| The Hutton Cipher – Part 2 | 1,824 | June 6, 2023, 7 p.m. |
| The Hutton Cipher – Part 1 | 1,414 | May 17, 2023, 11:08 p.m. |
| The Syllabary Cipher – Part 1 | 200 | Oct. 28, 2022, 10:48 p.m. |
| Merkle-Hellman Knapsack Challenge — Part 2 | 1,660 | Oct. 18, 2022, 4:37 p.m. |
| Merkle-Hellman Knapsack Challenge - Part 1 | 200 | Oct. 14, 2022, 8:11 p.m. |
| The SZ42 Challenge — Part 10 | 1,135 | Oct. 13, 2022, 9:08 p.m. |
| The SZ42 Challenge — Part 9 | 1,133 | Oct. 1, 2022, 12:20 a.m. |
| The SZ42 Challenge — Part 8 | 1,131 | Oct. 1, 2022, 12:20 a.m. |
| The SZ42 Challenge — Part 7 | 1,130 | Oct. 1, 2022, 12:18 a.m. |
| The SZ42 Challenge — Part 6 | 1,129 | Sept. 28, 2022, 11:39 p.m. |
| The SZ42 Challenge — Part 5 | 1,128 | Sept. 26, 2022, 11:33 p.m. |
| The SZ42 Challenge — Part 4 | 1,128 | Sept. 26, 2022, 11:24 p.m. |
| The SZ42 Challenge — Part 3 | 1,127 | Sept. 26, 2022, 11:02 p.m. |
| The SZ42 Challenge — Part 2 | 1,127 | Sept. 25, 2022, 1:57 a.m. |
| The SZ42 Challenge — Part 1 | 1,126 | Sept. 25, 2022, 12:12 a.m. |
| Playfair with hints about the grid | 100 | Sept. 22, 2022, 12:09 p.m. |
| Ku Klux Klan | 1,000 | Sept. 12, 2022, 2:17 p.m. |
| Hill Cipher | 1,523 | Sept. 11, 2022, 11:50 p.m. |
| Modified Vigenère Cipher | 1,183 | Aug. 27, 2022, 2:14 p.m. |
| Alberti Challenge — Part 2 | 1,229 | Aug. 23, 2022, 5:02 p.m. |
| Wheatstone Cryptograph — Part 2 | 1,148 | Aug. 13, 2022, 2:58 a.m. |
| M-138 — Part 4 | 1,089 | Aug. 6, 2022, 1:04 a.m. |
| M-138 — Part 3 | 1,089 | Aug. 3, 2022, 2:01 p.m. |
| Modular Sequences | 100 | Aug. 2, 2022, 10:28 p.m. |
| Find the right route — Part 3 | 100 | July 20, 2022, 1:09 a.m. |
| Alberti Challenge — Part 1 | 101 | July 17, 2022, 12:35 a.m. |
| Wheatstone Cryptograph — Part 1 | 100 | July 16, 2022, 1:01 a.m. |
| Find the right route — Part 1 | 100 | July 16, 2022, 12:47 a.m. |
| Double Column Transposition — Part 3 | 1,093 | Oct. 26, 2020, 12:16 a.m. |
| Double Column Transposition — Part 2 | 1,093 | Oct. 25, 2020, 11:07 p.m. |
| Double Column Transposition — Part 4 | 1,093 | Oct. 18, 2020, 6:07 p.m. |
| Double Columnar Transposition | 100 | Oct. 13, 2020, 11:11 p.m. |
| Pigpen with a twist — Part 1 | 100 | Oct. 7, 2020, 10:59 p.m. |
| Playfair Encryption | 100 | Oct. 7, 2020, 2:04 a.m. |
| ADFGVX — Part 2 | 100 | Oct. 7, 2020, 1:07 a.m. |
| ADFGVX — Part 1 | 100 | Oct. 6, 2020, 12:32 a.m. |
| Number Sequence — Part 9 | 100 | Oct. 4, 2020, 1:55 a.m. |
| Advent-Challenge — Part 2 | 1,117 | Oct. 4, 2020, 1:30 a.m. |
| Molehunt (Part 3/3) | 1,083 | Oct. 2, 2020, 12:32 a.m. |
| Molehunt (Part 2/3) | 100 | Oct. 1, 2020, 11:01 p.m. |
| An Invisible Message | 100 | Oct. 1, 2020, 10:36 p.m. |
| Molehunt (Part 1/3) | 100 | Oct. 1, 2020, 12:34 a.m. |
| Advent Challenge — Part 4 | 1,118 | Sept. 29, 2020, 11:10 p.m. |
| Advent Challenge — Part 3 | 1,118 | Sept. 28, 2020, 1:12 a.m. |
| Turing Bombe Enigma I | 100 | Sept. 27, 2020, 4:06 p.m. |
| The Einstein Enigma | 1,119 | Sept. 27, 2020, 3:25 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | Sept. 27, 2020, 1:15 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | Sept. 27, 2020, 1:03 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | Sept. 27, 2020, 1:25 a.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | Sept. 27, 2020, 1:24 a.m. |
| Enigma Part 2 | 1,083 | Sept. 26, 2020, 5:55 p.m. |
| Polyhomophonic Substitution — Part 1 | 101 | Sept. 21, 2020, 12:29 a.m. |
| Autokey Cipher | 100 | Sept. 20, 2020, 3:34 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Sept. 19, 2020, 2:53 p.m. |
| Classical Ciphers^3 | 100 | Sept. 4, 2020, 1:26 a.m. |
| Nils away on travel | 100 | Sept. 3, 2020, 12:34 a.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | Sept. 2, 2020, 11:54 p.m. |
| Enigma Part 1 | 1,083 | Sept. 2, 2020, 11:53 p.m. |
| Hybrid Encryption I | 1,083 | Sept. 1, 2020, 10:12 p.m. |
| How do you become a big cryptographer? | 100 | Sept. 1, 2020, 12:38 a.m. |
| Advent-Challenge — Part 1 | 100 | Aug. 31, 2020, 11:22 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Aug. 31, 2020, 11:04 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Aug. 31, 2020, 11 p.m. |
| One-Time Pad with Flaws | 100 | Aug. 30, 2020, 3:23 p.m. |
| Modified Caesar Cipher | 100 | Aug. 28, 2020, 12:28 a.m. |
| Lightweight Introduction to Lattices — Part 3 | 1,305 | Aug. 26, 2020, 1:34 a.m. |
| Lightweight Introduction to Lattices — Part 2 | 102 | Aug. 26, 2020, 1:24 a.m. |
| Lightweight Introduction to Lattices — Part 1 | 101 | Aug. 24, 2020, 10:54 p.m. |
| Grille Cipher | 100 | Aug. 24, 2020, 1:50 a.m. |
| Snow White and the seven dwarfs | 100 | Aug. 24, 2020, 1:24 a.m. |
| Factorization Cipher — Part 3 | 1,086 | Aug. 23, 2020, 11:48 p.m. |
| Factorization Cipher — Part 2 | 1,086 | Aug. 21, 2020, 1:14 p.m. |
| Factorization Cipher — Part 1 | 100 | Aug. 19, 2020, 8:38 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Aug. 17, 2020, 5:46 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,086 | Aug. 17, 2020, 5:13 p.m. |
| Flawed Usage of a OTP Cipher by the BND | 1,100 | Aug. 16, 2020, 5:37 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Aug. 14, 2020, 9:40 a.m. |
| ¿No Hablas Español? No problemo! | 100 | Aug. 13, 2020, 3:31 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,083 | Aug. 13, 2020, 1:37 p.m. |
| Image Noise | 100 | Aug. 12, 2020, 12:16 a.m. |
| From Russia with Love | 100 | Aug. 12, 2020, 12:10 a.m. |
| Hill Cipher with Sudoku Key | 100 | Aug. 10, 2020, 11:37 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,085 | Aug. 10, 2020, 10:17 p.m. |
| Alice's Birthday Party (Part 2) | 1,083 | Aug. 10, 2020, 6:51 p.m. |
| Monoalphabetic Substitution | 100 | Aug. 10, 2020, 2:55 p.m. |
| A hidden word | 100 | Aug. 10, 2020, 12:25 p.m. |
| Alice's Birthday Party (Part 1) | 1,083 | Aug. 10, 2020, 12:12 p.m. |
| Summer Job | 1,126 | Aug. 10, 2020, 1 a.m. |
| Number Sequence — Part 10 | 100 | Aug. 10, 2020, 12:09 a.m. |
| M-138 — Part 2 | 1,097 | Aug. 8, 2020, 2:49 a.m. |
| Number Sequence — Part 6 | 100 | Aug. 8, 2020, 1:17 a.m. |
| M-138 — Part 1 | 100 | Aug. 8, 2020, 12:29 a.m. |
| The Book Code: A Challenge for Bookworms | 100 | Aug. 7, 2020, 6:33 p.m. |
| Number Sequence — Part 8 | 100 | Aug. 7, 2020, 1:40 a.m. |
| Number Sequence — Part 4 | 100 | Aug. 7, 2020, 1:31 a.m. |
| Number Sequence — Part 3 | 100 | Aug. 7, 2020, 1:11 a.m. |
| Trifid Cipher | 100 | Aug. 5, 2020, 10:39 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,083 | Aug. 3, 2020, 10:41 p.m. |
| Letter to the Templars — Part 2 | 100 | Aug. 3, 2020, 1:17 a.m. |
| Letter to the Templars — Part 1 | 100 | Aug. 3, 2020, 1:12 a.m. |
| Beaver Code | 100 | Aug. 3, 2020, 1:02 a.m. |
| Number Sequence — Part 2 | 100 | Aug. 3, 2020, 12:30 a.m. |
| Caesar Encryption | 100 | Aug. 3, 2020, 12:24 a.m. |
| Original Caesar Cipher | 100 | Aug. 2, 2020, 11:35 p.m. |
| Letter to the Templars — Part 3 | 1,089 | Aug. 2, 2020, 7:06 p.m. |
| Cracking SHA1-Hashed Passwords | 1,084 | Aug. 2, 2020, 6:26 p.m. |
| Number Sequence | 100 | Aug. 2, 2020, 6:18 p.m. |