给我一段Hash256的标准C语言源代码

### 回答1：
下面是一段 Hash256 的 C 语言源代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/sha.h>

int main(int argc, char *argv[])
{
unsigned char hash[SHA256_DIGEST_LENGTH];
const char *input = "Hello, world!";

SHA256((unsigned char*)input, strlen(input), hash);

for (int i = 0; i < SHA256_DIGEST_LENGTH; i++)
printf("%02x", hash[i]);
printf("\n");

return 0;
}

这段代码使用了 OpenSSL 库中的 SHA256 函数来对输入的字符串 "Hello, world!" 进行哈希。最后输出的是十六进制编码的哈希值。

### 回答2：
以下是使用标准C语言的Hash256算法的源代码：

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

#define ROTLEFT(x, c) (((x) << (c)) | ((x) >> (32 - (c))))

#define SHA256_BLOCK_SIZE 32

typedef struct {
    uint8_t data[64];
    uint32_t datalen;
    unsigned long long bitlen;
    uint32_t state[8];
} SHA256_CTX;

const uint32_t 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
};

void sha256_transform(SHA256_CTX *ctx, const uint8_t data[]) {
    uint32_t a, b, c, d, e, f, g, h, i, j, t1, t2, m[64];

    for (i = 0, j = 0; i < 16; ++i, j += 4)
        m[i] = (data[j] << 24) | (data[j + 1] << 16) | (data[j + 2] << 8) | (data[j + 3]);
    for (; i < 64; ++i)
        m[i] = (ROTLEFT(m[i - 2], 17) ^ ROTLEFT(m[i - 2], 19) ^ (m[i - 2] >> 10)) + m[i - 7] +
               (ROTLEFT(m[i - 15], 7) ^ ROTLEFT(m[i - 15], 18) ^ (m[i - 15] >> 3)) + m[i - 16];

    a = ctx->state[0];
    b = ctx->state[1];
    c = ctx->state[2];
    d = ctx->state[3];
    e = ctx->state[4];
    f = ctx->state[5];
    g = ctx->state[6];
    h = ctx->state[7];

    for (i = 0; i < 64; ++i) {
        t1 = h + (ROTLEFT(e, 6) ^ ROTLEFT(e, 11) ^ ROTLEFT(e, 25)) + ((e & f) ^ (~e & g)) + k[i] + m[i];
        t2 = (ROTLEFT(a, 2) ^ ROTLEFT(a, 13) ^ ROTLEFT(a, 22)) + ((a & b) ^ (a & c) ^ (b & c));
        h = g;
        g = f;
        f = e;
        e = d + t1;
        d = c;
        c = b;
        b = a;
        a = t1 + t2;
    }

    ctx->state[0] += a;
    ctx->state[1] += b;
    ctx->state[2] += c;
    ctx->state[3] += d;
    ctx->state[4] += e;
    ctx->state[5] += f;
    ctx->state[6] += g;
    ctx->state[7] += h;
}

void sha256_init(SHA256_CTX *ctx) {
    ctx->datalen = 0;
    ctx->bitlen = 0;
    ctx->state[0] = 0x6a09e667;
    ctx->state[1] = 0xbb67ae85;
    ctx->state[2] = 0x3c6ef372;
    ctx->state[3] = 0xa54ff53a;
    ctx->state[4] = 0x510e527f;
    ctx->state[5] = 0x9b05688c;
    ctx->state[6] = 0x1f83d9ab;
    ctx->state[7] = 0x5be0cd19;
}

void sha256_update(SHA256_CTX *ctx, const uint8_t data[], uint32_t len) {
    uint32_t i;

    for (i = 0; i < len; ++i) {
        ctx->data[ctx->datalen] = data[i];
        ctx->datalen++;
        if (ctx->datalen == 64) {
            sha256_transform(ctx, ctx->data);
            ctx->bitlen += 512;
            ctx->datalen = 0;
        }
    }
}

void sha256_final(SHA256_CTX *ctx, uint8_t hash[]) {
    uint32_t i;

    i = ctx->datalen;

    if (ctx->datalen < 56) {
        ctx->data[i++] = 0x80;
        while (i < 56)
            ctx->data[i++] = 0x00;
    } else {
        ctx->data[i++] = 0x80;
        while (i < 64)
            ctx->data[i++] = 0x00;
        sha256_transform(ctx, ctx->data);
        memset(ctx->data, 0, 56);
    }

    ctx->bitlen += ctx->datalen * 8;
    ctx->data[63] = ctx->bitlen;
    ctx->data[62] = ctx->bitlen >> 8;
    ctx->data[61] = ctx->bitlen >> 16;
    ctx->data[60] = ctx->bitlen >> 24;
    ctx->data[59] = ctx->bitlen >> 32;
    ctx->data[58] = ctx->bitlen >> 40;
    ctx->data[57] = ctx->bitlen >> 48;
    ctx->data[56] = ctx->bitlen >> 56;
    sha256_transform(ctx, ctx->data);

    for (i = 0; i < 4; ++i) {
        hash[i] = (ctx->state[0] >> (24 - i * 8)) & 0x000000ff;
        hash[i + 4] = (ctx->state[1] >> (24 - i * 8)) & 0x000000ff;
        hash[i + 8] = (ctx->state[2] >> (24 - i * 8)) & 0x000000ff;
        hash[i + 12] = (ctx->state[3] >> (24 - i * 8)) & 0x000000ff;
        hash[i + 16] = (ctx->state[4] >> (24 - i * 8)) & 0x000000ff;
        hash[i + 20] = (ctx->state[5] >> (24 - i * 8)) & 0x000000ff;
        hash[i + 24] = (ctx->state[6] >> (24 - i * 8)) & 0x000000ff;
        hash[i + 28] = (ctx->state[7] >> (24 - i * 8)) & 0x000000ff;
    }
}

int main() {
    char str[] = "Hello World";
    uint8_t hash[SHA256_BLOCK_SIZE];
    SHA256_CTX ctx;

    sha256_init(&ctx);
    sha256_update(&ctx, (uint8_t *)str, strlen(str));
    sha256_final(&ctx, hash);

    printf("Hash: ");
    for (int i = 0; i < SHA256_BLOCK_SIZE; i++) {
        printf("%02x", hash[i]);
    }
    printf("\n");

    return 0;
}

该源代码使用SHA-256算法实现了Hash256的功能。它包含了SHA256_CTX结构体用于保存中间状态和结果，以及定义了SHA256的各种操作函数，如sha256_transform、sha256_update和sha256_final等。在main函数中，通过传入待哈希的字符串，调用这些函数对其进行SHA-256哈希计算，最后打印出计算得到的哈希值。

### 回答3：
Hash256是一种常用的哈希函数，它能够将任意长度的输入数据转化为固定长度的哈希值。以下是一段标准的C语言源代码实现：

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

#define ROTL(x, n) (((x) << (n)) | ((x) >> (32 - (n))))

void sha256(const uint8_t *message, uint32_t len, uint8_t hash[32]) {
    uint32_t 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
    };

    uint32_t h[8] = {
        0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
    };

    uint32_t w[64];
    uint32_t a, b, c, d, e, f, g, h, i, j, t1, t2;

    for (i = 0; i < len / 64; i++) {
        memcpy(w, message + i * 64, 64);

        for (j = 16; j < 64; j++) {
            w[j] = w[j-16] + ROTL(w[j-15], 7) + w[j-7] + ROTL(w[j-2], 15);
        }

        a = h[0];
        b = h[1];
        c = h[2];
        d = h[3];
        e = h[4];
        f = h[5];
        g = h[6];
        h = h[7];

        for (j = 0; j < 64; j++) {
            t1 = h + SIGMA1(e) + CH(e, f, g) + k[j] + w[j];
            t2 = SIGMA0(a) + MAJ(a, b, c);
            h = g;
            g = f;
            f = e;
            e = d + t1;
            d = c;
            c = b;
            b = a;
            a = t1 + t2;
        }

        h[0] += a;
        h[1] += b;
        h[2] += c;
        h[3] += d;
        h[4] += e;
        h[5] += f;
        h[6] += g;
        h[7] += h;
    }

    memcpy(hash, h, 32);
}

int main() {
    uint8_t message[] = "Hello, World!";
    uint8_t hash[32];

    sha256(message, sizeof(message) - 1, hash);

    printf("Hash: ");
    for (int i = 0; i < 32; i++) {
        printf("%02x", hash[i]);
    }
    printf("\n");

    return 0;
}

上述代码实现了对消息进行SHA-256哈希运算，并打印出哈希结果。可以根据需要将message数组替换为其他输入数据的数组，并在main函数中进行调用。