| Alberti Challenge — Part 1 | 101 | June 22, 2022, 8:25 p.m. |
| Summer Job | 1,106 | June 22, 2022, noon |
| Wheatstone Cryptograph — Part 1 | 100 | June 21, 2022, 11:06 p.m. |
| M-138 — Part 2 | 1,113 | March 22, 2018, 9:32 p.m. |
| Advent-Challenge — Part 2 | 1,236 | March 19, 2018, 2:50 p.m. |
| Number Sequence — Part 8 | 100 | March 16, 2018, 8:35 a.m. |
| Advent-Challenge — Part 1 | 101 | March 16, 2018, 8:08 a.m. |
| ¿No Hablas Español? No problemo! | 100 | April 14, 2015, 10:12 p.m. |
| Trifid Cipher | 100 | April 14, 2015, 9:29 p.m. |
| M-138 — Part 1 | 101 | April 9, 2015, 9:09 p.m. |
| Number Sequence — Part 5 | 100 | Sept. 3, 2014, 10:15 p.m. |
| Nils away on travel | 100 | Aug. 30, 2014, 9:52 p.m. |
| RSA Factoring Challenge: RSA-704 | 0 | Aug. 30, 2014, 8:44 p.m. |
| RSA Factoring Challenge: RSA-210 | 0 | Aug. 30, 2014, 8:39 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | Aug. 29, 2014, 10:36 p.m. |
| Heartbleed — Part 2 | 200 | Aug. 28, 2014, 11:11 p.m. |
| Heartbleed — Part 1 | 200 | Aug. 28, 2014, 10:31 p.m. |
| From Russia with Love | 100 | Aug. 28, 2014, 9:33 p.m. |
| Factorization Cipher — Part 2 | 1,133 | Sept. 12, 2013, 2:36 p.m. |
| Keyshanc — Part 1 | 1,146 | Sept. 11, 2013, 5:44 p.m. |
| Pigpen with a twist — Part 1 | 100 | Sept. 10, 2013, 2:20 p.m. |
| How do you become a big cryptographer? | 100 | Sept. 9, 2013, 5 p.m. |
| Reserve Hand Procedure — Part 1 | 101 | Sept. 2, 2013, 4:27 p.m. |
| A hidden word | 100 | Aug. 21, 2013, 10:59 a.m. |
| Snow White and the seven dwarfs | 105 | May 9, 2013, 2:32 p.m. |
| Letter to the Templars — Part 3 | 1,523 | Oct. 16, 2012, 5:39 p.m. |
| Letter to the Templars — Part 2 | 101 | Oct. 16, 2012, 5:20 p.m. |
| Letter to the Templars — Part 1 | 101 | Oct. 16, 2012, 5:14 p.m. |
| Beaver Code | 102 | Oct. 16, 2012, 4:42 p.m. |
| Number Sequence — Part 4 | 113 | April 26, 2012, 2:35 p.m. |
| Number Sequence — Part 3 | 108 | April 12, 2012, 1:03 p.m. |
| The Book Code: A Challenge for Bookworms | 133 | March 23, 2012, 1:28 p.m. |
| RSA: Two different keys — same ciphertext | 1,184 | March 16, 2012, 8:41 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,362 | March 5, 2012, 3:41 p.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,288 | March 4, 2012, 10:18 p.m. |
| Factorization Cipher — Part 1 | 200 | Oct. 18, 2011, 11:45 a.m. |
| Grille Cipher | 133 | Oct. 17, 2011, 1:12 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,251 | Oct. 5, 2011, 9:35 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,158 | Oct. 4, 2011, 9:49 p.m. |
| A really long number sequence | 1,502 | Sept. 14, 2011, 10:37 a.m. |
| Modified Caesar Cipher | 109 | Sept. 12, 2011, 9:51 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 125 | Sept. 12, 2011, 3:24 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 101 | Aug. 9, 2011, 9:41 a.m. |
| Number Sequence — Part 2 | 103 | Aug. 9, 2011, 8:47 a.m. |
| Cracking SHA1-Hashed Passwords | 1,349 | May 1, 2011, 5:51 p.m. |
| Enigma Part 2 | 1,202 | March 20, 2011, 10:11 a.m. |
| Kaskade-S/T — Part 3 | 1,444 | March 16, 2011, 9:24 p.m. |
| Playfair Encryption | 101 | March 11, 2011, 3:32 p.m. |
| Classical Ciphers^3 | 101 | March 10, 2011, 8:46 p.m. |
| Kaskade-S/T — Part 2 | 1,576 | March 9, 2011, 6:25 p.m. |
| Kaskade-S/T — Part 1 | 133 | March 6, 2011, 2:25 p.m. |
| Enigma Combinatorics | 101 | Feb. 23, 2011, 5:47 p.m. |
| Hybrid Encryption I | 1,242 | Jan. 26, 2011, 1:10 p.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,725 | Jan. 16, 2011, 7:26 p.m. |
| ORYX Stream Cipher Part II | 1,235 | Jan. 16, 2011, 11:55 a.m. |
| ORYX Stream Cipher Part I | 1,236 | Jan. 14, 2011, 8:39 p.m. |
| Alice's Birthday Party (Part 2) | 1,244 | Jan. 5, 2011, 6:16 p.m. |
| Alice's Birthday Party (Part 1) | 1,244 | Jan. 5, 2011, 6:14 p.m. |
| Molehunt (Part 3/3) | 1,279 | Dec. 16, 2010, 6:02 p.m. |
| Molehunt (Part 2/3) | 102 | Dec. 15, 2010, 10:22 a.m. |
| Original Caesar Cipher | 200 | Dec. 15, 2010, 9:01 a.m. |
| Molehunt (Part 1/3) | 102 | Dec. 14, 2010, 7:44 p.m. |
| Enigma Part 1 | 1,275 | Dec. 10, 2010, 11:44 a.m. |
| A Secret Message from Castle Mansfeld | 102 | Dec. 8, 2010, 5:52 p.m. |
| Zodiac Cipher | 102 | Dec. 8, 2010, 1:49 p.m. |
| Caesar Encryption | 102 | Dec. 7, 2010, 11:05 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,278 | Dec. 7, 2010, 10:34 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 102 | Dec. 5, 2010, 9:41 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 102 | Dec. 5, 2010, 9:09 p.m. |
| One-Time Pad with Flaws | 104 | Dec. 5, 2010, 8:23 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 125 | Oct. 18, 2010, 1:10 p.m. |
| Monoalphabetic Substitution | 125 | Oct. 18, 2010, 11:05 a.m. |
| Number Sequence | 125 | Oct. 18, 2010, 9:54 a.m. |