SMS = short message service = text messaging.

The idea of an SMS cipher involves the numeric keys with the alphabet on your phone.

Credit for this goes to cuzimbob (bobby@cuzimbob.com).

It’s essentially a substitution cipher.

Plaintext A = 2, translating to text 2 = A, B or C.

So let’s take a section of K4 and see what possible combinations we can get.

UOXOGHULBSOLIFBBWFLRVQQPRNGKSSO

Let’s flip it vertically

TUV
MNO
WXYZ
MNO
GHI
GHI
TUV
JKL
ABC
PQRS
MNO
JKL
GHI
DEF
ABC
ABC
WXYZ
DEF
JKL
PQRS
TUV
PQRS
PQRS
PQRS
PQRS
MNO
GHI
JKL
PQRS
MNO

The challenge becomes something similar to an anagram challenge.  You can form quite a few different kinds of messages but to find one message that uses them all in a regular, algorithmic fashion that uses all of the available characters is quite difficult.  Having certainty that you have the absolute correct message is dubious.

cuzimbob actually originall suggested something different but I wanted to take a look at this first way out of curiosity.  Bobby’s suggestion was that you convert the letters to numbers with the phone pad and then “type” them back out.  In this way 777 would = S.  Unfortunately this seems to involve two different steps to encipher and decipher.  Enciphering would involve taking the plaintext and converting to the actual numbers needed in an SMS text, for instance in this case the plaintext S would become 777.  The sevens are taken individually and can become either a P, Q, R or S.  These individual ciphertext letters then are deciphered with the keypad into the individual numbers and number repeats become one unit of plaintext.  The idea is intriguing and allows for some fractionation of the text.  Ultimately you will end up with less plaintext then ciphertext.

It’s an opinion but I think K4 needs to decipher back to 97 letters.

We can’t discount the SMS cipher system but I don’t have the resources to compute possible English transcripts from the K4 ciphertext.  It reduces the possible characters but there’s still a lot of variability left.

If it is an SMS cipher system we’ll need some clues.

If it is and we don’t get some clues then I’ll never be able to figure it out and can only hope someone else can rule this one out.

My final verdict is no however.

Just a feeling.