Archive for the ‘C#’ Category

/r/dailyprogrammer – Stream Cipher

Thursday, July 16th, 2015

This time around I thought the stream cipher programming challenge sounded like fun. The program encodes a character string and then decodes it back to the original text using the RC4 method. Below is an example input/output, followed by the code.


class Program
    static void Main(string[] args)
        const int KEY = 31337;
        string message = "High five, bro";

        Console.WriteLine("----Stream Cipher----\n");
        Console.WriteLine("Original Message: " + message + "\n");

        var cipherText = encrypt(message, KEY);
        Console.WriteLine("Cipher Text: " + cipherText + "\n");

        var plainText = decrypt(cipherText, KEY);
        Console.WriteLine("Plain Text: " + plainText);


    static string encrypt( string msg, int key )
        int seed = key;
        int m = 255;
        int a = 124;
        int c = 32;
        byte[] bytes = Encoding.Default.GetBytes(msg);
        var value = ((seed * a) + c) % m;

        for (var b = 0; b < bytes.Length; ++b )
            bytes[b] ^= (byte)value;

        return Encoding.Default.GetString(bytes);

    static string decrypt(string cipher, int key)
        return encrypt(cipher, key);

/r/dailyprogrammer – Poetry in a Haystack

Sunday, July 5th, 2015

I decided to start participating in some of the programming challenges in the dailyprogrammer subreddit. I'm not saying I'm going to do them every day, but maybe one a week; we'll see! The challenge from July 3 is the first one I've attempted. The challenge is to find 3 lines from a famous poem given a text file with 50000 lines in it. Of those 50000 lines, 49997 of them are gibberish. I will be solving the challenges in C# unless otherwise noted. (more…)

MediaNamer – Easily Organize Your TV Shows

Tuesday, February 17th, 2015

Well, I'm not dead, but I have been MIA here for quite some time. Without going into too much detail, the last few months I've been very busy and haven't had as much time for personal projects as I would like. Luckily this last weekend I had some free time and found a problem to solve. (more…)

Subscribe to RSS feed FGS5 Badge