1st pass encryption - MIF.CLGMFELCMLM.
2nd pass encryption - VO.IOSTSKQOPYY.
3rd pass encryption - K.XXHMMDBFEOX.

1. What answer would Zero pass encryption reveal, given that the encryption method does not change.
2. How much more difficult is it to get to zero level encryption if you don't have the level 1 values, only level 2?

(In reply to moderate spoiler on method; but not the answer by Larry)

To go up from the previous pass, you convert the letters there to numbers, and then note all the pairs of letters that would add up to that number (mod 26)

So, with the first letter being M, which is 13, possible pairs of letters that the zero-pass encryption start with are

AL
BK
CJ
....
ZM

For the next letter of the original, I, we again have the following possible pairs of letters:

AH
BG
....
ZI

However, this time our choice is constrained by our previous choice: the first letter of this pair is the last letter of the last.

Which means that we could have as many possible answers as there are initial pairs, which happen to be 26.

The hint at the top seems to means "start with S, though." This gives us:

STOQ.L

As the first five letters, at which point we realize that this can't be right.

It's a good code, though, and could be solved even without a clue as you'd only have to search through about ten strings - most pairs of initial letters can be excluded from the start.

And, in answer to the second question, from the second pass encryption there are 26x26 possible zero-pass strings. At this stage I'd use a computer.

Posted by Sam on 2004-12-01 09:46:20