| The Syllabary Cipher – Part 1 | 200 | Oct. 28, 2022, 8:45 p.m. |
| Merkle-Hellman Knapsack Challenge - Part 1 | 111 | Oct. 22, 2022, 7:24 p.m. |
| Alberti Challenge — Part 1 | 150 | March 27, 2022, 11:41 p.m. |
| Wheatstone Cryptograph — Part 1 | 150 | April 22, 2021, 10:54 p.m. |
| RSA: Two different keys — same ciphertext | 1,085 | Aug. 3, 2020, 12:41 a.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Aug. 2, 2020, 10:04 a.m. |
| Lightweight Introduction to Lattices — Part 2 | 104 | July 20, 2020, 9:59 p.m. |
| Lightweight Introduction to Lattices — Part 3 | 1,613 | July 20, 2020, 8:20 p.m. |
| Pigpen with a twist — Part 1 | 100 | June 14, 2020, 5:27 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,084 | June 7, 2020, 7:36 p.m. |
| Modular Sequences | 100 | May 29, 2020, 1:37 a.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | May 27, 2020, 12:18 a.m. |
| Monoalphabetic Substitution | 100 | May 25, 2020, 5:43 p.m. |
| Lightweight Introduction to Lattices — Part 1 | 150 | May 18, 2020, 12:57 a.m. |
| Summer Job | 1,185 | Jan. 8, 2019, 9:53 p.m. |
| Enigma Part 2 | 1,087 | Jan. 8, 2019, 1:07 a.m. |
| Cascading Encryption — Part 1/3 | 100 | Jan. 7, 2019, 11:23 p.m. |
| Molehunt (Part 2/3) | 100 | Jan. 7, 2019, 8:50 p.m. |
| Molehunt (Part 1/3) | 100 | Jan. 7, 2019, 8:29 p.m. |
| Kaskade-S/T — Part 1 | 100 | Dec. 15, 2018, 12:20 p.m. |
| Number Sequence — Part 7 | 100 | Dec. 11, 2018, 11:17 p.m. |
| Enigma Messages | 100 | Dec. 11, 2018, 8:49 a.m. |
| Autokey Cipher | 106 | Oct. 11, 2018, 12:10 a.m. |
| Number Sequence — Part 10 | 200 | April 18, 2018, 10:28 p.m. |
| Advent Challenge — Part 4 | 1,229 | April 2, 2018, 11:48 a.m. |
| Double Columnar Transposition | 100 | March 18, 2018, 7:35 p.m. |
| Alice's Birthday Party (Part 2) | 1,090 | March 16, 2018, 4:53 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,093 | March 16, 2018, 12:29 a.m. |
| Alice's Birthday Party (Part 1) | 1,090 | March 15, 2018, 1:21 a.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,090 | March 15, 2018, 12:44 a.m. |
| The Einstein Enigma | 1,324 | March 13, 2018, 7:04 p.m. |
| ADFGVX — Part 1 | 100 | March 11, 2018, 11:48 p.m. |
| Image Noise | 100 | Feb. 5, 2018, 10:19 p.m. |
| ADFGVX — Part 2 | 100 | Feb. 5, 2018, 9:28 p.m. |
| New Year's Greetings — Part 4 | 100 | Feb. 4, 2018, 11:08 p.m. |
| New Year's Greetings — Part 3 | 100 | Feb. 4, 2018, 10:01 p.m. |
| New Year's Greetings — Part 2 | 100 | Feb. 4, 2018, 9:23 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Feb. 2, 2018, 12:40 a.m. |
| Playfair Encryption | 100 | Jan. 25, 2018, 7:53 p.m. |
| Playfair with hints about the grid | 100 | Jan. 25, 2018, 7:32 p.m. |
| New Year's Greetings — Part 1 | 100 | Jan. 20, 2018, 9:17 p.m. |
| Number Sequence — Part 9 | 102 | Jan. 14, 2018, 4:40 p.m. |
| Advent-Challenge — Part 1 | 103 | Jan. 13, 2018, 1:07 p.m. |
| Classical Ciphers^3 | 100 | Dec. 31, 2016, 4:38 p.m. |
| Enigma Combinatorics | 100 | Dec. 29, 2016, 11:57 p.m. |
| How do you become a big cryptographer? | 100 | Dec. 29, 2016, 11:04 p.m. |
| ¿No Hablas Español? No problemo! | 100 | Dec. 29, 2016, 9 p.m. |
| Trifid Cipher | 100 | Dec. 29, 2016, 6:09 p.m. |
| Factorization Cipher — Part 3 | 1,100 | Dec. 27, 2016, 4:17 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Dec. 25, 2016, 3:27 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Dec. 24, 2016, 1:18 a.m. |
| Snow White and the seven dwarfs | 100 | Dec. 23, 2016, 8:44 p.m. |
| Hill Cipher with Sudoku Key | 100 | Dec. 23, 2016, 7:57 p.m. |
| Number Sequence — Part 5 | 100 | Feb. 16, 2016, 6:39 p.m. |
| Number Sequence — Part 6 | 100 | Feb. 11, 2016, 4 p.m. |
| Number Sequence — Part 3 | 100 | Feb. 11, 2016, 3:35 p.m. |
| Nils away on travel | 100 | Feb. 4, 2016, 6:12 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | Feb. 3, 2016, 4:53 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | Feb. 3, 2016, 1:36 a.m. |
| Modified Caesar Cipher | 100 | Feb. 1, 2016, 11:57 p.m. |
| Factorization Cipher — Part 2 | 1,105 | Feb. 1, 2016, 1:42 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | Jan. 23, 2016, 11:10 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | Jan. 23, 2016, 8:17 p.m. |
| M-138 — Part 2 | 1,154 | Jan. 23, 2016, 6:52 p.m. |
| From Russia with Love | 100 | Jan. 23, 2016, 1:39 a.m. |
| M-138 — Part 1 | 100 | Jan. 22, 2016, 11:33 p.m. |
| Enigma Part 1 | 1,099 | Jan. 22, 2016, 5:15 p.m. |
| A hidden word — Part 2 | 100 | Jan. 19, 2016, 11:04 p.m. |
| Number Sequence — Part 8 | 101 | Jan. 19, 2016, 10:30 p.m. |
| One-Time Pad with Flaws | 100 | Feb. 12, 2014, 6:57 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 101 | Feb. 12, 2014, 12:19 a.m. |
| Reserve Hand Procedure — Part 1 | 100 | Feb. 11, 2014, 8:11 p.m. |
| Number Sequence — Part 4 | 100 | Feb. 11, 2014, 5:44 p.m. |
| Cracking SHA1-Hashed Passwords | 1,117 | Feb. 10, 2014, 11:45 p.m. |
| Letter to the Templars — Part 3 | 1,145 | Feb. 9, 2014, 9:55 p.m. |
| Grille Cipher | 100 | Feb. 9, 2014, 9:32 p.m. |
| A hidden word | 100 | Feb. 9, 2014, 8:54 p.m. |
| Factorization Cipher — Part 1 | 100 | Feb. 9, 2014, 8:44 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Feb. 9, 2014, 8:05 p.m. |
| Letter to the Templars — Part 2 | 100 | Feb. 9, 2014, 7:51 p.m. |
| Letter to the Templars — Part 1 | 100 | Feb. 9, 2014, 7:21 p.m. |
| Caesar Encryption | 100 | Feb. 9, 2014, 6:26 p.m. |
| Beaver Code | 100 | Feb. 9, 2014, 6:13 p.m. |
| Number Sequence — Part 2 | 100 | Feb. 9, 2014, 5:31 p.m. |
| Original Caesar Cipher | 100 | Feb. 9, 2014, 5:28 p.m. |
| Number Sequence | 100 | Feb. 9, 2014, 5:19 p.m. |
Gold0
Silver0
Bronze0
