| The Syllabary Cipher – Part 2 | 1,576 | Nov. 2, 2022, 7:07 p.m. |
| The Syllabary Cipher – Part 3 | 1,824 | Oct. 29, 2022, 1:37 p.m. |
| Lightweight Introduction to Lattices — Part 3 | 1,124 | Oct. 28, 2022, 5:14 p.m. |
| Hill Cipher with Sudoku Key | 100 | Oct. 28, 2022, 4:43 p.m. |
| The Syllabary Cipher – Part 1 | 200 | Oct. 28, 2022, 4:41 p.m. |
| Lightweight Introduction to Lattices — Part 2 | 100 | Oct. 22, 2022, 10:48 a.m. |
| Lightweight Introduction to Lattices — Part 1 | 100 | Oct. 22, 2022, 10:47 a.m. |
| Find the right route — Part 3 | 100 | Oct. 22, 2022, 10:45 a.m. |
| Find the right route — Part 2 | 100 | Oct. 22, 2022, 10:33 a.m. |
| Find the right route — Part 1 | 100 | Oct. 22, 2022, 10:33 a.m. |
| Wheatstone Cryptograph — Part 1 | 100 | Oct. 22, 2022, 10:32 a.m. |
| Merkle-Hellman Knapsack Challenge - Part 1 | 120 | Oct. 19, 2022, 4:11 p.m. |
| Number Sequence — Part 6 | 100 | Oct. 19, 2022, 4:10 p.m. |
| Alberti Challenge — Part 1 | 100 | Oct. 19, 2022, 4:07 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Nov. 17, 2019, 2:47 p.m. |
| News from Castle Mansfeld | 100 | Nov. 15, 2018, 7:37 a.m. |
| Modular Sequences | 102 | Nov. 15, 2018, 7:33 a.m. |
| Advent Challenge — Part 3 | 1,163 | Nov. 8, 2018, 6:58 p.m. |
| Advent-Challenge — Part 2 | 1,162 | Nov. 8, 2018, 6:57 p.m. |
| Summer Job | 1,204 | Nov. 8, 2018, 6:53 p.m. |
| Autokey Cipher | 102 | Nov. 8, 2018, 6:43 p.m. |
| Advent-Challenge — Part 1 | 100 | Nov. 8, 2018, 6:41 p.m. |
| Number Sequence — Part 10 | 100 | Nov. 8, 2018, 6:38 p.m. |
| Cryptanalysis Hacking Puzzles — Part 1 | 108 | Nov. 8, 2018, 6:35 p.m. |
| Weakened Granit — Part 1 | 100 | Sept. 17, 2016, 12:24 p.m. |
| The Last Note | 100 | Sept. 17, 2016, 12:19 p.m. |
| Number Sequence — Part 8 | 100 | Sept. 17, 2016, 12:18 p.m. |
| Image Noise | 100 | Sept. 17, 2016, 12:17 p.m. |
| New Year's Greetings — Part 5 | 1,193 | Sept. 17, 2016, 12:16 p.m. |
| New Year's Greetings — Part 4 | 101 | Sept. 17, 2016, 12:15 p.m. |
| New Year's Greetings — Part 3 | 101 | Sept. 17, 2016, 12:15 p.m. |
| New Year's Greetings — Part 2 | 101 | Sept. 17, 2016, 12:14 p.m. |
| New Year's Greetings — Part 1 | 101 | Sept. 17, 2016, 12:13 p.m. |
| M-138 — Part 2 | 1,214 | May 1, 2015, 10:30 a.m. |
| M-138 — Part 1 | 101 | May 1, 2015, 10:29 a.m. |
| A hidden word — Part 2 | 107 | May 1, 2015, 10:28 a.m. |
| Trifid Cipher | 200 | Oct. 29, 2013, 1:43 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 117 | Oct. 2, 2013, 11:01 a.m. |
| From Russia with Love | 200 | Sept. 5, 2013, 11:58 a.m. |
| Nils away on travel | 200 | Aug. 9, 2013, 11:02 a.m. |
| ORYX Stream Cipher — Part 3 (revised) | 1,547 | June 13, 2013, 12:21 p.m. |
| Snow White and the seven dwarfs | 120 | April 24, 2013, 9:25 p.m. |
| Reserve Hand Procedure — Part 1 | 200 | March 7, 2013, 1:40 p.m. |
| Turing Bombe Enigma I | 100 | Jan. 28, 2013, 8:12 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | Jan. 28, 2013, 1:39 a.m. |
| Cascading Encryption — Part 1/3 | 200 | Jan. 26, 2013, 3:09 a.m. |
| Enigma Messages | 200 | Jan. 24, 2013, 10:43 a.m. |
| ORYX Stream Cipher Part II | 1,125 | Jan. 20, 2013, 2:16 a.m. |
| ORYX Stream Cipher Part I | 1,125 | Jan. 16, 2013, 11:15 p.m. |
| Playfair with hints about the grid | 200 | Jan. 16, 2013, 5:40 p.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,129 | Jan. 11, 2013, 11:50 p.m. |
| Ku Klux Klan | 1,000 | Jan. 11, 2013, 12:45 p.m. |
| A hidden word | 150 | Jan. 8, 2013, 8:44 a.m. |
| Strange Message from Thessaloniki | 200 | Dec. 10, 2012, 8:46 p.m. |
| Recycled One-Time Pad | 114 | Nov. 26, 2012, 5:48 p.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | Nov. 9, 2012, 6:25 p.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,161 | Nov. 9, 2012, 5:22 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,161 | Nov. 9, 2012, 5:22 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Nov. 9, 2012, 5:21 p.m. |
| Pigpen with a twist — Part 3 | 1,150 | Nov. 8, 2012, 5:15 p.m. |
| Pigpen with a twist — Part 2 | 1,150 | Nov. 8, 2012, 5:15 p.m. |
| Letter to the Templars — Part 3 | 2,000 | Oct. 10, 2012, 10:03 a.m. |
| BCR code (Book-Caesar-RSA) | 1,824 | Sept. 14, 2012, 4:54 p.m. |
| Beaver Code | 200 | Aug. 14, 2012, 11:41 a.m. |
| Letter to the Templars — Part 2 | 200 | July 31, 2012, 11:35 a.m. |
| Letter to the Templars — Part 1 | 200 | July 17, 2012, 11:03 a.m. |
| Kaskade-S/T — Part 2 | 1,147 | June 7, 2012, 7:25 p.m. |
| Kaskade-S/T — Part 1 | 100 | June 3, 2012, 8:57 p.m. |
| How do you become a big cryptographer? | 200 | May 28, 2012, 8:05 p.m. |
| Keyshanc — Part 2 | 1,824 | May 22, 2012, 10:20 p.m. |
| Keyshanc — Part 1 | 1,824 | May 22, 2012, 9:14 p.m. |
| ¿No Hablas Español? No problemo! | 114 | April 25, 2012, 2:45 p.m. |
| Number Sequence — Part 4 | 114 | April 25, 2012, 6:50 a.m. |
| Hybrid Encryption I | 1,142 | April 12, 2012, 11:22 a.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,241 | April 12, 2012, 11:20 a.m. |
| Pigpen with a twist — Part 1 | 100 | April 5, 2012, 10:04 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,278 | April 5, 2012, 10:03 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,141 | April 3, 2012, 9:45 a.m. |
| Molehunt (Part 3/3) | 1,142 | April 2, 2012, 10:21 a.m. |
| Molehunt (Part 2/3) | 100 | April 2, 2012, 10:21 a.m. |
| Molehunt (Part 1/3) | 100 | April 2, 2012, 10:20 a.m. |
| Number Sequence — Part 3 | 200 | March 31, 2012, 10:54 a.m. |
| An Invisible Message | 101 | March 24, 2012, 12:20 p.m. |
| Music Code — Part 2 | 1,165 | March 22, 2012, 9:36 a.m. |
| Music Code — Part 1 | 100 | March 22, 2012, 9:35 a.m. |
| A Secret Message from Castle Mansfeld | 100 | March 22, 2012, 9:35 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | March 22, 2012, 9:34 a.m. |
| Factorization Cipher — Part 2 | 1,223 | March 22, 2012, 9:25 a.m. |
| The Book Code: A Challenge for Bookworms | 200 | March 21, 2012, 4:45 p.m. |
| Factorization Cipher — Part 3 | 1,259 | March 15, 2012, 9:28 a.m. |
| Enigma Combinatorics | 100 | March 15, 2012, 9:28 a.m. |
| Enigma Part 1 | 1,142 | March 14, 2012, 10:58 a.m. |
| A really long number sequence | 1,191 | March 12, 2012, 1:15 p.m. |
| Modified Caesar Cipher | 101 | March 9, 2012, 12:38 p.m. |
| Classical Ciphers^3 | 100 | March 8, 2012, 10:32 p.m. |
| ADFGVX — Part 2 | 100 | March 8, 2012, 7:48 p.m. |
| ADFGVX — Part 1 | 100 | March 8, 2012, 7:48 p.m. |
| ECDH-Key Exchange for Beginners | 200 | Feb. 24, 2012, 10:54 a.m. |
| Grille Cipher | 101 | Feb. 22, 2012, 1:33 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,184 | Feb. 21, 2012, 9:41 p.m. |
| RSA: Two different keys — same ciphertext | 1,190 | Feb. 21, 2012, 9:22 p.m. |
| Cracking SHA1-Hashed Passwords | 1,163 | Feb. 19, 2012, 9:05 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Feb. 19, 2012, 7:29 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Feb. 19, 2012, 7 p.m. |
| Alice's Birthday Party (Part 2) | 1,144 | Feb. 19, 2012, 1:21 a.m. |
| Alice's Birthday Party (Part 1) | 1,144 | Feb. 19, 2012, 12:22 a.m. |
| Double Columnar Transposition | 101 | Feb. 17, 2012, 1:37 p.m. |
| Caesar Encryption | 100 | Feb. 16, 2012, 11:49 p.m. |
| Factorization Cipher — Part 1 | 101 | Feb. 16, 2012, 11:45 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,145 | Feb. 16, 2012, midnight |
| Number Sequence — Part 2 | 100 | Feb. 14, 2012, 7:02 p.m. |
| Number Sequence | 100 | Feb. 14, 2012, 6:57 p.m. |
| Monoalphabetic Substitution | 100 | Feb. 14, 2012, 6:45 p.m. |
| One-Time Pad with Flaws | 100 | Feb. 14, 2012, 5:46 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 101 | Feb. 14, 2012, 5:41 p.m. |
| Original Caesar Cipher | 100 | Feb. 14, 2012, 5:39 p.m. |
Gold4
Silver2
Bronze0
