| Find the right route — Part 1 | 105 | Nov. 16, 2020, 6:04 p.m. |
| Polyhomophonic Substitution — Part 1 | 117 | March 27, 2020, 2:06 p.m. |
| Hill Cipher with Sudoku Key | 100 | March 22, 2019, 4:56 p.m. |
| Number Sequence — Part 10 | 100 | March 22, 2019, 3:59 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 101 | March 22, 2019, 2:48 p.m. |
| Advent-Challenge — Part 1 | 100 | Nov. 23, 2018, 10:20 a.m. |
| Modular Sequences | 102 | Nov. 22, 2018, 2:48 p.m. |
| Molehunt (Part 2/3) | 100 | Sept. 28, 2018, 5:06 p.m. |
| Molehunt (Part 1/3) | 100 | Sept. 28, 2018, 4:17 p.m. |
| Autokey Cipher | 125 | Sept. 28, 2018, 3:52 p.m. |
| Number Sequence — Part 9 | 101 | March 25, 2018, 1:20 p.m. |
| A really long number sequence | 1,104 | Dec. 20, 2015, 5:01 p.m. |
| Pigpen with a twist — Part 2 | 1,105 | Dec. 1, 2015, 6:20 p.m. |
| Pigpen with a twist — Part 3 | 1,105 | Nov. 18, 2015, 6:15 a.m. |
| Concealed Messages — Vigenère's Night Sky | 1,110 | Nov. 15, 2015, 11:52 a.m. |
| Pigpen with a twist — Part 1 | 100 | Oct. 23, 2015, 6:24 a.m. |
| Reserve Hand Procedure — Part 1 | 100 | Oct. 22, 2015, 5:06 p.m. |
| Recycled One-Time Pad | 100 | Oct. 22, 2015, 2:55 p.m. |
| Heartbleed — Part 3 | 1,151 | Oct. 21, 2015, 5:23 a.m. |
| Cracking SHA1-Hashed Passwords | 1,103 | Oct. 15, 2015, 7:02 a.m. |
| Classical Ciphers^3 | 100 | Oct. 12, 2015, 5:22 p.m. |
| A Secret Message from Castle Mansfeld | 100 | Oct. 12, 2015, 9:08 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Oct. 11, 2015, 8:06 p.m. |
| Strange Message from Thessaloniki | 100 | Oct. 11, 2015, 6:29 p.m. |
| From Russia with Love | 100 | Oct. 11, 2015, 8:51 a.m. |
| The Last Note | 100 | Oct. 9, 2015, 8:54 a.m. |
| One-Time Pad with Flaws | 100 | Oct. 7, 2015, 11:59 a.m. |
| Ku Klux Klan | 1,000 | Oct. 6, 2015, 7:10 p.m. |
| Alice's Birthday Party (Part 2) | 1,100 | Oct. 4, 2015, 5:52 p.m. |
| Alice's Birthday Party (Part 1) | 1,100 | Oct. 4, 2015, 5:09 p.m. |
| Heartbleed — Part 2 | 100 | Oct. 3, 2015, 1:05 p.m. |
| Heartbleed — Part 1 | 100 | Oct. 3, 2015, 1:02 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Oct. 3, 2015, 7:08 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Oct. 3, 2015, 6:37 a.m. |
| Weakened Granit — Part 1 | 111 | Oct. 2, 2015, 7:32 p.m. |
| The Book Code: A Challenge for Bookworms | 100 | Sept. 30, 2015, 9:25 a.m. |
| An 'unhearable' message | 100 | Sept. 29, 2015, 10:27 a.m. |
| Modified Caesar Cipher | 100 | Sept. 19, 2015, 6:05 p.m. |
| Factorization Cipher — Part 3 | 1,109 | Sept. 18, 2015, 4:31 p.m. |
| Snow White and the seven dwarfs | 100 | Sept. 18, 2015, 5:27 a.m. |
| Grille Cipher | 100 | Sept. 18, 2015, 5:03 a.m. |
| A hidden word — Part 2 | 101 | Sept. 17, 2015, 12:35 p.m. |
| Factorization Cipher — Part 2 | 1,108 | Sept. 15, 2015, 11:55 a.m. |
| Number Sequence — Part 8 | 200 | Sept. 14, 2015, 1:54 p.m. |
| Factorization Cipher — Part 1 | 100 | Sept. 14, 2015, 1:50 p.m. |
| How do you become a big cryptographer? | 100 | Sept. 14, 2015, 8:33 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Sept. 14, 2015, 6:17 a.m. |
| Monoalphabetic Substitution | 100 | Sept. 13, 2015, 12:31 p.m. |
| Letter to the Templars — Part 3 | 1,116 | Sept. 13, 2015, 8:39 a.m. |
| Letter to the Templars — Part 2 | 100 | Sept. 13, 2015, 8:02 a.m. |
| Letter to the Templars — Part 1 | 100 | Sept. 13, 2015, 7:51 a.m. |
| Beaver Code | 100 | Sept. 13, 2015, 6:51 a.m. |
| A hidden word | 100 | Sept. 12, 2015, 1:01 p.m. |
| Number Sequence — Part 7 | 101 | Sept. 12, 2015, 12:48 p.m. |
| Number Sequence — Part 5 | 100 | Sept. 7, 2015, 5:55 p.m. |
| Number Sequence — Part 6 | 101 | Sept. 5, 2015, 6:29 a.m. |
| Number Sequence — Part 4 | 100 | Aug. 27, 2015, 3:17 p.m. |
| Number Sequence — Part 3 | 100 | Aug. 27, 2015, 3:08 p.m. |
| Number Sequence — Part 2 | 100 | Aug. 27, 2015, 2:53 p.m. |
| Caesar Encryption | 100 | Aug. 27, 2015, 8:16 a.m. |
| Original Caesar Cipher | 100 | Aug. 27, 2015, 7:33 a.m. |
| Number Sequence | 100 | June 22, 2012, 3:49 p.m. |