| Advent-Challenge — Part 1 | 100 | June 10, 2022, 10:42 a.m. |
| Autokey Cipher | 100 | June 10, 2022, 10:11 a.m. |
| Wheatstone Cryptograph — Part 1 | 100 | June 8, 2022, 10:32 a.m. |
| Alberti Challenge — Part 1 | 101 | June 4, 2022, 9:22 a.m. |
| From Russia with Love | 101 | Jan. 30, 2014, 8:30 p.m. |
| Cascading Encryption — Part 1/3 | 100 | Aug. 27, 2013, 4:48 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | Aug. 23, 2013, 8:33 p.m. |
| Reserve Hand Procedure — Part 1 | 101 | Aug. 19, 2013, 10:23 p.m. |
| ¿No Hablas Español? No problemo! | 100 | Aug. 19, 2013, 9:23 p.m. |
| ECDH-Key Exchange for Beginners | 100 | Aug. 19, 2013, 4:36 p.m. |
| Nils away on travel | 111 | Aug. 16, 2013, 8:17 p.m. |
| Keyshanc — Part 2 | 1,149 | Aug. 3, 2013, 12:33 a.m. |
| Keyshanc — Part 1 | 1,149 | Aug. 2, 2013, 11:32 p.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,139 | Aug. 2, 2013, 10:16 p.m. |
| Molehunt (Part 3/3) | 1,118 | Aug. 2, 2013, 5:58 a.m. |
| ORYX Stream Cipher Part I | 1,117 | Aug. 1, 2013, 11:08 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,118 | July 30, 2013, 10:42 p.m. |
| Kaskade-S/T — Part 1 | 100 | July 26, 2013, 7:58 p.m. |
| BCR code (Book-Caesar-RSA) | 1,164 | July 24, 2013, 4:36 p.m. |
| A Secret Message from Castle Mansfeld | 100 | July 23, 2013, 8:34 p.m. |
| Modified Caesar Cipher | 100 | July 23, 2013, 12:05 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | July 22, 2013, 10:39 p.m. |
| A hidden word | 101 | July 17, 2013, 12:13 a.m. |
| Classical Ciphers^3 | 100 | July 16, 2013, 11:59 p.m. |
| Enigma Messages | 101 | July 15, 2013, 10:38 p.m. |
| Snow White and the seven dwarfs | 101 | July 15, 2013, 8:36 p.m. |
| Grille Cipher | 100 | July 15, 2013, 7:52 p.m. |
| Letter to the Templars — Part 2 | 100 | July 15, 2013, 6:39 p.m. |
| Enigma Combinatorics | 100 | July 15, 2013, 6:32 p.m. |
| Enigma Part 2 | 1,118 | July 12, 2013, 7:59 p.m. |
| Enigma Part 1 | 1,118 | July 10, 2013, 9:08 p.m. |
| Recycled One-Time Pad | 100 | July 9, 2013, 6:03 a.m. |
| Hybrid Encryption I | 1,119 | July 3, 2013, 11:03 p.m. |
| Unconcealed RSA messages | 1,136 | July 3, 2013, 10:46 p.m. |
| ADFGVX — Part 1 | 100 | June 27, 2013, 6:20 a.m. |
| One-Time Pad with Flaws | 100 | June 26, 2013, 1:09 a.m. |
| Molehunt (Part 2/3) | 100 | June 25, 2013, 4:25 p.m. |
| Molehunt (Part 1/3) | 100 | June 24, 2013, 11:33 p.m. |
| RSA with Special d | 13,681 | June 22, 2013, 5:03 a.m. |
| Partial Key Exposure with RSA — Part 1 | 1,144 | June 18, 2013, 8:55 p.m. |
| Ku Klux Klan | 1,000 | June 16, 2013, 1:44 p.m. |
| Double Columnar Transposition | 100 | June 6, 2013, 9:12 p.m. |
| Pigpen with a twist — Part 1 | 100 | June 6, 2013, 12:04 a.m. |
| Factorization Cipher — Part 3 | 1,142 | June 5, 2013, 7:58 p.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,123 | June 4, 2013, 5:12 p.m. |
| ADFGVX — Part 2 | 100 | June 1, 2013, 4:54 a.m. |
| Factorization Cipher — Part 2 | 1,140 | May 29, 2013, 9:09 p.m. |
| Factorization Cipher — Part 1 | 100 | May 20, 2013, 8:03 p.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | May 19, 2013, 8:35 a.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | May 17, 2013, 9:06 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,120 | May 7, 2013, 6:10 a.m. |
| Letter to the Templars — Part 3 | 1,185 | May 6, 2013, 7:38 a.m. |
| Smartcard RSA | 1,121 | May 3, 2013, 7:03 a.m. |
| A really long number sequence | 1,136 | May 1, 2013, 7:33 p.m. |
| RSA: Two different keys — same ciphertext | 1,135 | April 29, 2013, 8:56 a.m. |
| Broadcasting and low exponent — RSA Attack | 1,134 | April 29, 2013, 6:32 a.m. |
| Cracking SHA1-Hashed Passwords | 1,128 | April 28, 2013, 7:44 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | April 28, 2013, 6:44 p.m. |
| Letter to the Templars — Part 1 | 100 | April 27, 2013, 5:21 p.m. |
| Alice's Birthday Party (Part 2) | 1,121 | April 27, 2013, 8:03 a.m. |
| Alice's Birthday Party (Part 1) | 1,121 | April 27, 2013, 12:01 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | April 24, 2013, 4:31 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | April 24, 2013, 4:22 p.m. |
| Number Sequence — Part 4 | 100 | April 24, 2013, 12:59 a.m. |
| Number Sequence — Part 3 | 100 | April 24, 2013, 12:43 a.m. |
| Number Sequence — Part 2 | 100 | April 24, 2013, 12:33 a.m. |
| Number Sequence | 100 | April 23, 2013, 11:56 p.m. |
| Beaver Code | 100 | April 23, 2013, 11:36 p.m. |
| Caesar Encryption | 100 | April 23, 2013, 9:14 p.m. |
| Original Caesar Cipher | 100 | April 23, 2013, 9:09 p.m. |
| Monoalphabetic Substitution | 100 | April 23, 2013, 9:04 p.m. |