# Oh, this puzzle

Oh, this puzzle.

To prevent you from answering it, I have a muzzle.

Relax on that sofa, and nuzzle.

The answer to this puzzle, is subtle.

It shall make your brain shuttle.

From Point A to Point B, you will scuttle.

The key is the margin.

Like a wall, that you barge in.

Oh, that doesn't make sense.

Before I forget, the funny slang is the key word, isn't that just common sense? And ignore this line's margin!

Using the above poem, decrypt the phrase below

ETLN DI GIHILKF ILFANON, cpek'b ocf?

• Seems like playfair Sep 21 '16 at 16:15
• @greenturtle3141 You're close, but it's not exactly playfair. Sep 21 '16 at 16:45
• Similar to playfair would be two-/four-square cipher.
– user14478
Sep 21 '16 at 17:05
• @LukasRotter Close again, but it's not exactly that. Sep 21 '16 at 17:07

GOOD AT SOLVING CIPHERS, aren't you?
"Margin" refers to the first letters of each line of the riddle, except the last one, i.e. otrtiftlol (= otrifl with removed repetitions). Using this as a key in the Bifid cipher (as indicated by "turn J into I" and OP's comments under the question) you get the plaintext above.