| Find the right route — Part 3 | 150 | Dec. 28, 2020, 8:37 a.m. |
| Find the right route — Part 2 | 200 | Dec. 19, 2020, 8:13 p.m. |
| Find the right route — Part 1 | 200 | Oct. 28, 2020, 8:56 a.m. |
| Lightweight Introduction to Lattices — Part 3 | 2,000 | July 16, 2020, 2:13 p.m. |
| Lightweight Introduction to Lattices — Part 2 | 200 | June 24, 2020, 9:52 a.m. |
| Polyhomophonic Substitution — Part 1 | 150 | March 23, 2020, 5:35 p.m. |
| A really long number sequence | 1,090 | Jan. 23, 2019, 12:25 p.m. |
| Cryptanalysis Hacking Puzzles — Part 1 | 101 | Jan. 13, 2019, 4:47 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 133 | Jan. 11, 2019, 5:15 p.m. |
| New Year's Greetings — Part 2 | 100 | Oct. 9, 2018, 3:50 p.m. |
| New Year's Greetings — Part 1 | 100 | Oct. 9, 2018, 3:37 p.m. |
| Autokey Cipher | 114 | Oct. 1, 2018, 4:30 p.m. |
| Modular Sequences | 114 | Oct. 1, 2018, 3:48 p.m. |
| Number Sequence — Part 10 | 150 | April 19, 2018, 11:07 p.m. |
| Advent-Challenge — Part 1 | 102 | Jan. 25, 2018, 5:41 p.m. |
| Number Sequence — Part 9 | 133 | Nov. 19, 2017, 5:22 p.m. |
| Number Sequence — Part 5 | 100 | March 15, 2017, 1:36 p.m. |
| Molehunt (Part 1/3) | 100 | Feb. 27, 2017, 11:02 p.m. |
| Number Sequence — Part 7 | 100 | Feb. 24, 2017, 5:17 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Jan. 22, 2017, 5:28 p.m. |
| ¿No Hablas Español? No problemo! | 100 | Jan. 22, 2017, 5:27 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Jan. 22, 2017, 5:21 p.m. |
| An 'unhearable' message | 100 | Jan. 18, 2017, 11:49 p.m. |
| The Last Note | 100 | Jan. 18, 2017, 12:48 a.m. |
| A Secret Message from Castle Mansfeld | 100 | Jan. 18, 2017, 12:04 a.m. |
| News from Castle Mansfeld | 100 | Jan. 17, 2017, 11:16 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | Jan. 15, 2017, 1:18 a.m. |
| An Invisible Message | 100 | Jan. 11, 2017, 9:24 p.m. |
| Hill Cipher with Sudoku Key | 100 | Jan. 8, 2017, 8:23 p.m. |
| Number Sequence — Part 6 | 100 | Jan. 8, 2017, 7:37 p.m. |
| RSA Factoring Challenge: RSA-220 | 0 | Jan. 2, 2017, 7:39 p.m. |
| RSA Factoring Challenge: RSA-704 | 0 | Jan. 2, 2017, 7:37 p.m. |
| RSA Factoring Challenge: RSA-210 | 0 | Jan. 2, 2017, 7:35 p.m. |
| Ku Klux Klan | 1,000 | Jan. 12, 2016, 9:24 p.m. |
| Recycled One-Time Pad | 100 | Jan. 7, 2016, 3:40 p.m. |
| A hidden word — Part 2 | 100 | Dec. 18, 2015, 1:26 p.m. |
| ADFGVX — Part 2 | 100 | Dec. 18, 2015, 12:57 p.m. |
| ADFGVX — Part 1 | 100 | Dec. 18, 2015, 11:34 a.m. |
| Image Noise | 104 | Dec. 15, 2015, 2:11 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Dec. 4, 2015, 4:53 p.m. |
| Snow White and the seven dwarfs | 100 | Dec. 1, 2015, 9:49 p.m. |
| Classical Ciphers^3 | 100 | Nov. 25, 2015, 8:52 p.m. |
| From Russia with Love | 100 | Nov. 22, 2015, 4:28 p.m. |
| Heartbleed — Part 1 | 100 | Nov. 3, 2015, 5:07 p.m. |
| Number Sequence — Part 8 | 102 | Nov. 3, 2015, 3:12 p.m. |
| Nils away on travel | 100 | Nov. 1, 2015, 9:19 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | Nov. 1, 2015, 5:59 p.m. |
| Modified Caesar Cipher | 100 | Nov. 1, 2015, 5:26 p.m. |
| Playfair with hints about the grid | 100 | Nov. 1, 2015, 4:06 p.m. |
| M-138 — Part 1 | 100 | Oct. 31, 2015, 7:47 p.m. |
| How do you become a big cryptographer? | 100 | Oct. 31, 2015, 6:44 p.m. |
| Pigpen with a twist — Part 1 | 100 | Oct. 30, 2015, 4:52 p.m. |
| Monoalphabetic Substitution | 100 | Oct. 30, 2015, 3:13 p.m. |
| Number Sequence — Part 4 | 100 | Oct. 29, 2015, 1:36 p.m. |
| Number Sequence — Part 3 | 100 | Oct. 29, 2015, 1:31 p.m. |
| ECDH-Key Exchange for Beginners | 100 | Oct. 26, 2015, 12:49 p.m. |
| Number Sequence — Part 2 | 100 | Oct. 26, 2015, 9:43 a.m. |
| The Book Code: A Challenge for Bookworms | 100 | Oct. 25, 2015, 3:21 p.m. |
| A hidden word | 100 | Oct. 25, 2015, 11:39 a.m. |
| Caesar Encryption | 100 | Oct. 25, 2015, 11:37 a.m. |
| Cracking SHA1-Hashed Passwords | 1,103 | Oct. 25, 2015, 11:11 a.m. |
| Number Sequence | 100 | Oct. 25, 2015, 12:29 a.m. |
| Trifid Cipher | 100 | Oct. 24, 2015, 8:23 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | Oct. 24, 2015, 3:25 p.m. |
| One-Time Pad with Flaws | 100 | Oct. 24, 2015, 1:55 p.m. |
| Grille Cipher | 100 | Oct. 24, 2015, 12:22 p.m. |
| Factorization Cipher — Part 1 | 100 | Oct. 24, 2015, 11:22 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Oct. 24, 2015, 11:06 a.m. |
| Original Caesar Cipher | 100 | Oct. 21, 2015, 1:23 p.m. |
| Letter to the Templars — Part 3 | 1,115 | Oct. 21, 2015, 1:03 p.m. |
| Letter to the Templars — Part 2 | 100 | Oct. 21, 2015, 12:39 p.m. |
| Letter to the Templars — Part 1 | 100 | Oct. 21, 2015, 12:23 p.m. |
| Beaver Code | 100 | Oct. 21, 2015, 11:10 a.m. |
Gold1
Silver2
Bronze1
