| Homophonic Encryption — Part 1 | 1,261 | July 9, 2019, 3:30 p.m. |
| Monoalphabetic Substitution with Nostradamus Flavor | 1,223 | June 7, 2019, 10:57 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 101 | May 28, 2019, 10:20 p.m. |
| Cryptanalysis Hacking Puzzles — Part 1 | 100 | May 28, 2019, 3:38 p.m. |
| Autokey Cipher | 100 | May 23, 2019, 7:57 p.m. |
| Advent Challenge — Part 4 | 1,178 | Aug. 18, 2018, 6:12 p.m. |
| Advent-Challenge — Part 2 | 1,177 | Aug. 16, 2018, 11:28 p.m. |
| Summer Job | 1,278 | Aug. 5, 2018, 5:41 p.m. |
| The Einstein Enigma | 1,197 | July 27, 2018, 7:49 p.m. |
| Number Sequence — Part 10 | 101 | July 27, 2018, 3:41 p.m. |
| Advent-Challenge — Part 1 | 100 | July 27, 2018, 2:02 p.m. |
| Heartbleed — Part 2 | 100 | March 9, 2017, 8:34 p.m. |
| Heartbleed — Part 1 | 100 | March 8, 2017, 8:08 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,093 | March 8, 2017, 1:59 p.m. |
| Double Column Transposition — Part 1 | 1,116 | March 8, 2017, 12:49 a.m. |
| Hybrid Encryption I | 1,094 | March 2, 2017, 6:15 p.m. |
| Cracking SHA1-Hashed Passwords | 1,096 | Feb. 28, 2017, 9:18 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,097 | Feb. 26, 2017, 12:56 a.m. |
| Alice's Birthday Party (Part 2) | 1,094 | Feb. 25, 2017, 7:40 p.m. |
| Alice's Birthday Party (Part 1) | 1,094 | Feb. 18, 2017, 12:09 a.m. |
| Zodiac Cipher | 100 | May 19, 2016, 2:17 p.m. |
| New Year's Greetings — Part 4 | 103 | April 24, 2016, 1:29 p.m. |
| New Year's Greetings — Part 3 | 103 | April 23, 2016, 11:11 p.m. |
| New Year's Greetings — Part 2 | 103 | April 23, 2016, 10:57 p.m. |
| New Year's Greetings — Part 1 | 103 | April 23, 2016, 10:36 p.m. |
| Double Columnar Transposition | 100 | Jan. 20, 2016, 2:44 p.m. |
| Number Sequence — Part 8 | 101 | Jan. 16, 2016, 4:10 p.m. |
| Image Noise | 102 | Jan. 16, 2016, 3:20 p.m. |
| News from Castle Mansfeld | 102 | Jan. 4, 2016, 6:37 p.m. |
| BCR code (Book-Caesar-RSA) | 1,114 | Nov. 9, 2015, 8:16 p.m. |
| Weakened Granit — Part 1 | 102 | Nov. 7, 2015, 9:32 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,100 | Oct. 23, 2015, 10:42 p.m. |
| Number Sequence — Part 6 | 101 | Aug. 14, 2015, 8:30 p.m. |
| Recycled One-Time Pad | 100 | Aug. 11, 2015, 2:52 p.m. |
| Playfair Encryption | 100 | July 16, 2015, 3:05 p.m. |
| Strange Message from Thessaloniki | 100 | July 16, 2015, 2:07 p.m. |
| Playfair with hints about the grid | 100 | July 12, 2015, 6:21 p.m. |
| Enigma Messages | 100 | July 8, 2015, 10:53 p.m. |
| Hill Cipher with Sudoku Key | 100 | July 8, 2015, 4:50 p.m. |
| Pigpen with a twist — Part 2 | 1,108 | June 24, 2015, 8:03 p.m. |
| Multilingual Monoalphabetic Substitution | 100 | June 2, 2015, 5:04 p.m. |
| Trifid Cipher | 100 | April 21, 2015, 9:26 a.m. |
| A hidden word — Part 2 | 125 | April 19, 2015, 7:26 p.m. |
| Turing Bombe Enigma I | 100 | April 16, 2015, 11:40 p.m. |
| Enigma Part 2 | 1,103 | April 10, 2015, 1:34 a.m. |
| Enigma Part 1 | 1,103 | April 5, 2015, 10:13 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | April 4, 2015, 10:12 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | April 4, 2015, 10:05 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | April 3, 2015, 4:20 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | April 2, 2015, 10:45 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | March 30, 2015, 8:17 p.m. |
| Number Sequence — Part 3 | 100 | Feb. 13, 2015, 9:43 p.m. |
| M-138 — Part 3 | 1,286 | Feb. 11, 2015, 9:29 a.m. |
| Factorization Cipher — Part 3 | 1,115 | Jan. 19, 2015, 3:40 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,114 | Jan. 16, 2015, 5:07 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Jan. 12, 2015, 9:13 p.m. |
| From Russia with Love | 100 | Jan. 12, 2015, midnight |
| M-138 — Part 2 | 1,406 | Jan. 9, 2015, 11:42 p.m. |
| M-138 — Part 1 | 106 | Jan. 8, 2015, 10:59 a.m. |
| ¿No Hablas Español? No problemo! | 100 | Jan. 7, 2015, 11:27 p.m. |
| Nils away on travel | 100 | Jan. 7, 2015, 11 p.m. |
| The Last Note | 101 | Jan. 7, 2015, 10:19 p.m. |
| Molehunt (Part 2/3) | 100 | Aug. 28, 2013, 9:24 p.m. |
| Molehunt (Part 1/3) | 100 | Aug. 28, 2013, 8:50 p.m. |
| The Book Code: A Challenge for Bookworms | 100 | Aug. 5, 2013, 8:30 p.m. |
| Cascading Encryption — Part 1/3 | 101 | July 19, 2013, 12:52 p.m. |
| Reserve Hand Procedure — Part 1 | 101 | July 16, 2013, 10:44 a.m. |
| ADFGVX — Part 2 | 100 | July 7, 2013, 7:50 p.m. |
| ADFGVX — Part 1 | 100 | July 7, 2013, 6:32 p.m. |
| An 'unhearable' message | 100 | June 6, 2013, 6:15 p.m. |
| Snow White and the seven dwarfs | 102 | June 2, 2013, 3:31 p.m. |
| Pigpen with a twist — Part 1 | 100 | May 29, 2013, 10:33 p.m. |
| Factorization Cipher — Part 2 | 1,140 | May 27, 2013, 11:37 p.m. |
| A Secret Message from Castle Mansfeld | 100 | April 29, 2013, 10:14 p.m. |
| An Invisible Message | 100 | April 29, 2013, 4:47 p.m. |
| Number Sequence — Part 4 | 100 | April 26, 2013, 7:56 a.m. |
| Music Code — Part 2 | 1,131 | April 9, 2013, 10:58 p.m. |
| Music Code — Part 1 | 100 | April 4, 2013, 10:59 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | April 4, 2013, 7:06 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | April 4, 2013, 5:49 p.m. |
| Modified Caesar Cipher | 100 | April 3, 2013, 6:42 p.m. |
| Classical Ciphers^3 | 100 | April 3, 2013, 10:36 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | March 27, 2013, 10:27 p.m. |
| How do you become a big cryptographer? | 100 | March 24, 2013, 1:15 a.m. |
| Grille Cipher | 100 | March 23, 2013, 11:10 p.m. |
| One-Time Pad with Flaws | 100 | March 21, 2013, 9:31 p.m. |
| Factorization Cipher — Part 1 | 100 | March 19, 2013, 10:41 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | March 16, 2013, 11:34 p.m. |
| Beaver Code | 100 | March 16, 2013, 10:46 p.m. |
| Number Sequence | 100 | March 16, 2013, 8:06 p.m. |
| Letter to the Templars — Part 3 | 1,201 | March 15, 2013, 7:02 p.m. |
| Letter to the Templars — Part 2 | 100 | March 15, 2013, 6:18 p.m. |
| Letter to the Templars — Part 1 | 100 | March 15, 2013, 5:53 p.m. |
| A hidden word | 101 | March 15, 2013, 1:16 p.m. |
| Caesar Encryption | 100 | March 15, 2013, 12:57 p.m. |
| Monoalphabetic Substitution | 100 | March 13, 2013, 11:05 p.m. |
| Number Sequence — Part 2 | 100 | March 13, 2013, 8:49 p.m. |
| Original Caesar Cipher | 100 | March 13, 2013, 8:35 p.m. |