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.

Join Us!

Now is an ideal time to join the ACA. While supplies last, new members will receive a CD-ROM containing the contents of The Cryptogram from 1932 to 2009. For information on membership benefits and details on how to join see Membership.



2015 Cryptologic History Symposium

At John Hopkins University, MD starting Thu Oct 27, 2015. Read More


If you wish to use PayPal as an option for paying your ACA dues or ACA For Sale items, please refer to the instructions on the membership page and use the fee calculator to get the correct amount.

Free Web App.

The ACA's "Solve a Cipher!" program is now available as a free web app for users of Google's Chrome web browser. To get it, click HERE, or go to the Chrome Web Store and search on "ciphers".

New Expanded Free Sample Issue

The free sample issue of The Cryptogram available for download has been expanded with more explanations and many more ciphers to solve. Read about it and download it on the Sample Issue page under About the ACA .

2nd Edition PHOENIX Memorial CDROM

A member reported that the links on the index page of the 2nd Edition PHOENIX Memorial CDROM did not work with Acrobat Reader v9. It turned out to be caused by the default value of a preference option. Here is how it was corrected:


Documents->View Documents in PDF/A mode: NEVER

From the Edit menu, select "Preferences", then choose to look under Category "Documents".

The option "View Documents in PDF/A mode" should be changed to "Never".

FBI Code Breaking Challenge.

The FBI has a website with a code breaking challenge. Check it out.

THE RAT has made available for ACA members a program called Conmaker. 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.



2015 ACA Annual Convention Washington, DC-Chantilly, VA

Last minute information about sightseeing during the convention: Click here

ACA’s 2015 convention will take place in Chantilly, VA, a suburb of Washington, DC, August 28-30, 2015. Your hosts, G-MAN ( and ASYMPTOTE (, have made arrangements and plans to ensure this is a most pleasurable and enlightening event.

We hope you will join fellow members of the Krewe in this opportunity to meet and interact with others who share your enjoyment of what is admittedly a pretty specialized area of interest. Come and share your knowledge of cryptology—from historical aspects to solving methods—with fellow members. During your visit, take advantage of the opportunity to do some sightseeing in the Washington, DC, area, with its surfeit of historical and educational sites, many of which have no admission fee.

The convention hotel will be the Wingate by Wyndham Hotel Chantilly-Dulles, located at 3940 Centerview Drive, Chantilly, VA, 20151; telephone: 571-203-0999. We have negotiated a rate of $89.00 per night (plus 12% city and state taxes). These rates apply during the period August 25-30.
It also may be possible to receive this discounted rate for dates outside the group block period, depending on room availability. We already know that several members will arrive Wednesday the 26th and stay until Monday the 31st.

The hotel offers its guests all of the usual amenities, including free 24-hour shuttle service to and from Dulles International Airport (IAD); complimentary hot breakfast; free local and 1-800 access calls; free in-room wired and wireless Internet access and telephones; a 24-hour business center that includes use of fax, copier, and computers; in-room flat-screen TV, microwave, refrigerator, coffee maker, etc.; as well as an indoor pool, fitness center and whirlpool.

Hotel reservations may be made now, but must be made by August 1, 2015, to be eligible for the group rate. Please call the hotel directly at 571-203-0999 and identify yourself as a member of the “American Cryptogram Association.” (Do not make your reservation through a travel agent or on-line: This will ensure that you get the group rate. It also gives ACA credit with the Wingate for your attendance, which helps keep convention costs down.).

A wide range of activities is being considered for the Krewe, including sight-seeing, museums tours (including the Smithsonian, National Gallery of Art, Museum of the American Indian, to name only a few of the many), visits to privately-operated museums such as the Museum of Crime and Punishment, Civil War battlefield tours, and shopping.

For those with an interest in things aeronautical, the Udvar-Hazy Center, an adjunct of the Smithsonian Institution’s National Air and Space Museum, is located only a few minutes from our hotel. There, you will have an opportunity to see the Space Shuttle Discovery, the SR-71 Blackbird, the B 29 bomber Enola Gay, and numerous other aircraft—virtually the full spectrum from old biplanes to today’s jets and rockets. Their IMAX theater shows several informative, memorable movies; find out more at

Depending on the expressed interests of the Krewe, we will have group field trips on Friday and Sunday. You will have the opportunity to indicate your preferences on the registration form in The Cryptogram.

By the way, if a planned activity is not of interest to you, or maybe you’ve seen it a few times already, feel free to do something different. Your hosts know the DC area quite well and are definitely willing to assist you in this.

The convention’s “main events” take place on Saturday. However, one of our activities is the Friday evening pizza party, cipher-solving party, meet-and-greet, and the like. Be assured that this is a convention highlight—don’t miss it! Of course, we will hold our annual Business meeting on Sunday morning.

We know that the Krewe has many very knowledgeable solvers, and we invite you to make a presentation. If you have an interest in doing this, please contact one of your hosts. Share your knowledge of our hobby!

More to come . ..
Further details concerning our convention agenda will be published in the next issue of The Cryptogram. Updates also will appear here . . . watch this space!