| The Book Code: A Challenge for Bookworms | 100 | March 10, 2019, 11:54 p.m. |
| RSA: Two different keys — same ciphertext | 1,089 | March 10, 2019, 11:32 p.m. |
| Pigpen with a twist — Part 1 | 100 | March 10, 2019, 9 p.m. |
| Nils away on travel | 100 | March 10, 2019, 7:55 p.m. |
| Hybrid Encryption I | 1,087 | March 10, 2019, 7:45 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | March 10, 2019, 1:40 a.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,087 | March 9, 2019, 10:38 p.m. |
| Classical Ciphers^3 | 100 | March 8, 2019, 9:04 p.m. |
| M-138 — Part 1 | 100 | March 8, 2019, 2:10 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,087 | March 8, 2019, 5:49 a.m. |
| Broadcasting and low exponent — RSA Attack | 1,089 | March 8, 2019, 3 a.m. |
| Alice's Birthday Party (Part 2) | 1,087 | March 8, 2019, 2:48 a.m. |
| Modified Caesar Cipher | 100 | March 8, 2019, 12:25 a.m. |
| Alice's Birthday Party (Part 1) | 1,087 | Feb. 25, 2019, 1:19 a.m. |
| Reserve Hand Procedure — Part 1 | 100 | Feb. 23, 2019, 5:11 p.m. |
| How do you become a big cryptographer? | 100 | Feb. 23, 2019, 2:59 p.m. |
| Number Sequence — Part 8 | 100 | Feb. 23, 2019, 2:22 p.m. |
| From Russia with Love | 100 | Feb. 23, 2019, 5:42 a.m. |
| Snow White and the seven dwarfs | 100 | Feb. 23, 2019, 5:06 a.m. |
| Advent-Challenge — Part 1 | 100 | Feb. 23, 2019, 4:51 a.m. |
| One-Time Pad with Flaws | 100 | Feb. 17, 2019, 3:52 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Feb. 17, 2019, 2:57 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Feb. 17, 2019, 2:51 a.m. |
| Cracking SHA1-Hashed Passwords | 1,088 | Feb. 17, 2019, 2:42 a.m. |
| Grille Cipher | 100 | Feb. 17, 2019, 2:37 a.m. |
| Factorization Cipher — Part 1 | 100 | Feb. 17, 2019, 2:20 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Feb. 17, 2019, 2:06 a.m. |
| Letter to the Templars — Part 3 | 1,094 | Feb. 17, 2019, 1:55 a.m. |
| Monoalphabetic Substitution | 100 | Feb. 17, 2019, 1:43 a.m. |
| A hidden word | 100 | Feb. 17, 2019, 1:15 a.m. |
| Number Sequence — Part 4 | 100 | Feb. 17, 2019, 1:10 a.m. |
| Letter to the Templars — Part 2 | 100 | Feb. 17, 2019, 1:05 a.m. |
| Number Sequence — Part 3 | 100 | Feb. 17, 2019, 12:57 a.m. |
| Letter to the Templars — Part 1 | 100 | Feb. 17, 2019, 12:54 a.m. |
| Beaver Code | 100 | Feb. 16, 2019, 11:50 p.m. |
| Caesar Encryption | 100 | Feb. 16, 2019, 11:39 p.m. |
| Number Sequence — Part 2 | 100 | Feb. 16, 2019, 11:27 p.m. |
| Original Caesar Cipher | 100 | Feb. 16, 2019, 11:23 p.m. |
| Number Sequence | 100 | Feb. 16, 2019, 11:17 p.m. |