bitcoin_miner.cpp

#include <iostream>
#include <iomanip>
#include <sstream>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <openssl/sha.h>
#include <unistd.h> // for sleep
using namespace std;

vector<char> hexToBytes(const string& hex) {
  vector<char> bytes;

  for (unsigned int i = 0; i < hex.length(); i += 2) {
    string byteString = hex.substr(i, 2);
    char byte = (char) strtol(byteString.c_str(), NULL, 16);
    bytes.push_back(byte);
  }

  return bytes;
}

string sha256(const string str)
{
//    unsigned int SHA256_DIGEST_LENGTH = 256;
    unsigned char hash[SHA256_DIGEST_LENGTH];
    SHA256_CTX sha256;
    SHA256_Init(&sha256);
    SHA256_Update(&sha256, str.c_str(), str.size());
    SHA256_Final(hash, &sha256);
    stringstream ss;
    for(int i = 0; i < SHA256_DIGEST_LENGTH; i++)
    {
        ss << hex << setw(2) << setfill('0') << (int)hash[i];
    }
    return ss.str();
}

string sha256(const vector<char> inputBuf)
{
//    unsigned int SHA256_DIGEST_LENGTH = 256;
    unsigned char hash[SHA256_DIGEST_LENGTH];
    SHA256_CTX sha256;
    SHA256_Init(&sha256);
    SHA256_Update(&sha256, inputBuf.data(), inputBuf.size());
    SHA256_Final(hash, &sha256);
    stringstream ss;
    for(int i = 0; i < SHA256_DIGEST_LENGTH; i++)
    {
        ss << hex << setw(2) << setfill('0') << (int)hash[i];
    }
    return ss.str();
}

int main() {
    string input = "0100000081cd02ab7e569e8bcd9317e2fe99f2de44d49ab2b8851ba4a308000000000000e320b6c2fffc8d750423db8b1eb942ae710e951ed797f7affc8892b0f1fc122bc7f5d74df2b9441a42a14695";

    while(true) {
        cout << sha256(hexToBytes(input)) << endl;
        cout << sha256(hexToBytes(sha256(hexToBytes(input)))) << endl;
        usleep(1000000);
    }

    return 0;
}

todo: split out nonce, date, etc. and have iterating logic

Notes

• need sudo apt-get install libssl-dev for openssl/sha.h