| Double Columnar Transposition | 100 | Dec. 1, 2016, 9:48 p.m. |
| RSA: Two different keys — same ciphertext | 1,098 | Nov. 29, 2016, 7:43 p.m. |
| How do you become a big cryptographer? | 100 | Nov. 29, 2016, 9:08 a.m. |
| Modified Caesar Cipher | 100 | Nov. 27, 2016, 12:17 p.m. |
| From Russia with Love | 100 | Nov. 27, 2016, 1:56 a.m. |
| Grille Cipher | 100 | Nov. 27, 2016, 1:17 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Nov. 27, 2016, 12:57 a.m. |
| Letter to the Templars — Part 3 | 1,105 | Nov. 27, 2016, 12:27 a.m. |
| A hidden word | 100 | Nov. 26, 2016, 11:45 p.m. |
| Letter to the Templars — Part 2 | 100 | Nov. 26, 2016, 11:42 p.m. |
| Letter to the Templars — Part 1 | 100 | Nov. 26, 2016, 11:30 p.m. |
| Beaver Code | 100 | Nov. 26, 2016, 11:07 p.m. |
| Factorization Cipher — Part 3 | 1,101 | Nov. 25, 2016, 11:50 p.m. |
| The Book Code: A Challenge for Bookworms | 100 | Nov. 24, 2016, 10:19 p.m. |
| Number Sequence — Part 4 | 100 | Nov. 23, 2016, 8:20 p.m. |
| Number Sequence — Part 3 | 100 | Nov. 23, 2016, 8:08 p.m. |
| RSA Factoring Challenge: RSA-210 | 0 | Nov. 23, 2016, 8:42 a.m. |
| Factorization Cipher — Part 2 | 1,100 | Nov. 22, 2016, 8:51 p.m. |
| Factorization Cipher — Part 1 | 100 | Nov. 21, 2016, 6:54 p.m. |
| Hybrid Encryption I | 1,095 | Nov. 21, 2016, 11:23 a.m. |
| Snow White and the seven dwarfs | 100 | Nov. 19, 2016, 11:25 p.m. |
| Nils away on travel | 100 | Nov. 19, 2016, 10:55 p.m. |
| M-138 — Part 1 | 100 | Nov. 17, 2016, 3:19 p.m. |
| A hidden word — Part 2 | 100 | Nov. 17, 2016, 10:47 a.m. |
| Number Sequence — Part 8 | 100 | Nov. 16, 2016, 10:31 p.m. |
| Cracking SHA1-Hashed Passwords | 1,220 | July 30, 2011, midnight |
| Kaskade-S/T — Part 1 | 101 | July 26, 2011, 6:11 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,725 | July 25, 2011, 2:38 a.m. |
| One-Time Pad with Flaws | 100 | July 23, 2011, 4:17 p.m. |
| Original Caesar Cipher | 100 | July 23, 2011, 2:21 a.m. |
| Number Sequence — Part 2 | 108 | July 22, 2011, 11:12 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 133 | Oct. 24, 2010, 3:33 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 133 | Oct. 24, 2010, 3:17 p.m. |
| Caesar Encryption | 133 | Oct. 24, 2010, 2:44 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,523 | Oct. 22, 2010, 2:01 a.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,613 | Oct. 19, 2010, 1:28 p.m. |
| Alice's Birthday Party (Part 2) | 1,613 | Oct. 18, 2010, 7:43 p.m. |
| Alice's Birthday Party (Part 1) | 1,613 | Oct. 18, 2010, 7:08 p.m. |
| A Secret Message from Castle Mansfeld | 200 | Oct. 15, 2010, 1:34 a.m. |
| Classical Ciphers^3 | 200 | Oct. 15, 2010, 1:32 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 200 | Oct. 15, 2010, 1:31 a.m. |
| Monoalphabetic Substitution | 200 | Oct. 15, 2010, 1:30 a.m. |
| Number Sequence | 200 | Oct. 15, 2010, 1:30 a.m. |
| Zodiac Cipher | 200 | Oct. 15, 2010, 1:29 a.m. |