md5 encoding example

md5.c

#include <stdio.h>
#include <string.h>
#include <openssl/md5.h>

#define u_char unsigned char

int main(int argc, const char *argv[])
{
    u_char hashb[64], hasht[128], *text = hasht;
    MD5_CTX md5;
    const static u_char hex[] = "0123456789abcdef";
    const u_char *input = "helloworld";

    memset(hashb, 0, 64);
    memset(hasht, 0, 128);
    MD5_Init(&md5);
    MD5_Update(&md5, input, strlen(input));
    MD5_Final(hashb, &md5);

    // translated to more readable format
    int i = 0;
    for(; i < 16; i++){
        *text++ = hex[hashb[i] >> 4];
        *text++ = hex[hashb[i] & 0xf];
    }

    *text = '\0';

    printf("input: %s\n", input );
    printf("output: %s\n", hasht);

    /*
     * same as below...
    u_char md[17];
    memset(md, 0, 17);
    MD5(input, strlen(input), md);
    printf("MD5() output: ");
    for(i = 0; i < 16; i++){
        printf("%2x ", md[i]);
    }
    printf("\n");
    */
    return 0;
}