Recursive nested algorithm - c++

Question

I am trying to create an algorithm for bruteForce cracking MD5 hash.
My goal is to measure the time consumption when splitting into fibers for the processor and optionally graphics in compute clastr.
I got stuck in creating an algorithm.
The input should be a string. According to the number of string characters, I need to create the same number of forcycles.
Statically written for 3 digist, it looks like this:
#include <iostream>
#include <string>
#include "md5.h"
using namespace std;
int main()
{
string imput = "slv";
cout << "imput string: "<< imput << endl;
cout << "MD5 HASH: "<< wantedHash << endl;
do
{
cout << '\n' << "Enable BruteForce Craker";
} while (cin.get() != '\n');
string s;
for(int i=0; i != 256; i++)
{
for(int j=0; j != 256; j++)
{
for(int k=0; k != 256; k++)
{
string s = md5(string(1,(char)i) + string(1,(char)j) + string(1,(char)k));
serchCounter++;
if(s == wantedHash)
{
cout << "Find: " << string(1,(char)i) + string(1,(char)j) + string(1,(char)k) << endl;
cout << "Count TestedHash: " << serchCounter << endl;
return 0;
}
}
}
}
return 0;
}
My idea .. something like that ...
#include <iostream>
#include <string>
#include "md5.h"
using namespace std;
string imput = "s";
string wantedHash = md5(imput);
double serchCounter = 0;
int bruteForse(int longString, string s)
{
for(int i=0; i != 256; i++)
{
string s = md5(string(1,(char)i));
serchCounter++;
if(s == wantedHash)
{
cout << "Find: " << string(1,(char)i);
cout << "Count TestedHash: " << serchCounter << endl;
return 0;
}
}
if(longString > 1) bruteForse(--longString, s);
return 0;
}
int main()
{
cout << "imput string: "<< imput << endl;
cout << "MD5 HASH: "<< wantedHash << endl;
bruteForse(imput.length(),imput);
}

Answer 1

I would do:
bool increase(std::string& s)
{
for (auto rit = s.rbegin(); rit != s.rend(); ++rit) {
auto& c = s[i];
if (c == -1) {
c = 0;
continue;
} else if (c == 127) {
c = -128;
} else {
++c;
}
return true;
}
return false;
}
void bruteForce(std::size_t size, const string& wantedHash)
{
std::string s;
s.resize(size);
do {
if (md5(s) == wantedHash) {
cout << "Find: " << s << std::endl;
}
} while (increase(s));
}