| Hill Cipher with Sudoku Key | 100 | Jan. 5, 2023, 12:54 p.m. |
| Kaskade-S/T — Part 1 | 100 | Jan. 2, 2023, 9:14 a.m. |
| Merkle-Hellman Knapsack Challenge - Part 1 | 101 | Dec. 31, 2022, 5:05 p.m. |
| ORYX Stream Cipher Part II | 1,078 | Dec. 22, 2022, 6:26 p.m. |
| ORYX Stream Cipher Part I | 1,079 | Dec. 21, 2022, 5:24 p.m. |
| Advent Challenge — Part 4 | 1,100 | Dec. 19, 2022, 3:54 p.m. |
| RSA Factoring Challenge: RSA-232 | 0 | Dec. 18, 2022, 4:58 p.m. |
| Summer Job | 1,103 | Dec. 18, 2022, 4:56 p.m. |
| RSA Factoring Challenge: RSA-220 | 0 | Dec. 18, 2022, 4:31 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | Dec. 18, 2022, 12:36 p.m. |
| The Last Note | 100 | Dec. 17, 2022, 8:10 p.m. |
| Strange Message from Thessaloniki | 100 | Dec. 17, 2022, 6:21 p.m. |
| Modular Sequences | 100 | Dec. 17, 2022, 4:13 p.m. |
| News from Castle Mansfeld | 100 | Dec. 17, 2022, 1:26 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | Dec. 16, 2022, 7:01 p.m. |
| ¿No Hablas Español? No problemo! | 100 | Dec. 16, 2022, 11:05 a.m. |
| Number Sequence — Part 7 | 100 | Dec. 15, 2022, 7:37 p.m. |
| Number Sequence — Part 6 | 100 | Dec. 15, 2022, 7:34 p.m. |
| Number Sequence — Part 9 | 100 | Dec. 15, 2022, 7:31 p.m. |
| Number Sequence — Part 10 | 100 | Dec. 15, 2022, 7:26 p.m. |
| Autokey Cipher | 100 | Dec. 15, 2022, 6:55 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Dec. 15, 2022, 6:13 p.m. |
| Find the right route — Part 1 | 100 | Dec. 15, 2022, 4:48 p.m. |
| Wheatstone Cryptograph — Part 1 | 100 | Dec. 12, 2022, 7:18 p.m. |
| Alberti Challenge — Part 1 | 100 | Dec. 12, 2022, 4:55 p.m. |
| The Syllabary Cipher – Part 1 | 102 | Dec. 12, 2022, 4:33 p.m. |
| Factorization Cipher — Part 3 | 1,090 | April 17, 2019, 4:12 p.m. |
| M-138 — Part 2 | 1,104 | April 16, 2019, 6:34 p.m. |
| M-138 — Part 1 | 100 | April 16, 2019, 8:39 a.m. |
| Advent-Challenge — Part 1 | 100 | April 16, 2019, 7:50 a.m. |
| Number Sequence — Part 8 | 100 | April 16, 2019, 7:35 a.m. |
| Factorization Cipher — Part 2 | 1,126 | Feb. 9, 2014, 10:49 a.m. |
| Unusual encryption using a diophantine equation | 1,122 | Feb. 9, 2014, 8:30 a.m. |
| From Russia with Love | 101 | Feb. 8, 2014, 5:55 p.m. |
| RSA Factoring Challenge: RSA-704 | 0 | Aug. 1, 2013, 10:15 a.m. |
| BCR code (Book-Caesar-RSA) | 1,163 | July 31, 2013, 12:34 p.m. |
| Hybrid Encryption I | 1,118 | July 30, 2013, 12:16 p.m. |
| RSA: Two different keys — same ciphertext | 1,130 | July 29, 2013, 10:23 a.m. |
| How do you become a big cryptographer? | 100 | July 27, 2013, 11:36 a.m. |
| Reserve Hand Procedure — Part 1 | 101 | July 27, 2013, 9:30 a.m. |
| Snow White and the seven dwarfs | 101 | July 26, 2013, 10:25 a.m. |
| Grille Cipher | 100 | July 15, 2013, 10:26 a.m. |
| A hidden word | 101 | July 10, 2013, 11:54 a.m. |
| Pigpen with a twist — Part 1 | 100 | Oct. 20, 2012, 7:46 a.m. |
| Beaver Code | 102 | Oct. 18, 2012, 12:34 p.m. |
| Letter to the Templars — Part 3 | 1,502 | Oct. 18, 2012, 12:02 p.m. |
| Letter to the Templars — Part 2 | 101 | Oct. 18, 2012, 11:42 a.m. |
| Letter to the Templars — Part 1 | 101 | Oct. 18, 2012, 11:22 a.m. |
| Broadcasting and low exponent — RSA Attack | 1,160 | July 1, 2012, 11:02 a.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,135 | June 24, 2012, 5:14 p.m. |
| Cracking SHA1-Hashed Passwords | 1,149 | June 23, 2012, 6:39 p.m. |
| Modified Caesar Cipher | 100 | June 23, 2012, 1:07 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | June 23, 2012, 11:20 a.m. |
| One-Time Pad with Flaws | 100 | June 23, 2012, 11:04 a.m. |
| Number Sequence — Part 4 | 102 | June 23, 2012, 10 a.m. |
| Number Sequence — Part 3 | 101 | June 23, 2012, 9:57 a.m. |
| Factorization Cipher — Part 1 | 101 | Feb. 17, 2012, 4:43 p.m. |
| A really long number sequence | 1,199 | Feb. 17, 2012, 4:20 p.m. |
| Number Sequence — Part 2 | 100 | Feb. 16, 2012, 6:07 p.m. |
| Original Caesar Cipher | 106 | Jan. 1, 2011, 11:35 a.m. |
| Zodiac Cipher | 109 | Oct. 24, 2010, 8:16 p.m. |
| Enigma Part 2 | 1,485 | Oct. 23, 2010, 5:30 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 200 | Oct. 22, 2010, 10:55 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 200 | Oct. 22, 2010, 10:45 a.m. |
| Enigma Part 1 | 1,523 | Oct. 22, 2010, 9:32 a.m. |
| Caesar Encryption | 200 | Oct. 22, 2010, 8:58 a.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,547 | Oct. 20, 2010, 7:07 p.m. |
| Alice's Birthday Party (Part 2) | 1,613 | Oct. 19, 2010, 9:52 a.m. |
| Alice's Birthday Party (Part 1) | 1,613 | Oct. 18, 2010, 8:06 p.m. |
| A Secret Message from Castle Mansfeld | 120 | Oct. 18, 2010, 6:16 p.m. |
| Classical Ciphers^3 | 120 | Oct. 18, 2010, 4:54 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 125 | Oct. 17, 2010, 8:44 p.m. |
| Monoalphabetic Substitution | 125 | Oct. 17, 2010, 5:50 p.m. |
| Number Sequence | 133 | Oct. 17, 2010, 12:04 p.m. |
Gold1
Silver0
Bronze3
