| Enigma Messages with Repeated Letters — Part 5 | 120 | March 10, 2014, 1:48 a.m. |
| Enigma Messages with Repeated Letters — Part 4 | 120 | March 10, 2014, 1:48 a.m. |
| Enigma Messages with Repeated Letters — Part 3 | 120 | March 10, 2014, 1:46 a.m. |
| Enigma Messages with Repeated Letters — Part 2 | 101 | March 10, 2014, 1:46 a.m. |
| Enigma Messages with Repeated Letters — Part 1 | 150 | Sept. 27, 2013, 6:38 p.m. |
| From Russia with Love | 150 | Sept. 6, 2013, 1:02 p.m. |
| Nils away on travel | 133 | Aug. 10, 2013, 11:16 p.m. |
| A hidden word | 101 | April 10, 2013, 3:29 p.m. |
| Cascading Encryption — Part 1/3 | 102 | March 30, 2013, 3:27 p.m. |
| Reserve Hand Procedure — Part 1 | 200 | March 7, 2013, 5:17 p.m. |
| Multilingual Monoalphabetic Substitution | 150 | Feb. 1, 2013, 1:50 p.m. |
| Playfair with hints about the grid | 125 | Jan. 20, 2013, 9:34 a.m. |
| Beaver Code | 200 | Aug. 13, 2012, 9 p.m. |
| Number Sequence — Part 4 | 105 | May 7, 2012, 1:10 p.m. |
| Number Sequence — Part 3 | 150 | March 31, 2012, 11:27 p.m. |
| The Book Code: A Challenge for Bookworms | 133 | March 23, 2012, 9:46 p.m. |
| Factorization Cipher — Part 2 | 1,284 | Jan. 20, 2012, 9:16 p.m. |
| Factorization Cipher — Part 3 | 1,502 | Jan. 14, 2012, 8:20 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,547 | Dec. 13, 2011, 4:08 p.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,824 | Dec. 8, 2011, 6:35 p.m. |
| Double Columnar Transposition | 104 | Nov. 8, 2011, 2:25 p.m. |
| Turing Bombe Enigma I | 200 | Oct. 18, 2011, 11:54 a.m. |
| Factorization Cipher — Part 1 | 200 | Oct. 17, 2011, 7:11 p.m. |
| Grille Cipher | 200 | Oct. 15, 2011, 12:49 a.m. |
| Pigpen with a twist — Part 2 | 1,456 | Sept. 13, 2011, 7:37 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 200 | Sept. 9, 2011, 3:02 p.m. |
| A really long number sequence | 1,660 | Sept. 9, 2011, 2:35 p.m. |
| Pigpen with a twist — Part 1 | 200 | Sept. 6, 2011, 5:23 p.m. |
| Modified Caesar Cipher | 200 | Sept. 2, 2011, 3:54 p.m. |
| Kaskade-S/T — Part 1 | 101 | Aug. 22, 2011, 2:39 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 101 | Aug. 21, 2011, 10:22 p.m. |
| RSA: Two different keys — same ciphertext | 1,547 | Aug. 21, 2011, 5:54 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,337 | Aug. 21, 2011, 1:13 p.m. |
| ADFGVX — Part 2 | 117 | Aug. 21, 2011, 12:49 a.m. |
| ADFGVX — Part 1 | 117 | Aug. 21, 2011, 12:32 a.m. |
| Number Sequence — Part 2 | 110 | July 20, 2011, 7:32 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,216 | Feb. 14, 2011, 4:42 p.m. |
| Molehunt (Part 3/3) | 1,224 | Feb. 9, 2011, 9:11 p.m. |
| Hybrid Encryption I | 1,235 | Feb. 4, 2011, 3:55 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,222 | Feb. 4, 2011, 9:29 a.m. |
| Molehunt (Part 2/3) | 101 | Feb. 2, 2011, 3:50 p.m. |
| Enigma Part 1 | 1,224 | Feb. 1, 2011, 3:09 p.m. |
| Enigma Part 2 | 1,224 | Feb. 1, 2011, 1:33 p.m. |
| Enigma Combinatorics | 101 | Jan. 31, 2011, 3:30 p.m. |
| Alice's Birthday Party (Part 1) | 1,227 | Jan. 27, 2011, 5:32 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 101 | Jan. 25, 2011, 4:24 p.m. |
| Molehunt (Part 1/3) | 101 | Jan. 24, 2011, 1:53 p.m. |
| Classical Ciphers^3 | 101 | Jan. 23, 2011, 8:13 p.m. |
| Playfair Encryption | 103 | Jan. 23, 2011, 3:31 p.m. |
| Original Caesar Cipher | 103 | Jan. 23, 2011, 2:03 a.m. |
| One-Time Pad with Flaws | 114 | Nov. 18, 2010, 11:04 p.m. |
| Alice's Birthday Party (Part 2) | 1,378 | Nov. 3, 2010, 2:48 p.m. |
| Monoalphabetic Substitution | 105 | Nov. 1, 2010, 1:32 p.m. |
| Caesar Encryption | 109 | Nov. 1, 2010, 8:22 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 110 | Oct. 31, 2010, 5:12 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 110 | Oct. 31, 2010, 4:44 p.m. |
| Number Sequence | 106 | Oct. 31, 2010, 2:21 p.m. |
Gold2
Silver0
Bronze3
