Hint

05 - Bools for fools
Calculate this!

((not(a) and b) or c) xor d

boolsforfools_fixed.zip

Approach

The hint is pretty obvious that you need to do some boolean operations on the attached files. To start, I load the text and get rid of all of the whitespace, so I am just dealing with the 1s and 0s. I then wrote functions for each of the operatoins (not, and, or, and xor)

Here is the not implementation as an example. See the full source on GitHub

public static string Not(string input)
{
    var result = new StringBuilder();
    foreach (var s in input)
    {
        Validate(s);
        if (s == '1')
        {
            result.Append("0");
        }
        else if (s == '0')
        {
            result.Append("1");
        }
        else
        {
            throw new Exception();
        }
    }

    return result.ToString();
}

Once I had all of that wired up, I ended up with the result of:

1111111000100110001111111
1000001011100011001000001
1011101010000010101011101
1011101001001010001011101
1011101011101100101011101
1000001010101101001000001
1111111010101010101111111
0000000010110011100000000
1101001100011100001110110
0111110011011000111101001
0000101010011100110101001
0011010111111101110111010
1101011000110101111101010
0100100101010100111001011
1001001010010110100010101
0100010011010110000101001
1111111100101101111110101
0000000010001010100010101
1111111011111111101011111
1000001001001010100010110
1011101001001110111110010
1011101010110101000110000
1011101000101111000011001
1000001011011100010100000
1111111010100001100000111

I tried various encodings and translations on this data, until we got a hint from CodeMashCTF:

Now it is obvious that this represents a QR code. I wrote a little code to write data to an image:

public static string Format(string input)
{
    var bmp = new System.Drawing.Bitmap(25, 25);
    var g = System.Drawing.Graphics.FromImage(bmp);
    var whitepen = new Pen(Brushes.White);
    var blackpen = new Pen(Brushes.Black);
    var row = 0;
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < input.Length; i++)
    {
        if (i % 25 == 0 && i != 0)
        {
            row++;
            sb.Append("\r\n");
        }
        sb.Append(input[i] == '1' ? "1" : "0");
        var pen = input[i] == '1' ? blackpen : whitepen;
        g.DrawRectangle(pen, i % 25, row, 1, 1);
    }
    bmp.Save("D:\\temp\\cm\\qr.bmp");
    g.Dispose();
    bmp.Dispose();
    return sb.ToString();
}

The output image looks like this:

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