Ok, I admit that I don't know of an "official" name for this algorithm.
I did hear that it is the same method as what a scytale employs.
Basically, if you are given the encrypted text, you start at a given letter
and then count N letters (wrapping around from the end to the beginning)
forward to the next letter. It can be used for the third part of the
Kryptos statue. I can also
pre-load the K3
information for you.
If you do use this for decoding the Kryptos, you will see that you need
to just count every 192nd letter. Additionally, I have made 5
characters lowercase: The "s" and the "l" are the first two characters, in
case you wanted to count by hand. The "y", "a", and "r" are the three
letters that are offset from the rest of the text.
Spaces are NOT ignored and will be moved around appropriately as though
they were letters. Newlines (enters / returns) will be ignored.
This is your encoded or decoded text.