| Recycled One-Time Pad | 100 | April 6, 2019, 10:55 a.m. |
| Modified Caesar Cipher | 100 | April 4, 2019, 10:33 p.m. |
| Number Sequence — Part 10 | 100 | April 4, 2019, 12:10 p.m. |
| Classical Ciphers^3 | 100 | April 3, 2019, 7:25 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 101 | March 31, 2019, 11:42 p.m. |
| Autokey Cipher | 101 | March 31, 2019, 11:23 p.m. |
| Playfair with hints about the grid | 100 | Feb. 21, 2018, 11:33 a.m. |
| Molehunt (Part 2/3) | 100 | Feb. 16, 2018, 5:08 p.m. |
| Molehunt (Part 1/3) | 100 | Feb. 16, 2018, 4:55 p.m. |
| ¿No Hablas Español? No problemo! | 100 | Feb. 16, 2018, 2:19 p.m. |
| Playfair Encryption | 100 | Feb. 15, 2018, 6:26 p.m. |
| Number Sequence — Part 7 | 100 | Feb. 15, 2018, 2:51 p.m. |
| The Einstein Enigma | 1,547 | Feb. 14, 2018, 11:36 p.m. |
| M-138 — Part 2 | 1,114 | Feb. 14, 2018, 8:56 p.m. |
| Advent-Challenge — Part 1 | 102 | Feb. 8, 2018, 12:33 p.m. |
| Number Sequence — Part 8 | 101 | Jan. 2, 2016, 5:05 p.m. |
| News from Castle Mansfeld | 102 | Jan. 2, 2016, 5 p.m. |
| A hidden word — Part 2 | 200 | April 16, 2015, 8:13 p.m. |
| M-138 — Part 1 | 105 | Jan. 14, 2015, 9:07 p.m. |
| ECDH-Key Exchange for Beginners | 100 | Oct. 13, 2014, 5:07 p.m. |
| Cracking SHA1-Hashed Passwords | 1,110 | Oct. 13, 2014, 1:19 a.m. |
| The Last Note | 105 | Oct. 12, 2014, 11:52 p.m. |
| Kaskade-S/T — Part 1 | 100 | March 17, 2014, 12:08 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 114 | March 12, 2014, 2:40 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 114 | March 12, 2014, 2:14 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 101 | March 12, 2014, 2:06 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 114 | March 12, 2014, 1:39 p.m. |
| Trifid Cipher | 120 | Nov. 2, 2013, 3:41 p.m. |
| Number Sequence — Part 5 | 100 | Oct. 26, 2013, 5:49 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 125 | Sept. 29, 2013, 6:53 p.m. |
| From Russia with Love | 120 | Sept. 9, 2013, 10:22 a.m. |
| Snow White and the seven dwarfs | 101 | Sept. 9, 2013, 9:46 a.m. |
| Nils away on travel | 108 | Aug. 20, 2013, 8:49 a.m. |
| A Secret Message from Castle Mansfeld | 100 | Aug. 19, 2013, 10:06 a.m. |
| A hidden word | 101 | May 20, 2013, 10:32 p.m. |
| Reserve Hand Procedure — Part 1 | 101 | May 20, 2013, 1:13 p.m. |
| ADFGVX — Part 1 | 100 | Nov. 16, 2012, 4:03 p.m. |
| Pigpen with a twist — Part 1 | 100 | Nov. 15, 2012, 12:35 p.m. |
| ADFGVX — Part 2 | 100 | Nov. 5, 2012, 5:43 p.m. |
| How do you become a big cryptographer? | 101 | Nov. 4, 2012, 6:58 p.m. |
| Letter to the Templars — Part 3 | 1,353 | Nov. 4, 2012, 3:46 a.m. |
| Beaver Code | 101 | Nov. 3, 2012, 12:13 p.m. |
| Letter to the Templars — Part 2 | 101 | Nov. 3, 2012, 11:27 a.m. |
| Letter to the Templars — Part 1 | 200 | July 16, 2012, 11:16 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | July 16, 2012, 1:47 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | July 16, 2012, 12:04 a.m. |
| Double Columnar Transposition | 100 | July 13, 2012, 1:08 p.m. |
| Monoalphabetic Substitution | 100 | July 13, 2012, 3:17 a.m. |
| Original Caesar Cipher | 100 | July 13, 2012, 2:50 a.m. |
| Caesar Encryption | 100 | July 13, 2012, 2:39 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | July 13, 2012, 2:19 a.m. |
| Grille Cipher | 100 | July 13, 2012, 2:08 a.m. |
| The Book Code: A Challenge for Bookworms | 101 | July 13, 2012, 1:27 a.m. |
| Factorization Cipher — Part 1 | 100 | July 12, 2012, 12:13 a.m. |
| Number Sequence — Part 2 | 100 | July 11, 2012, 11:11 p.m. |
| Number Sequence — Part 3 | 101 | July 11, 2012, 11:09 p.m. |
| Number Sequence | 100 | July 11, 2012, 11:06 p.m. |
| Number Sequence — Part 4 | 101 | July 11, 2012, 11:03 p.m. |