如何哈希两次字符串 C openssl

Question

我的目标是用 sha256 对一个字符串进行两次哈希处理，但我没有得到很好的结果这是代码：

void double_hash(char *string, char output[65]) {
    unsigned char out[32];
    char hash[65];
    unsigned char scnd_hash[65];
    SHA256_CTX sha256;
    SHA256_Init(&sha256);
    SHA256_Update(&sha256, string, strlen(string));
    SHA256_Final(out, &sha256);
    for (int i = 0; i < SHA256_DIGEST_LENGTH; i++) {
        sprintf(hash + (i * 2), "%02x", out[i]);
    }
    SHA256_CTX sha256_2;
    SHA256_Init(&sha256_2);
    SHA256_Update(&sha256_2, hash, strlen(hash));
    SHA256_Final(scnd_hash, &sha256_2);
    for (int i = 0; i < SHA256_DIGEST_LENGTH; i++) {
        sprintf(output + (i * 2), "%02x", scnd_hash[i]);
    }
}

对于字符串“hello”，它的作用是：

hello
2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824
d7914fe546b684688bb95f4f888a92dfc680603a75f23eb823658031fff766d9

但我想要:

hello
2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824
9595c9df90075148eb06860365df33584b75bff782a510c6cd4883a419833d50

我试过这段代码，但没有产生好的结果：

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

void double_hash(char *string, char output[65]) {
    unsigned char out[32];
    unsigned char scnd_hash[65];
    SHA256_CTX sha256;
    SHA256_Init(&sha256);
    SHA256_Update(&sha256, string, strlen(string));
    SHA256_Final(out, &sha256);
    SHA256_CTX sha256_2;
    SHA256_Init(&sha256_2);
    SHA256_Update(&sha256_2, out, strlen((char *)out));
    SHA256_Final(scnd_hash, &sha256_2);
    for (int i = 0; i < SHA256_DIGEST_LENGTH; i++) {
        sprintf(output + (i * 2), "%02x", scnd_hash[i]);
    }
}

int main() {
    char outp[65];
    char *hello = "hello";
    double_hash(hello, outp);
    printf("%s", outp);
}

它产生 852d59ce6fb3099c9d563870d298f0108eff079e1dde63e66c68d2e0b40353c1

谢谢

Answer 1

要以 9595c9df9007... 结束，对 32 字节二进制数据执行第二次哈希，而不是对 字符串。

// SHA256_Update(&sha256_2, hash, strlen(hash));
SHA256_Update(&sha256_2, out, 32);

参考：SHA256

如何哈希两次字符串 C openssl

How to hash twice a string C openssl

c

hash

openssl

sha256