Fun & Cryptos

[Nullable]

@Infamous:
There are no "elegant" solutions anyway, but it could be narrowed down even more, you just need the first 8 bytes and a few assumptions for it to work.
@Ultimation:
Yes, of course the code could've been optimized, but it wasn't intended to be efficient or even practical.

[Ultimation]

#Bump 1st Keygen ME added.

Originally Posted by Nullable

@Infamous:
There are no "elegant" solutions anyway, but it could be narrowed down even more, you just need the first 8 bytes and a few assumptions for it to work.
@Ultimation:
Yes, of course the code could've been optimized, but it wasn't intended to be efficient or even practical.

Lets see if you can work your way through Keygen Me 1

[_DreadNought_]

Next please.

 Spoiler

        static void Main(string[] args)
        {
            Console.WriteLine("Enter your name:");
            string name = Console.ReadLine();
            string key = "INVALIDSERIAL";
            string serial = "";
            for(int i =0;i < name.Length;i++)
            {
                byte b = (byte) name[i];
                b ^= (byte) key[i%key.Length];
                string p1 = b.ToString("X2");
                string p2 = ((byte) b ^ name.Length).ToString("X2");
                serial += p1 + p2 + '-';
            }
            serial = serial.Substring(0, serial.Length - 1);
            Console.WriteLine("Your serial:"+serial);
            Console.Read();
        }

[Ultimation]

#bump Keygen me #2 added

no one ?

[InfamousNoone]

I don't have the time to attempt it right now. Too stressed, lol.

[Nullable]

I'll give it a try when I get enough free time on my hands. **** them finals..

[_DreadNought_]

Noone else cracked number two yet?
#bump

[soeey]

What is it,What does it mean?

[CptSky]

Originally Posted by _DreadNought_

Noone else cracked number two yet?
#bump

Checked rapidly through Olly with CrossOver (before it crashed ). Found probably the validation routine. But, I'm too busy to really check more. Maybe at some point.

Btw, would you like to crack one if I do one in C++ ? Could help me to make it harder to crack ? (I haven't done it in C++ yet, but the base is in C#)

[Ultimation]

yep, go for it

[phize]

My solution to Keygenme #2 (haven't tried #1, just assumed #2 was harder)

 Spoiler

#include <windows.h>
#include <iostream>
#include <sstream>
#include <string>
#include <iomanip>

std::string GetHardDiskSerial(const std::string& driveLetter)
{
    DWORD serialNumber;
    GetVolumeInformation(driveLetter.c_str(), NULL, 522, &serialNumber, NULL, NULL, NULL, 0);

    std::stringstream ss;
    ss << std::hex << std::uppercase << serialNumber;
    return ss.str();
}

std::string GenerateSerialNumber(const std::string& hardDiskSerial, const std::string& userName)
{
    std::string hddSerial(1, 0);
    hddSerial.append(hardDiskSerial);

    const int nameLength = userName.length();
    const int serialLength = hardDiskSerial.length();

    std::ostringstream oss;
    for (int i = 0; i < userName.length(); ++i)
    {
        int index = (i + 1) % serialLength;
        int ch = userName[i] ^ hddSerial[index];

        oss << std::uppercase << std::hex << std::setfill('0') << std::setw(2) << ch;
        ch ^= nameLength;
        oss << ch << (i == nameLength - 1 ? "" : "-");
    }
    return oss.str();
}

int main(int argc, char* argv[])
{
    std::cout << GenerateSerialNumber(GetHardDiskSerial("C:\\"), "phize"); // 4441-5E5B-595C-3E3B-5752

    return 0;
}

[_DreadNought_]

Originally Posted by phize

My solution to Keygenme #2 (haven't tried #1, just assumed #2 was harder)

 Spoiler

#include <windows.h>
#include <iostream>
#include <sstream>
#include <string>
#include <iomanip>

std::string GetHardDiskSerial(const std::string& driveLetter)
{
    DWORD serialNumber;
    GetVolumeInformation(driveLetter.c_str(), NULL, 522, &serialNumber, NULL, NULL, NULL, 0);

    std::stringstream ss;
    ss << std::hex << std::uppercase << serialNumber;
    return ss.str();
}

std::string GenerateSerialNumber(const std::string& hardDiskSerial, const std::string& userName)
{
    std::string hddSerial(1, 0);
    hddSerial.append(hardDiskSerial);

    const int nameLength = userName.length();
    const int serialLength = hardDiskSerial.length();

    std::ostringstream oss;
    for (int i = 0; i < userName.length(); ++i)
    {
        int index = (i + 1) % serialLength;
        int ch = userName[i] ^ hddSerial[index];

        oss << std::uppercase << std::hex << std::setfill('0') << std::setw(2) << ch;
        ch ^= nameLength;
        oss << ch << (i == nameLength - 1 ? "" : "-");
    }
    return oss.str();
}

int main(int argc, char* argv[])
{
    std::cout << GenerateSerialNumber(GetHardDiskSerial("C:\\"), "phize"); // 4441-5E5B-595C-3E3B-5752

    return 0;
}

Not that I'm doubting you, Can you post a screenshot that it works?

On a side note, Try this one.

Rules: All the rules that Ultimation has for his Crackme's + NO Reflector, It's NOT protected, But using reflector makes it too easy try it without.

 Spoiler

If you use reflector for it, you suck

[phize]

Originally Posted by _DreadNought_

Not that I'm doubting you, Can you post a screenshot that it works?

 Spoiler

It doesn't take input from the console though, but that's easy to add

[Ultimation]

Very nice work, here is comes my 3rd one

#bump Keygenme 3 added