# The Phoenix Cypher

I have a challenge for you people. Solving the following cypher will prove this website's ability. It is a teaser for an incoming puzzle hunt across the internet:

Hqfwp pz poqy. Ujcfsjvt, gdko!

Clark is back. Tiberius, help!

The cipher is

Rot-N, with N changing between each word. The decryption values are 21, 19, 12, 25 and 1, so the original N are 5,7,14,1 and 25. Neither "uslya" or "egnay" says anything to me, and neither do the rotations of those words, so the meaning of the code sequence is unclear to me.

UPDATE:

OP has informed us (in a comment to this answer) that the meaning of the key is

A non-dictionary word, used as a family name of never-seen-before fictional characters, spelled backwards. Or to call a spade a spade, the key has absolutely no meaning whatsoever.

Given that this would be extremely dissatisfying for anyone trying to find said meaning, I constructed a new headcanon that will probably leave you just as dissatisfied, but maybe at least a bit amused. Here it is:

The encryption method actually has a slightly better "key scrambling" step than just the suggested reversing. The entire method goes like this:

1. Choose a password that has at least as many letters as the plaintext message has words.
2. Count the number of letters in the password
3. Scramble the password in two steps:
3.1 Shift each letter backwards in the alphabet by the password length.
3.2 Then, replace each letter with the corresponding one in a reversed alphabet. Only after this scrambling,
4. Use the letters of the password, one by one, as keys to encrypt the individual words in the plain text message, in the Vigenèresque manner described in the actual answer above.

Now, given that the encryption scheme isn't exactly the most foolproof imaginable, it stands to reason that the sender(s) cannot exactly be called "security aware", so they would probably use an easy-to-guess word (like their name or something like that) as the password. This all fits together with the original puzzle and its stated Japanese-like connotations, as long as the message was sent by a (and encrypted using the password of)

CATGIRL

...yeah.. not really all that satisfying either, is it now. Warned you, though. :-)

• Bah. I saw that you posted an answer while I was writing up mine, but figured I'd at least get the reasoning in... and then you added the reasoning before I got to finish formatting mine. Good job. Dec 27, 2017 at 23:46
• Ouch, been in the same position a couple of times myself. Well, at least we agree, so I can upvote your answer :-)
– Bass
Dec 27, 2017 at 23:54
• Correct. You have proven this site worthy. If you read the second coding sequence backwards, it spells Yange - the pronouncination of the Japanese word for sharp. It also sounds like a last name so it is either Tiberius Yange or Clark Yange. I wish you luck with hunting him down. Dec 28, 2017 at 10:46

As Bass just posted while I was writing this up, the answer appears to be:

Clark is back. Tiberius, help!

This is found by:

Shifting each word by a specific number of letters:
* "Hqfwp" - 5 = Clark (also +21)
* "pz" - 7 = is (also +19)
* "poqy." - 12 = back (also +14)
* "Ujcfsjvt," - 25 = Tiberius, (also +1)
* "gdko!" - 1 = help! (also +25)

I don't notice any particular pattern to this, and I can't find anything for this sequence on OEIS, so brute force is the only way I see to have found it.

• 23 + 1 doesn't add up to 26. The 23 should be 25.
– Bass
Dec 27, 2017 at 23:48
• Ack, math error! Thanks for pointing that out. Fixed, but I probably should just delete this, though. It doesn't add anything to your answer, and you were there first. Dec 27, 2017 at 23:49