| RSA: Two different keys — same ciphertext | 1,088 | July 16, 2019, 10:31 a.m. |
| Pigpen with a twist — Part 1 | 100 | July 16, 2019, 6:51 a.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | July 14, 2019, 11:04 a.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,086 | July 12, 2019, 7:58 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | July 12, 2019, 1:14 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,088 | July 11, 2019, 6:17 p.m. |
| How do you become a big cryptographer? | 100 | July 11, 2019, 4:43 p.m. |
| Alice's Birthday Party (Part 2) | 1,086 | July 11, 2019, 1:49 p.m. |
| Alice's Birthday Party (Part 1) | 1,086 | July 9, 2019, 7:22 p.m. |
| Advent-Challenge — Part 1 | 100 | July 5, 2019, 8:09 p.m. |
| Cracking SHA1-Hashed Passwords | 1,087 | July 1, 2019, 11:39 a.m. |
| Factorization Cipher — Part 1 | 100 | July 1, 2019, 7:55 a.m. |
| Letter to the Templars — Part 3 | 1,092 | June 30, 2019, 9:39 a.m. |
| Letter to the Templars — Part 2 | 100 | June 29, 2019, 5:49 p.m. |
| Letter to the Templars — Part 1 | 100 | June 29, 2019, 4:40 p.m. |
| Beaver Code | 100 | June 29, 2019, 11:21 a.m. |