So here´s this bathroom with that pixelated design “GitHub contributions style”.

Because of a comment I made the other day someone asked me the other how could this wall possibly contain a hidden, encoded message. Lets do a little digging into it.

A way to decode this wall would be to consider a base 3 or ternary base, by doing:

– white pixel = 0
– light green pixel = 1
– dark green pixel = 2

And now read the code. For example, starting on the upper corner from left to right you get the sequence:

120000 011110 201011 0110012 … and so on until all the wall is covered.

Now you have a code that a machine can process.

Next steps would be:
– Translate that into ASCII to see if you are lucky
– Read top-down instead of left-right and try again.
– The message in ASCII could be encrypted with another layer, and requires further analysis.

But the best strategy would be first of all to run an information entropy analysis on the file (Shannon entropy). A high-entropy file indicates that a file is either encrypted, compressed, or just contains truly random bytes.