str, long long length, char* sha256);
int main(void){
char text[] = "blackkitty";
char sha256[65];
StrSHA256(text,sizeof(text)-1,sha256); // sizeof()计算的结果包含了末尾的'\0'应减1
puts(sha256);
puts(StrSHA256(text,sizeof(text)-1,sha256)); // 函数返回值即sha256，直接输出也可以
return 0;
}
使用在线加密验证http://tool.oschina.net/encrypt?type=2
代码如下：
#include <stdio.h>
#include <stdlib.h>
#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))
extern char* StrSHA256(const char* str, long long length, char* sha256){
/*
计算字符串SHA-256
参数说明：
str 字符串指针
length 字符串长度
sha256 用于保存SHA-256的字符串指针
返回值为参数sha256
*/
char *pp, *ppend;
long l, i, W[64], T1, T2, A, B, C, D, E, F, G, H, H0, H1, H2, H3, H4, H5, H6, H7;
H0 = 0x6a09e667, H1 = 0xbb67ae85, H2 = 0x3c6ef372, H3 = 0xa54ff53a;
H4 = 0x510e527f, H5 = 0x9b05688c, H6 = 0x1f83d9ab, H7 = 0x5be0cd19;
long K[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,
};
l = length + ((length % 64 >= 56) ? (128 - length % 64) : (64 - length % 64));
if (!(pp = (char*)malloc((unsigned long)l))) return 0;
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++);
*((long*)(pp + l - 4)) = length << 3;
*((long*)(pp + l - 8)) = length >> 29;
for (ppend = pp + l; pp < ppend; pp += 64){
for (i = 0; i < 16; W[i] = ((long*)pp)[i], i++);
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) + K[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;
}
extern char* FileSHA256(const char* file, char* sha256){
/*
计算文件SHA-256
参数说明：
file 文件路径字符串指针
sha256 用于保存SHA-256的字符串指针
返回值为参数sha256
*/
FILE* fh;
char* addlp, T[64];
long addlsize, j, W[64], T1, T2, A, B, C, D, E, F, G, H, H0, H1, H2, H3, H4, H5, H6, H7;
long long length, i, cpys;
void *pp, *ppend;
H0 = 0x6a09e667, H1 = 0xbb67ae85, H2 = 0x3c6ef372, H3 = 0xa54ff53a;
H4 = 0x510e527f, H5 = 0x9b05688c, H6 = 0x1f83d9ab, H7 = 0x5be0cd19;
long K[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,
};
fh = fopen(file, "rb");
fseek(fh, 0, SEEK_END);
length = _ftelli64(fh);
addlsize = (56 - length % 64 > 0) ? (64) : (128);
if (!(addlp = (char*)malloc(addlsize))) return 0;
cpys = ((length - (56 - length % 64)) > 0) ? (length - length % 64) : (0);
j = (long)(length - cpys);
if (!(pp = (char*)malloc(j))) return 0;
fseek(fh, -j, SEEK_END);
fread(pp, 1, j, fh);
for (i = 0; i < j; addlp[i + 3 - 2 * (i % 4)] = ((char*)pp)[i], i++);
free(pp);
for (addlp[i + 3 - 2 * (i % 4)] = 128, i++; i < addlsize; addlp[i + 3 - 2 * (i % 4)] = 0, i++);
*((long*)(addlp + addlsize - 4)) = length << 3;
*((long*)(addlp + addlsize - 8)) = length >> 29;
for (rewind(fh); 64 == fread(W, 1, 64, fh);){
for (i = 0; i < 64; T[i + 3 - 2 * (i % 4)] = ((char*)W)[i], i++);
for (i = 0; i < 16; W[i] = ((long*)T)[i], i++);
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) + K[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;
}
for (pp = addlp, ppend = addlp + addlsize; pp < ppend; pp = (long*)pp + 16){
for (i = 0; i < 16; W[i] = ((long*)pp)[i], i++);
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) + K[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(addlp); fclose(fh);
sprintf(sha256, "%08X%08X%08X%08X%08X%08X%08X%08X", H0, H1, H2, H3, H4, H5, H6, H7);
return sha256;
}