A waiter spotted a happy customer which, after finishing his meal, lit a cigar, ignoring the big sign "No smoking allowed."
Approaching the smoker, the waiter asked politely in a soft and friendly voice:
:
"Excuse me, Sir, didn't you happen to notice the sign displayed just in front of you?"
Exhaling a perfect ring of smoke, the jolly fellow quipped:
..." I did, but M'P MDM DPDBMMD AHDPP."

Rem: the puzzle's encryption was not by a simple substitution code , but rather via N(CODE)=N(TEXT)mod K + L or similar (like F(N)instead of N), where N is the ordinal value of a letter in English ABC and K, L integers to be found.

After trying to find words that fit various combinations of k and l, I tried guessing the joke. The letter count fits "I'M NOT SMOKING ALOUD", the the mod value doesn't look consistent for that. For example I and N having the same code value indicate k=5, but D for G implies k=3, as does P for M.

Posted by Charlie on 2014-10-12 10:39:32