/*
 * gcc $(pkg-config --cflags --libs openssl) -o proof proof.c
 */
#include <stdio.h>
#include <openssl/sha.h>
#include <openssl/bio.h>
#include <openssl/evp.h>

int main(int argc, char **argv) {
    const char *target = "\x86\xf7\xa2\x8c";
    long data = 0;
    unsigned char hash[20];
    do {
        ++data;
        SHA1((char *) &data, sizeof(data), hash);
    } while (memcmp(target, hash, 4) != 0);
    
    BIO *bio, *b64;
    b64 = BIO_new(BIO_f_base64());
    bio = BIO_new_fp(stdout, BIO_NOCLOSE);
    bio = BIO_push(b64, bio);
    BIO_write(bio, (char *) &data, sizeof(data));
    BIO_flush(bio);
    BIO_free_all(bio);
    return 0;
}