From the personal library of and in memory of RISHU

From December 13, 1924 until September 29, 1928, FLYNN's [Detective] [Fiction] [Weekly] published a series of articles about Solving Ciphers, Edited by Crypto Pioneer Merle E. Ohaver.

s a direct result of these articles, the American Cryptogram Association was formed on September 1, 1929

For your solving pleasure, we have scanned and made available all of these original articles both in the original PDF form and a much more readable HTML page.

TRY YOUR WITS ON THE GREAT CODES AND CRYPTOGRAMS IN
WHICH MEN HAVE MASKED THEIR MESSAGES OF LIFE AND DEATH

1924	1926
December 13, 1924 - scytale cipher ——Index of 1924 ciphers——	January 2, 1926 - Grille solving January 23, 1926 - Digraph Frequency February 20, 1926 - Vigenère cipher March 20, 1926 - Nihilist Transposition cipher April 24, 1926 - Æneas Tacticus dot cipher May 22, 1926 - Book cipher July 3, 1926 - Anagrams and Transposition ciphers August 7, 1926 - The Kasiski Principle September 4, 1926 - Identifying Unknown ciphers October 2, 1926 - Arthur B. Reeve cipher November 13, 1926 - Solutions Explained December 18, 1926 - Radio cipher Explained ——Index of 1926 ciphers——
1925
January 17, 1925 - null cipher February 21, 1925 - Augustus cipher March 28, 1925 - Nihilist Numerical cipher April 25, 1925 - Bilateral cipher May 16, 1925 - Poe cipher June 06, 1925 - Gronsfeld cipher June 27, 1925 - Solving Nihilist cipher July 25, 1925 - William Blair's cipher August 15, 1925 - Blair's cipher revealed September 9, 1925 - Frequency Tables October 10, 1925 - Fan Chat October 31, 1925 - Solving Hints December 5, 1925 - Grille cipher ——Index of 1925 ciphers——
1927	1928
January 22, 1927 - Key Phrase cipher March 5, 1927 - Charles Ⅰ stroke cipher March 12, 1927 - Cipher Rule #1 March 19, 1927 - Introduction of Cryptograms March 26, 1927 - What is a Cryptogram? April 2, 1927 - Solution for March 5 April 9, 1927 - Salad for the Solitary April 16, 1927 - Ciphers 12,13 and Friendly Fans April 23, 1927 - Simplex Cryptograph System April 30, 1927 - Principles of Cipher Structure May 7, 1927 - Solutions to National Puzzler's League Contest May 14, 1927 - Autokey cipher May 21, 1927 - Solving Autokey cipher May 28, 1927 - 10 Cipher System Standards June 4, 1927 - Cipher Rule #2 June 11, 1927 - Cipher Rule #3 June 18, 1927 - Solutions to Ciphers 27,28,29 June 25, 1927 - Cipher Rule #5 July 2, 1927 - Variation by supplementary keys July 9, 1927 - Cipher Rule #7 July 16, 1927 - Puzzler's League Crypt Winners July 23, 1927 - Explanation of Autokey Cipher 19 July 30, 1927 - Ciphers which avoid suspicion August 6, 1927 - Explanation of Cipher #44 August 13, 1927 - Cyphral Distich, Explanation of 51, 52 August 20, 1927 - Explanation of Cipher 50 August 27, 1927 - Explanation of Cipher 44 September 3, 1927 - The athbash Bible cipher September 10, 1927 -Solution to Garden Wall cipher September 17, 1927 - Myszkowski Transposition Cipher September 24, 1927 - Simplifying Myszkowski Cipher, Jumbled Crypts October 1, 1927 - Solving a difficult Transposition Cipher October 8, 1927 - "Mixed" Digraph test for Transposition Cipher October 15, 1927 - Computing Intervals for Transposition Cipher October 22, 1927 - Determining Key Length of Transposition Cipher October 29, 1927 - Finding Numerical Key of Cipher No. 73 November 5, 1927 - Solution to Cipher No. 73 November 12, 1927 - Solution to Cipher No. 47 November 19, 1927 - Solution to Cipher No. 88 November 26, 1927 - Explanation of Transposition Cipher No. 90 December 3, 1927 - Attacking Cipher No. 100 December 10, 1927 - U.S. Army "Double Transposition" Cipher December 17, 1927 - Solving a straight substitution cipher December 24, 1927 - How to find original key for "Double Transposition" Ciphers December 31, 1927 - Using a second numerical sequence to determine a cipher key ——Index of 1927 ciphers—— ——1927 The National Puzzlers' League Contest Crypts—— ——1927 Simplex Cryptograph Code Messages——	January 07, 1928 - Exposing vulnerable spots in double transposition ciper January 14, 1928 - Determine literal keys to numeric transposition ciphers January 21, 1928 - Answers to previous week January 28, 1928 - New variation of "Double Transposition Cipher" February 04, 1928 - Playfair Cipher February 11, 1928 - Solution to PlayFair Cipher No. 129 February 18, 1928 - Playfair Ciphers Part 3 February 25, 1928 - Characteristic Earmarks of Playfair Ciphers March 03, 1928 - Solution to Cipher No. 136 March 10, 1928 - Phonetic Alphabet Ciphers March 17, 1928 - Continuing Phonetic Alphabet Ciphers March 24, 1928 - Solutions to 145 and 147, New List of solvers March 31, 1928 - Solution to Cipher No. 148 April 07, 1928 - Explanation of Cipher No 127. April 14, 1928 - Price Mark Cipher April 21, 1928 - Price Mark Cipher Continued April 28, 1928 - Magic Square Cipher May 05, 1928 - De La Loubère Square as a cipher key May 12, 1928 - "Knight's Tour" discussion May 19, 1928 - Grandpré 10x10 Square May 26, 1928 - Explanation of Cipher No 175 June 02, 1928 - Explanation of Open Letter Cipher No 178 June 09, 1928 - Solution to the Legrand Open Letter Cipher June 16, 1928 - The Porta cipher June 23, 1928 - Solution to the Porta cipher June 30, 1928 - The Porta System as a Simple Machine Cipher July 07, 1928 - Determining Key Length of Multi-Alphabet Cipher August 04, 1928 - King Charles I Cipher August 11, 1928 - Solution to King Charles I Cipher September 22, 1928 - Ingenious Solutions to Previous Ciphers September 29, 1928 - Cryptogram sizes ——Index of 1928 ciphers——

From the personal library of and in memory of RISHU

1924 Ciphers

1925 Ciphers

1926 Ciphers

1927 The National Puzzlers' League Contest Crypts

1927 Simplex Cryptograph Code Messages

1927 Ciphers

1928 Ciphers