The American Cryptogram Association
The American Cryptogram Association (ACA) is a non-profit organization dedicated to promoting the hobby and art of cryptanalysis -- that is, learning to break ciphers.

Log-in procedure changes

Members, please note that the login procedure has changed. The members menu now has only a single “log in” entry for non-logged-in visitors to the web site. Members may use this page to log in
the usual way, after which they should have all options they’re used to seeing. Please contact webmaster AT cryptogram DOT org if you have problems or suggestions for making the login/member area access easier to use. And thanks for your patience.


PayPal If you wish to use PayPal for paying your ACA dues or ACA For Sale items, please refer to the instructions on the membership page.

Free Web App. The ACA’s “Solve a Cipher!” program is now available as a free web app under the Resources tab. To access it, click HERE.

Tutorials for Sample Issue We now have tutorial solutions for all the ciphers in the free Sample Issue of The Cryptogram. Get your solving effort started with a nudge or follow along to see the complete solution of the cipher. It’s like looking over the shoulder of a friend solving a cipher.

THE RAT has upgraded his Conmaker program by adding the following cipher types in the “More Types” menu: CONDI, Nicodemus, Nihilist Substitution, Numbered Key, Phillips, Route, Sequence. The format of the program is slightly smaller and some minor error corrections and cosmetic changes were made. It is designed for Windows users to easily create and submit cons to the ACA column editors. If interested, go to the Members Area / Downloads and get your copy.