How to create a md5 hash of a string in C?

Question

I\'ve found some md5 code that consists of the following prototypes...

I\'ve been trying to find out where I have to put the string I want to hash, what functions I

Answer 1

Here's a complete example:

#include 
#include 
#include 
#if defined(__APPLE__)
#  define COMMON_DIGEST_FOR_OPENSSL
#  include 
#  define SHA1 CC_SHA1
#else
#  include 
#endif

char *str2md5(const char *str, int length) {
    int n;
    MD5_CTX c;
    unsigned char digest[16];
    char *out = (char*)malloc(33);

    MD5_Init(&c);

    while (length > 0) {
        if (length > 512) {
            MD5_Update(&c, str, 512);
        } else {
            MD5_Update(&c, str, length);
        }
        length -= 512;
        str += 512;
    }

    MD5_Final(digest, &c);

    for (n = 0; n < 16; ++n) {
        snprintf(&(out[n*2]), 16*2, "%02x", (unsigned int)digest[n]);
    }

    return out;
}

    int main(int argc, char **argv) {
        char *output = str2md5("hello", strlen("hello"));
        printf("%s\n", output);
        free(output);
        return 0;
    }