| The T52 Sturgeon Challenge — Part 2 | 1,127 | Aug. 25, 2021, 9:11 p.m. |
| The T52 Sturgeon Challenge — Part 1 | 1,127 | Aug. 19, 2021, 10:35 p.m. |
| The SZ42 Challenge — Part 9 | 1,183 | July 25, 2021, 1:03 p.m. |
| The SZ42 Challenge — Part 8 | 1,172 | July 24, 2021, 6:20 p.m. |
| The SZ42 Challenge — Part 7 | 1,172 | July 23, 2021, 7:05 p.m. |
| The SZ42 Challenge — Part 6 | 1,168 | July 17, 2021, 11:08 p.m. |
| The SZ42 Challenge — Part 5 | 1,164 | July 16, 2021, 9:53 p.m. |
| The SZ42 Challenge — Part 4 | 1,163 | July 16, 2021, 9:23 p.m. |
| The SZ42 Challenge — Part 3 | 1,162 | July 14, 2021, 1:29 p.m. |
| The SZ42 Challenge — Part 2 | 1,160 | July 14, 2021, 12:02 p.m. |
| The SZ42 Challenge — Part 1 | 1,158 | July 13, 2021, 4:40 p.m. |
| Homophonic Encryption — Part 4 | 1,127 | June 29, 2021, 10:57 a.m. |
| Homophonic Encryption — Part 3 | 1,127 | June 28, 2021, 11:51 p.m. |
| Homophonic Encryption — Part 2 | 1,127 | June 28, 2021, 11:18 p.m. |
| Homophonic Encryption — Part 1 | 1,126 | June 28, 2021, 8:28 p.m. |
| Advent Challenge — Part 4 | 1,116 | Nov. 20, 2020, 11 a.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,085 | Nov. 13, 2020, 6:43 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Nov. 8, 2020, 10:19 p.m. |
| Ku Klux Klan | 1,000 | Feb. 4, 2019, 12:42 p.m. |
| Enigma Part 1 | 1,087 | Jan. 12, 2019, 9:32 a.m. |
| Summer Job | 1,184 | Jan. 11, 2019, 10:59 a.m. |
| Nils away on travel | 100 | Jan. 7, 2019, 7:06 p.m. |
| Double Columnar Transposition | 100 | Jan. 7, 2019, 1:34 p.m. |
| M-138 — Part 3 | 1,106 | Jan. 6, 2019, 12:06 p.m. |
| The Einstein Enigma | 1,162 | Jan. 5, 2019, 4:04 p.m. |
| Advent Challenge — Part 3 | 1,156 | Jan. 3, 2019, 8:45 p.m. |
| Advent-Challenge — Part 2 | 1,155 | Jan. 2, 2019, 12:17 p.m. |
| Zodiac Cipher | 100 | Dec. 29, 2018, 2:12 p.m. |
| Advent-Challenge — Part 1 | 100 | Dec. 20, 2018, 4:06 p.m. |
| Number Sequence — Part 9 | 100 | Dec. 17, 2018, 9:01 p.m. |
| Autokey Cipher | 101 | Dec. 17, 2018, 7:42 p.m. |
| Number Sequence — Part 10 | 100 | Dec. 17, 2018, 7:05 p.m. |
| Molehunt (Part 3/3) | 1,088 | Dec. 17, 2018, 1:59 p.m. |
| Molehunt (Part 2/3) | 100 | Dec. 16, 2018, 11:27 a.m. |
| Molehunt (Part 1/3) | 100 | Dec. 15, 2018, 4:53 p.m. |
| Enigma Messages | 100 | Jan. 24, 2017, 11:52 a.m. |
| Number Sequence — Part 5 | 100 | Jan. 24, 2017, 11 a.m. |
| Heartbleed — Part 2 | 100 | Jan. 12, 2017, 5:29 p.m. |
| Heartbleed — Part 1 | 100 | Jan. 12, 2017, 2:26 p.m. |
| Playfair with hints about the grid | 100 | Jan. 9, 2017, 3:02 p.m. |
| Playfair Encryption | 100 | Jan. 9, 2017, 2:52 p.m. |
| Hill Cipher with Sudoku Key | 100 | Jan. 9, 2017, 12:08 p.m. |
| Beaver Code | 100 | Jan. 9, 2017, 9:47 a.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,094 | Jan. 8, 2017, 1:32 p.m. |
| Cascading Encryption — Part 1/3 | 100 | Jan. 7, 2017, 7:59 p.m. |
| Number Sequence — Part 6 | 100 | Dec. 13, 2016, 9:48 p.m. |
| The Last Note | 100 | Dec. 12, 2016, 3:10 p.m. |
| From Russia with Love | 100 | Dec. 6, 2016, 11:06 a.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | Dec. 3, 2016, 5:01 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | Dec. 3, 2016, 4:26 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | Dec. 3, 2016, 4:12 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | Dec. 3, 2016, 4:05 p.m. |
| How do you become a big cryptographer? | 100 | Nov. 30, 2016, 9:40 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | Nov. 29, 2016, 9:55 p.m. |
| News from Castle Mansfeld | 100 | Nov. 29, 2016, 7:16 p.m. |
| Image Noise | 100 | Nov. 27, 2016, 3:22 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | Nov. 26, 2016, 10:20 p.m. |
| A hidden word | 100 | Nov. 23, 2016, 12:02 p.m. |
| A hidden word — Part 2 | 100 | Nov. 23, 2016, 10:17 a.m. |
| M-138 — Part 2 | 1,131 | Nov. 22, 2016, 5:31 p.m. |
| M-138 — Part 1 | 100 | Nov. 21, 2016, 10:42 p.m. |
| Number Sequence — Part 8 | 100 | Nov. 21, 2016, 9:09 p.m. |
| Multilingual Monoalphabetic Substitution | 100 | Nov. 21, 2016, 6:15 p.m. |
| Letter to the Templars — Part 3 | 1,106 | Nov. 21, 2016, 2:13 p.m. |
| Letter to the Templars — Part 2 | 100 | Nov. 21, 2016, 1:57 p.m. |
| Letter to the Templars — Part 1 | 100 | Nov. 21, 2016, 1:02 p.m. |
| ¿No Hablas Español? No problemo! | 100 | Nov. 21, 2016, 12:01 p.m. |
| ADFGVX — Part 2 | 100 | Nov. 20, 2016, 1:11 p.m. |
| ADFGVX — Part 1 | 100 | Nov. 19, 2016, 8:24 p.m. |
| Hybrid Encryption I | 1,136 | June 29, 2012, 1:47 p.m. |
| Alice's Birthday Party (Part 1) | 1,135 | June 28, 2012, 3:33 p.m. |
| RSA: Two different keys — same ciphertext | 1,164 | June 28, 2012, 12:05 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,160 | June 28, 2012, 9:06 a.m. |
| Alice's Birthday Party (Part 2) | 1,135 | June 27, 2012, 1:37 p.m. |
| Cracking SHA1-Hashed Passwords | 1,149 | June 19, 2012, 11:54 a.m. |
| Kaskade-S/T — Part 1 | 100 | June 19, 2012, 8:57 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | June 15, 2012, 3:16 p.m. |
| A Secret Message from Castle Mansfeld | 100 | June 12, 2012, 11:28 a.m. |
| Grille Cipher | 100 | June 11, 2012, 3:42 p.m. |
| Factorization Cipher — Part 1 | 100 | June 11, 2012, 1:28 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | June 11, 2012, 12:52 p.m. |
| One-Time Pad with Flaws | 100 | June 11, 2012, 10:48 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | June 8, 2012, 11:37 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | June 8, 2012, 9:43 a.m. |
| Monoalphabetic Substitution | 100 | June 5, 2012, 11:13 a.m. |
| Number Sequence — Part 4 | 102 | June 4, 2012, 8:37 p.m. |
| Number Sequence — Part 3 | 102 | June 4, 2012, 8:33 p.m. |
| Modified Caesar Cipher | 100 | June 2, 2012, 10:24 p.m. |
| Number Sequence — Part 2 | 100 | June 2, 2012, 3:06 p.m. |
| Number Sequence | 100 | June 2, 2012, 3 p.m. |
| Caesar Encryption | 100 | June 2, 2012, 11:39 a.m. |
| Original Caesar Cipher | 100 | June 2, 2012, 10:54 a.m. |