www.mikescher.com/www/statics/euler/Euler_Problem-059_explanation.md

This task had a lot of Befunge specific problems, but first let's look at the solving strategy:

• We go through all 26^3 passwords and test look if they generate illegal characters (smaller 32 or bigger 127).
• We also see if one of the first twelve characters is a space, assuming the first word is no longer than twelve characters.
• The leaves us with around one-hundred viable passwords.
• We use the fact that in the English language the letter e is pretty common and take the password with the highest count of e.
• The rest is just decrypting the text and counting the values.

Now to our Befunge specific problems:

• First we need to input the raw data. Our best call is inserting the data directly into the program and then parsing it in the first step into an array.
• The next problem is the missing xor operator. To perform an xor operation we need to go through all bits and xor them individually (a xor b == (a+b) % 2). This is an extremely pricey operation. And to speed this up we generate an complete 128x128 xor look up-table with all possible xor operations.

All in all a not really optimal problem for Befunge but still a fun challenge