| Polyhomophonic Substitution — Part 2 | 1,117 | Feb. 5, 2023, 2:05 p.m. |
| Polyhomophonic Substitution — Part 1 | 100 | Feb. 3, 2023, 7:31 p.m. |
| Modular Sequences | 100 | Feb. 2, 2023, 4:48 p.m. |
| Lightweight Introduction to Lattices — Part 3 | 1,121 | Feb. 1, 2023, 12:19 a.m. |
| Lightweight Introduction to Lattices — Part 2 | 100 | Jan. 30, 2023, 10:35 p.m. |
| Lightweight Introduction to Lattices — Part 1 | 100 | Jan. 30, 2023, 8:18 p.m. |
| Find the right route — Part 3 | 100 | Jan. 19, 2023, 5:28 p.m. |
| Find the right route — Part 2 | 100 | Jan. 18, 2023, 11:29 a.m. |
| Find the right route — Part 1 | 100 | Jan. 17, 2023, 9:12 p.m. |
| Strange Message from Thessaloniki | 100 | Jan. 13, 2023, 3:49 p.m. |
| Summer Job | 1,185 | Jan. 8, 2019, 8:51 a.m. |
| Autokey Cipher | 101 | Jan. 7, 2019, 10:50 a.m. |
| Music Code — Part 1 | 100 | April 18, 2018, 10:04 p.m. |
| Music Code — Part 2 | 1,092 | April 18, 2018, 9:50 p.m. |
| Recycled One-Time Pad | 100 | April 17, 2018, 8:32 a.m. |
| The Einstein Enigma | 1,264 | April 13, 2018, 1:36 p.m. |
| Advent Challenge — Part 4 | 1,223 | April 12, 2018, 12:01 p.m. |
| Advent Challenge — Part 3 | 1,226 | April 9, 2018, 3:31 p.m. |
| Advent-Challenge — Part 2 | 1,222 | April 9, 2018, 12:22 p.m. |
| Advent-Challenge — Part 1 | 101 | April 3, 2018, 11:23 a.m. |
| Weakened Granit — Part 1 | 100 | April 12, 2016, 4:52 p.m. |
| Enigma Combinatorics | 100 | March 24, 2016, 7:34 a.m. |
| New Year's Greetings — Part 5 | 2,000 | March 21, 2016, 7:18 p.m. |
| New Year's Greetings — Part 4 | 200 | March 21, 2016, 2:14 p.m. |
| New Year's Greetings — Part 3 | 200 | March 21, 2016, 1:56 p.m. |
| New Year's Greetings — Part 2 | 200 | March 21, 2016, 1:20 p.m. |
| New Year's Greetings — Part 1 | 200 | March 21, 2016, 1:09 p.m. |
| Kaskade-S/T — Part 3 | 1,100 | March 8, 2016, 6:44 p.m. |
| Kaskade-S/T — Part 2 | 1,100 | March 3, 2016, 2:30 p.m. |
| Kaskade-S/T — Part 1 | 100 | March 2, 2016, 12:19 p.m. |
| Cascading Encryption — Part 3/3 | 1,116 | March 1, 2016, 3:51 p.m. |
| Cascading Encryption — Part 2/3 | 1,116 | March 1, 2016, 9:39 a.m. |
| M-138 — Part 3 | 1,153 | Feb. 2, 2016, 9:18 p.m. |
| M-138 — Part 2 | 1,153 | Jan. 30, 2016, 12:47 p.m. |
| Double Column Transposition — Part 4 | 1,135 | Jan. 29, 2016, 7:36 p.m. |
| The Book Code: A Challenge for Bookworms | 100 | Jan. 29, 2016, 12:30 p.m. |
| M-138 — Part 1 | 100 | Jan. 29, 2016, 10:11 a.m. |
| Turing Bombe Enigma I | 100 | Jan. 26, 2016, 4:31 p.m. |
| Double Column Transposition — Part 1 | 1,133 | Jan. 25, 2016, 12:19 p.m. |
| Enigma Part 2 | 1,099 | Jan. 22, 2016, 7:42 p.m. |
| Enigma Part 1 | 1,099 | Jan. 20, 2016, 8:19 p.m. |
| Enigma Messages | 100 | Jan. 20, 2016, 5:49 p.m. |
| Double Column Transposition — Part 3 | 1,135 | Jan. 16, 2016, 8:15 a.m. |
| Double Column Transposition — Part 2 | 1,135 | Jan. 16, 2016, 7:54 a.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | Jan. 11, 2016, 3:59 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | Jan. 11, 2016, 3:57 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | Jan. 11, 2016, 3:55 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | Jan. 11, 2016, 3:49 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | Jan. 11, 2016, 10:19 a.m. |
| Double Columnar Transposition | 100 | Jan. 5, 2016, 1:14 p.m. |
| News from Castle Mansfeld | 102 | Jan. 5, 2016, 11:25 a.m. |
| A Secret Message from Castle Mansfeld | 100 | Jan. 5, 2016, 10:10 a.m. |
| Monoalphabetic Substitution with Camouflage — Part 5 | 1,108 | Dec. 29, 2015, 7:29 p.m. |
| Concealed Messages — Vigenère's Night Sky | 1,109 | Dec. 29, 2015, 10 a.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | Dec. 24, 2015, 7:02 p.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,106 | Dec. 22, 2015, 7:08 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,106 | Dec. 22, 2015, 1:46 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Dec. 20, 2015, 4:31 p.m. |
| Ku Klux Klan | 1,000 | Dec. 13, 2015, 1:27 p.m. |
| Cascading Encryption — Part 1/3 | 100 | Dec. 1, 2015, 5:13 p.m. |
| Pigpen with a twist — Part 2 | 1,105 | Dec. 1, 2015, 10:36 a.m. |
| Pigpen with a twist — Part 3 | 1,105 | Nov. 29, 2015, 10:14 a.m. |
| ADFGVX — Part 1 | 100 | Nov. 29, 2015, 10:02 a.m. |
| ADFGVX — Part 2 | 100 | Nov. 28, 2015, 6:30 a.m. |
| Number Sequence — Part 5 | 100 | Nov. 27, 2015, 11:57 a.m. |
| Number Sequence — Part 7 | 100 | Nov. 25, 2015, 11:18 a.m. |
| Hill Cipher with Sudoku Key | 100 | Nov. 24, 2015, 9:21 a.m. |
| Molehunt (Part 3/3) | 1,100 | Nov. 24, 2015, 7:35 a.m. |
| Molehunt (Part 2/3) | 100 | Nov. 23, 2015, 8:31 a.m. |
| Molehunt (Part 1/3) | 100 | Nov. 23, 2015, 8:09 a.m. |
| BCR code (Book-Caesar-RSA) | 1,113 | Nov. 22, 2015, 8:30 a.m. |
| Multilingual Monoalphabetic Substitution | 100 | Nov. 21, 2015, 3:17 p.m. |
| Image Noise | 200 | Nov. 21, 2015, 1:19 p.m. |
| Unconcealed RSA messages | 1,106 | Nov. 20, 2015, 7:32 p.m. |
| Zodiac Cipher | 100 | Nov. 19, 2015, 9:01 a.m. |
| RSA: Two different keys — same ciphertext | 1,105 | Nov. 19, 2015, 7:13 a.m. |
| Hybrid Encryption I | 1,100 | Nov. 18, 2015, 4:03 p.m. |
| Classical Ciphers^3 | 100 | Nov. 18, 2015, 11:09 a.m. |
| Smartcard RSA | 1,100 | Nov. 17, 2015, 9:50 a.m. |
| Playfair with hints about the grid | 100 | Nov. 14, 2015, 5:11 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,108 | Nov. 12, 2015, 12:31 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | Nov. 11, 2015, 5:51 p.m. |
| Pigpen with a twist — Part 1 | 100 | Nov. 11, 2015, 11:42 a.m. |
| ¿No Hablas Español? No problemo! | 100 | Nov. 10, 2015, 1:47 p.m. |
| Playfair Encryption | 100 | Nov. 10, 2015, 1:19 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,100 | Nov. 10, 2015, 10:59 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Nov. 10, 2015, 10:06 a.m. |
| Alice's Birthday Party (Part 2) | 1,100 | Nov. 10, 2015, 7:29 a.m. |
| Alice's Birthday Party (Part 1) | 1,100 | Nov. 10, 2015, 7:19 a.m. |
| Broadcasting and low exponent — RSA Attack | 1,104 | Nov. 9, 2015, 2:26 p.m. |
| How do you become a big cryptographer? | 100 | Nov. 9, 2015, 10:39 a.m. |
| Factorization Cipher — Part 2 | 1,107 | Nov. 9, 2015, 8:37 a.m. |
| Snow White and the seven dwarfs | 100 | Nov. 7, 2015, 8:54 p.m. |
| An Invisible Message | 100 | Nov. 7, 2015, 6:29 p.m. |
| The Last Note | 100 | Nov. 7, 2015, 6:12 p.m. |
| Cracking SHA1-Hashed Passwords | 1,102 | Nov. 7, 2015, 2:55 p.m. |
| Modified Caesar Cipher | 100 | Nov. 6, 2015, 11:29 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Nov. 6, 2015, 8:15 a.m. |
| One-Time Pad with Flaws | 100 | Nov. 6, 2015, 7:45 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Nov. 6, 2015, 7:09 a.m. |
| Unusual encryption using a diophantine equation | 1,105 | Nov. 5, 2015, 2:57 p.m. |
| Factorization Cipher — Part 3 | 1,108 | Nov. 4, 2015, 6:01 p.m. |
| A hidden word — Part 2 | 100 | Nov. 3, 2015, 5:08 p.m. |
| An 'unhearable' message | 100 | Nov. 3, 2015, 10:04 a.m. |
| From Russia with Love | 100 | Nov. 3, 2015, 6:04 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Nov. 2, 2015, 5:50 p.m. |
| Nils away on travel | 100 | Nov. 2, 2015, 8:07 a.m. |
| Trifid Cipher | 100 | Nov. 1, 2015, 5:22 a.m. |
| Number Sequence — Part 8 | 102 | Oct. 31, 2015, 11:57 a.m. |
| Factorization Cipher — Part 1 | 100 | Oct. 30, 2015, 5:59 p.m. |
| Grille Cipher | 100 | Oct. 30, 2015, 6:39 a.m. |
| A hidden word | 100 | Oct. 29, 2015, 6:31 p.m. |
| Letter to the Templars — Part 3 | 1,115 | Oct. 29, 2015, 12:37 p.m. |
| Letter to the Templars — Part 2 | 100 | Oct. 29, 2015, 12:10 p.m. |
| Monoalphabetic Substitution | 100 | Oct. 29, 2015, 11:49 a.m. |
| Number Sequence — Part 3 | 100 | Oct. 29, 2015, 6:25 a.m. |
| Number Sequence — Part 4 | 100 | Oct. 28, 2015, 1:43 p.m. |
| Letter to the Templars — Part 1 | 100 | Oct. 28, 2015, 12:30 p.m. |
| Number Sequence — Part 2 | 100 | Oct. 28, 2015, 11:39 a.m. |
| Beaver Code | 100 | Oct. 28, 2015, 11:20 a.m. |
| Caesar Encryption | 100 | Oct. 28, 2015, 10:54 a.m. |
| Original Caesar Cipher | 100 | Oct. 28, 2015, 10:29 a.m. |
| Number Sequence | 100 | Oct. 28, 2015, 10:20 a.m. |
Gold5
Silver0
Bronze0
