| Merkle-Hellman Knapsack Challenge - Part 1 | 101 | April 19, 2023, 9:32 p.m. |
| The Syllabary Cipher – Part 1 | 103 | Nov. 27, 2022, 11:23 a.m. |
| Lightweight Introduction to Lattices — Part 1 | 100 | July 9, 2022, 9:47 p.m. |
| Alberti Challenge — Part 1 | 102 | May 15, 2022, 9:17 a.m. |
| Wheatstone Cryptograph — Part 1 | 100 | May 15, 2022, 8:37 a.m. |
| Find the right route — Part 1 | 101 | Feb. 7, 2021, 3:03 p.m. |
| Recycled One-Time Pad | 100 | April 26, 2020, 6:29 p.m. |
| Modular Sequences | 100 | March 17, 2020, 3:52 p.m. |
| Smartcard RSA | 1,084 | Feb. 23, 2020, 7:50 p.m. |
| Turing Bombe Enigma I | 100 | Feb. 16, 2020, 6:09 p.m. |
| Fastest in the West | 1,139 | Jan. 1, 2020, 12:07 p.m. |
| Zodiac Cipher | 100 | Dec. 31, 2019, 8:07 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Dec. 20, 2019, 3:51 p.m. |
| Monoalphabetic Substitution with Nostradamus Flavor | 1,660 | Feb. 19, 2019, 6:42 p.m. |
| Autokey Cipher | 101 | Dec. 2, 2018, 8:45 a.m. |
| The Einstein Enigma | 1,167 | Nov. 30, 2018, 10:19 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,093 | Aug. 8, 2018, 10:25 p.m. |
| Trendy Messenger | 1,278 | Aug. 6, 2018, 5:43 a.m. |
| Number Sequence — Part 5 | 100 | Aug. 5, 2018, 7 p.m. |
| Number Sequence — Part 10 | 101 | Aug. 5, 2018, 6:03 p.m. |
| Summer Job | 1,279 | Aug. 4, 2018, 9:30 p.m. |
| Advent-Challenge — Part 1 | 101 | March 17, 2018, 5:57 a.m. |
| Number Sequence — Part 9 | 101 | March 16, 2018, 7:20 p.m. |
| Number Sequence — Part 6 | 100 | March 16, 2018, 7:01 p.m. |
| ORYX Stream Cipher — Part 3 (revised) | 1,118 | March 20, 2016, 7:29 p.m. |
| ORYX Stream Cipher Part II | 1,098 | March 19, 2016, 6:49 p.m. |
| ORYX Stream Cipher Part I | 1,098 | March 19, 2016, 3:49 p.m. |
| Double Columnar Transposition | 100 | March 9, 2016, 7:06 p.m. |
| Weakened Handycipher — Part 1 | 1,167 | March 7, 2016, 5:20 a.m. |
| News from Castle Mansfeld | 101 | Feb. 21, 2016, 3:46 p.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,101 | Dec. 7, 2015, 2:43 a.m. |
| Weakened Granit — Part 1 | 101 | Dec. 6, 2015, 1:53 p.m. |
| Typex — Part 1 | 1,118 | Dec. 5, 2015, 1:59 p.m. |
| Image Noise | 113 | Nov. 28, 2015, 11:50 a.m. |
| Number Sequence — Part 8 | 103 | Oct. 14, 2015, 11:02 p.m. |
| Number Sequence — Part 7 | 102 | May 10, 2015, 6:12 p.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,113 | April 22, 2015, 11:09 p.m. |
| CMEA 1 | 1,104 | April 21, 2015, 5:46 p.m. |
| Factorization Cipher — Part 3 | 1,112 | April 18, 2015, 11:51 p.m. |
| An 'unhearable' message | 100 | April 18, 2015, 1:23 p.m. |
| A hidden word — Part 2 | 150 | April 17, 2015, 9:04 p.m. |
| Playfair Encryption | 100 | April 17, 2015, 8:24 p.m. |
| ¿No Hablas Español? No problemo! | 100 | April 17, 2015, 7:58 p.m. |
| A really long number sequence | 1,109 | April 14, 2015, 10:55 p.m. |
| BCR code (Book-Caesar-RSA) | 1,120 | April 12, 2015, 1:30 p.m. |
| Enigma Part 2 | 1,103 | April 11, 2015, 2:03 p.m. |
| Enigma Part 1 | 1,103 | April 11, 2015, 11:57 a.m. |
| Heartbleed — Part 2 | 100 | March 22, 2015, 1:35 a.m. |
| Heartbleed — Part 1 | 100 | March 21, 2015, 11:58 a.m. |
| M-138 — Part 2 | 1,245 | March 15, 2015, 11:56 a.m. |
| The Last Note | 101 | March 15, 2015, 2:28 a.m. |
| M-138 — Part 1 | 101 | March 14, 2015, 2:35 p.m. |
| An Invisible Message | 100 | Aug. 9, 2014, 9:33 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Aug. 8, 2014, 5:38 p.m. |
| Playfair with hints about the grid | 100 | May 4, 2014, 9:26 a.m. |
| Multilingual Monoalphabetic Substitution | 100 | May 3, 2014, 9:19 p.m. |
| ADFGVX — Part 1 | 100 | May 3, 2014, 12:37 p.m. |
| ADFGVX — Part 2 | 100 | May 3, 2014, 11:37 a.m. |
| Strange Message from Thessaloniki | 100 | May 3, 2014, 12:18 a.m. |
| Enigma Messages with Repeated Letters — Part 5 | 102 | May 2, 2014, 5:24 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 102 | May 2, 2014, 5:17 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 102 | May 2, 2014, 5:07 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 101 | May 2, 2014, 4:49 p.m. |
| Hill Cipher with Sudoku Key | 100 | May 1, 2014, 6:20 p.m. |
| Molehunt (Part 3/3) | 1,110 | May 1, 2014, 2:16 p.m. |
| Molehunt (Part 2/3) | 100 | May 1, 2014, 10:28 a.m. |
| Molehunt (Part 1/3) | 100 | May 1, 2014, 10:08 a.m. |
| Cascading Encryption — Part 1/3 | 100 | April 30, 2014, 11:15 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,110 | April 28, 2014, 12:30 a.m. |
| A Secret Message from Castle Mansfeld | 100 | April 27, 2014, 11:51 a.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | April 25, 2014, 9:14 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | April 21, 2014, 11:03 a.m. |
| Enigma Messages | 100 | April 21, 2014, 10:52 a.m. |
| Kaskade-S/T — Part 1 | 100 | April 20, 2014, 3:51 p.m. |
| Pigpen with a twist — Part 1 | 100 | April 20, 2014, 11:38 a.m. |
| Nils away on travel | 100 | April 19, 2014, 3:41 p.m. |
| Factorization Cipher — Part 2 | 1,123 | April 18, 2014, 1:16 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,111 | April 6, 2014, 10:46 p.m. |
| How do you become a big cryptographer? | 100 | April 6, 2014, 3:27 p.m. |
| RSA: Two different keys — same ciphertext | 1,119 | April 6, 2014, 12:39 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | April 6, 2014, 11:24 a.m. |
| Enigma Combinatorics | 100 | April 6, 2014, 10:42 a.m. |
| Modified Caesar Cipher | 100 | April 5, 2014, 11:03 p.m. |
| Hybrid Encryption I | 1,111 | April 5, 2014, 9:18 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | April 5, 2014, 5:43 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,119 | April 5, 2014, 2:09 p.m. |
| Letter to the Templars — Part 3 | 1,140 | April 5, 2014, 1:51 p.m. |
| One-Time Pad with Flaws | 100 | April 4, 2014, 11:02 p.m. |
| Trifid Cipher | 101 | April 4, 2014, 9:03 p.m. |
| ECDH-Key Exchange for Beginners | 100 | April 1, 2014, 9:40 p.m. |
| Alice's Birthday Party (Part 2) | 1,111 | March 30, 2014, 5:34 p.m. |
| Alice's Birthday Party (Part 1) | 1,111 | March 30, 2014, 3:54 p.m. |
| Snow White and the seven dwarfs | 100 | March 29, 2014, 6:01 p.m. |
| Cracking SHA1-Hashed Passwords | 1,115 | March 29, 2014, 4:45 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | March 29, 2014, 1:12 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | March 29, 2014, 12:13 p.m. |
| Classical Ciphers^3 | 100 | March 29, 2014, 11:44 a.m. |
| The Book Code: A Challenge for Bookworms | 100 | March 27, 2014, 9:55 p.m. |
| Factorization Cipher — Part 1 | 100 | March 26, 2014, 4:12 a.m. |
| Number Sequence — Part 3 | 100 | March 25, 2014, 6:35 p.m. |
| Number Sequence — Part 4 | 100 | March 24, 2014, 7:36 p.m. |
| Letter to the Templars — Part 2 | 100 | March 23, 2014, 10:28 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | March 23, 2014, 7:24 p.m. |
| Monoalphabetic Substitution | 100 | March 23, 2014, 6:50 p.m. |
| From Russia with Love | 100 | March 23, 2014, 5:06 p.m. |
| Grille Cipher | 100 | March 23, 2014, 4:20 p.m. |
| A hidden word | 100 | March 23, 2014, 3:50 p.m. |
| Letter to the Templars — Part 1 | 100 | March 23, 2014, 3:18 p.m. |
| Beaver Code | 100 | March 23, 2014, 2:10 p.m. |
| Caesar Encryption | 100 | March 23, 2014, 1:50 p.m. |
| Number Sequence — Part 2 | 100 | March 23, 2014, 1:17 p.m. |
| Original Caesar Cipher | 100 | March 23, 2014, 1:12 p.m. |
| Number Sequence | 100 | March 23, 2014, 1:09 p.m. |
Gold0
Silver0
Bronze0
