You guys solved my last cipher puzzle remarkably quickly; here's a harder one to mull over.

You are given the following plaintext/ciphertext pairs:






image 1 Let the whole world know that today is a day of reckoning.







image 2 But her dreams give her wings, and she flies to a place where shes loved.









image 3 Another bruise to try and hide, another alibi to write. Another lonely highway in the black of night.

Derive the plaintext that corresponds to the following cipher text:



|+.-X+.OX.-X-+.O|X+|., +.O+|+.X+|-



image 4

  • $\begingroup$ Can we have a transcription? This seems tedious to transcribe. $\endgroup$
    – Deusovi
    Jun 17, 2017 at 1:32
  • $\begingroup$ @Deusovi Sure, though it'll take me a bit; give me a few minutes. $\endgroup$ Jun 17, 2017 at 1:34
  • $\begingroup$ @Deusovi I just finished the first transcript; that should give you something to work with as I work on the others. $\endgroup$ Jun 17, 2017 at 1:44
  • $\begingroup$ @Deusovi Transcripts are done. $\endgroup$ Jun 17, 2017 at 2:04

1 Answer 1


Here is how it works:

Letters are converted into numbers in the usual A1Z26 way. Each number is expressed as a sum of powers of 2 in descending order and these are converted into symbols: O=16, X=8, +=4, |=2, .=1. The horizontal bar (which I suppose we should consider as a zero) indicates a space but is also used to separate groups that would otherwise be ambiguous: e.g., TA can't be written as O+. because that would mean U and must instead be written O+-.. When there is a word-break and a "heavier" symbol is followed by a "lighter", a right-arrow is used instead of a horizontal bar. And of course the up-arrow is used to preface a capital letter.

I'm not very happy with my explanation of the horizontal bar and right-arrow there, so let me try again.

Say that a "word break" occurs between letters when there is a space in the plaintext, and that a "bit break" occurs when the first letter's last symbol is "heavier" than the second letter's first. In either of these cases we need an explicit marker of the separation between letters. We use a horizontal bar when just one of these things occurs (and can therefore tell when it denotes an actual space by looking at the symbols on either side), and a right-arrow when both do (so it always denotes an actual space).

The last message says:

But youll always be my hero, even though youve lost your mind.

(Regrettably, there is no encoding for apostrophes.)

  • $\begingroup$ I'm wholeheartedly impressed at how fast you solved this one. $\endgroup$ Jun 17, 2017 at 2:55
  • $\begingroup$ There's two symbols that you haven't quite figured out: the up arrow, and the right arrow. $\endgroup$ Jun 17, 2017 at 2:56
  • $\begingroup$ It was obvious very quickly that (1) this was probably a substitution cipher, (2) there were multiple symbols per letter, and (3) different letters had symbols of different lengths. I actually noticed the "adding a dot gives one letter later" pattern some time ago but didn't have the courage of my convictions :-). $\endgroup$
    – Gareth McCaughan
    Jun 17, 2017 at 2:57
  • $\begingroup$ Oh, sorry, the up-arrow was actually the first thing I worked out and I forgot to mention it. Will fix. $\endgroup$
    – Gareth McCaughan
    Jun 17, 2017 at 2:57
  • $\begingroup$ ... Fixed. (And fixed up the upper/lower case relationships in the transcription. I have a habit of putting things in all-caps, which was not appropriate here.) $\endgroup$
    – Gareth McCaughan
    Jun 17, 2017 at 2:58

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