sha256.h

#ifndef SHA256_HASH
#define SHA256_HASH

#include <iostream>
#include <iomanip>
#include <sstream>
#include <string>

using namespace std;

#include <openssl/sha.h>

string sha256( const string &str ){

    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();

}


/*

sudo apt-get install libssl-dev
g++ -lcrypto main.cc


int main() {
    cout << sha256("1234567890_1") << endl;
    cout << sha256("1234567890_2") << endl;
    cout << sha256("1234567890_3") << endl;
    cout << sha256("1234567890_4") << endl;
    return 0;
}
*/


#endif