attribution
ciphergram
ciphertext
CSA
plaintext
initial key

The attribution is the ciphergram author's name. In the newspaper puzzles, this is the ciphertext that follows the dash near the end. You do not have to enter it; it is optional. The CSA will decipher the ciphertext in the attribution window with the key derived from the ciphertext in the ciphergram window.

Enter the attribution ciphertext (if any) in the attribution window (second from top).

A ciphergram is a short message that has been transformed by a so-called simple substitution cipher.

The Ciphergram Solution Assistant (CSA) is designed to solve, or nearly solve, ciphergrams like those in some newspapers, which are called cryptoquotes. For these puzzles, the ciphertext to plaintext mapping is such that no ciphertext letter may stand for itself in plaintext. The CSA provides an option to relax this rule, in case you think the puzzle you want to solve does not obey it.

Example of a simple substitution cipher:

The well-known Caesar shift is a simple substitution cipher wherein the ciphertext is made from the plaintext by substituting for each letter the one three places to the right in the alphabet, modulo 26: A becomes D, Y becomes B, M becomes P, and so on. Obviously, one deciphers a message that was enciphered with the Caesar Shift by substituting the letter three places to the left in the alphabet, modulo 26, for each ciphertext letter. Therefore, the deciphering key in this case is: D becomes A, B becomes Y, P becomes M, and so forth.

Ciphertext is an enciphered message or part of one.

In the case of a simple substution cipher, ciphertext is made from a clear message (the plaintext) by translating, using a key, the letters of the words one letter at a time.

The key is a list of plaintext letters and their corresponding enciphered letters.

CSA is an acronym for the Ciphergram Solution Assistant (this program).

Plaintext is a clear message or part of one.

In the case of a simple substution cipher, plaintext is made from ciphertext by translating, using a deciphering key, the letters of the words one letter at a time.

The deciphering key is a list of ciphertext letters and their corresponding plaintext letters.

The initial key is a list of letter pairs separated by spaces. The first of each pair is a ciphertext letter, and the second of each pair is the corresponding forced plaintext letter.

For example, to force ciphertext B to mean plaintext H and ciphertext F to mean plaintext L, the initial key window would contain:

BH FL

Case is not important, nor do the pairs have to be in any particular order. No characters other than letters and spaces are allowed in the initial key.

Last updated 2002 September 17