| Find the right route — Part 2 | 100 | Oct. 21, 2022, 4:14 p.m. |
| Find the right route — Part 1 | 100 | Oct. 20, 2022, 5:19 p.m. |
| Double Columnar Transposition | 100 | Sept. 27, 2020, 2:30 p.m. |
| Hill Cipher with Sudoku Key | 100 | Sept. 26, 2020, 4:57 p.m. |
| Playfair with hints about the grid | 100 | Sept. 25, 2020, 1:02 a.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,083 | Sept. 24, 2020, 1:25 a.m. |
| Factorization Cipher — Part 3 | 1,086 | Sept. 17, 2020, 3:40 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | Oct. 13, 2019, 11:22 a.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Oct. 10, 2019, 11:20 a.m. |
| ECDH-Key Exchange for Beginners | 100 | Oct. 10, 2019, 11:05 a.m. |
| A hidden word — Part 2 | 100 | Oct. 9, 2019, 5:34 p.m. |
| Autokey Cipher | 100 | Sept. 16, 2019, 7:19 p.m. |
| Kaskade-S/T — Part 2 | 1,087 | Sept. 7, 2019, 7:26 p.m. |
| Kaskade-S/T — Part 1 | 100 | Sept. 7, 2019, 1:38 a.m. |
| Playfair Encryption | 100 | Aug. 11, 2018, 12:34 a.m. |
| Heartbleed — Part 2 | 100 | Aug. 9, 2018, 3:05 p.m. |
| Heartbleed — Part 1 | 100 | Aug. 9, 2018, 2:58 p.m. |
| Number Sequence — Part 10 | 101 | Aug. 6, 2018, 2:48 p.m. |
| Number Sequence — Part 9 | 100 | Aug. 6, 2018, 2:30 p.m. |
| A really long number sequence | 1,092 | Aug. 6, 2018, 2:19 p.m. |
| Factorization Cipher — Part 2 | 1,092 | Aug. 4, 2018, 1:36 a.m. |
| The Last Note | 100 | Aug. 3, 2018, 12:52 p.m. |
| Image Noise | 100 | Aug. 2, 2018, 11:53 p.m. |
| Hybrid Encryption I | 1,089 | Aug. 2, 2018, 2:51 p.m. |
| Trifid Cipher | 100 | July 31, 2018, 4:51 p.m. |
| ¿No Hablas Español? No problemo! | 100 | July 31, 2018, 3:46 p.m. |
| A Secret Message from Castle Mansfeld | 100 | July 29, 2018, 8:41 p.m. |
| Enigma Part 1 | 1,089 | July 27, 2018, 3:52 p.m. |
| Molehunt (Part 2/3) | 100 | July 27, 2018, 2:36 p.m. |
| Molehunt (Part 1/3) | 100 | July 27, 2018, 1:48 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | July 26, 2018, 11:33 a.m. |
| How do you become a big cryptographer? | 100 | July 25, 2018, 4:52 p.m. |
| The Book Code: A Challenge for Bookworms | 100 | March 17, 2018, 12:19 a.m. |
| Advent-Challenge — Part 1 | 101 | March 5, 2018, 4:38 p.m. |
| Number Sequence — Part 6 | 100 | March 4, 2018, 9:17 p.m. |
| Number Sequence — Part 8 | 100 | March 4, 2018, 9:11 p.m. |
| Classical Ciphers^3 | 100 | March 3, 2018, 9:26 a.m. |
| Pigpen with a twist — Part 1 | 100 | Nov. 25, 2017, 12:27 a.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,092 | Sept. 16, 2017, 6:13 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,095 | Sept. 16, 2017, 2:52 p.m. |
| Alice's Birthday Party (Part 2) | 1,092 | Sept. 16, 2017, 2:40 p.m. |
| Alice's Birthday Party (Part 1) | 1,092 | Sept. 15, 2017, 9:26 p.m. |
| ADFGVX — Part 1 | 100 | April 22, 2017, 11:40 p.m. |
| ADFGVX — Part 2 | 100 | April 22, 2017, 2:37 p.m. |
| Nils away on travel | 100 | April 21, 2017, 7:33 p.m. |
| From Russia with Love | 100 | Jan. 28, 2017, 12:25 a.m. |
| M-138 — Part 2 | 1,128 | Jan. 21, 2017, 8:38 a.m. |
| M-138 — Part 1 | 100 | Jan. 14, 2017, 11:07 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Dec. 10, 2016, 12:12 a.m. |
| Reserve Hand Procedure — Part 1 | 100 | Dec. 10, 2016, 12:10 a.m. |
| Snow White and the seven dwarfs | 100 | Nov. 20, 2016, 4:03 p.m. |
| One-Time Pad with Flaws | 100 | Nov. 20, 2016, 3:27 p.m. |
| Monoalphabetic Substitution | 100 | Nov. 20, 2016, 2:02 p.m. |
| Cracking SHA1-Hashed Passwords | 1,097 | Nov. 20, 2016, 11:11 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Nov. 15, 2016, 1:54 p.m. |
| Modified Caesar Cipher | 100 | Nov. 11, 2016, 4:41 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Nov. 11, 2016, 3:37 p.m. |
| Number Sequence — Part 4 | 100 | Nov. 11, 2016, 3:35 p.m. |
| Number Sequence — Part 3 | 100 | Nov. 11, 2016, 3:34 p.m. |
| Caesar Encryption | 100 | Oct. 29, 2016, 11:19 a.m. |
| Original Caesar Cipher | 100 | Oct. 29, 2016, 11:04 a.m. |
| Number Sequence — Part 2 | 100 | Oct. 25, 2016, 2:58 p.m. |
| Grille Cipher | 100 | Oct. 13, 2016, 1:19 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Oct. 11, 2016, 2:47 p.m. |
| Factorization Cipher — Part 1 | 100 | Oct. 11, 2016, 2:36 p.m. |
| A hidden word | 100 | Oct. 10, 2016, 4:30 p.m. |
| Letter to the Templars — Part 3 | 1,106 | Oct. 10, 2016, 4:26 p.m. |
| Letter to the Templars — Part 2 | 100 | Oct. 10, 2016, 4:17 p.m. |
| Letter to the Templars — Part 1 | 100 | Oct. 10, 2016, 4:11 p.m. |
| Number Sequence | 100 | Oct. 10, 2016, 3:45 p.m. |
| Beaver Code | 100 | Oct. 10, 2016, 3:44 p.m. |