| Wheatstone Cryptograph — Part 1 | 103 | May 26, 2021, 5:34 p.m. |
| Polyhomophonic Substitution — Part 3 | 1,284 | May 27, 2020, 3:29 p.m. |
| Polyhomophonic Substitution — Part 2 | 1,270 | May 26, 2020, 7:48 p.m. |
| Polyhomophonic Substitution — Part 1 | 102 | May 24, 2020, 6:25 p.m. |
| Number Sequence — Part 10 | 100 | May 18, 2019, 10:10 p.m. |
| Number Sequence — Part 9 | 100 | May 18, 2019, 9:53 p.m. |
| Number Sequence — Part 6 | 100 | May 18, 2019, 9:48 p.m. |
| Modular Sequences | 100 | May 18, 2019, 8:34 p.m. |
| Autokey Cipher | 100 | May 17, 2019, 4:43 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 101 | May 17, 2019, 4:29 p.m. |
| The Vatican Challenge — Part 2 | 2,000 | March 20, 2018, 3:45 p.m. |
| The Vatican Challenge — Part 1 | 1,000 | March 20, 2018, 2:59 p.m. |
| Advent-Challenge — Part 1 | 101 | March 20, 2018, 12:48 p.m. |
| The Einstein Enigma | 1,305 | March 20, 2018, 11:27 a.m. |
| Number Sequence — Part 5 | 100 | Dec. 16, 2016, 5:46 p.m. |
| Kaskade-S/T — Part 2 | 1,097 | Sept. 23, 2016, 2:02 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | Sept. 21, 2016, 9:29 p.m. |
| ADFGVX — Part 1 | 100 | Sept. 21, 2016, 1:15 p.m. |
| Kaskade-S/T — Part 1 | 100 | Sept. 20, 2016, 9:50 p.m. |
| Smartcard RSA | 1,096 | Sept. 20, 2016, 8:09 a.m. |
| The Book Code: A Challenge for Bookworms | 100 | Sept. 18, 2016, 10:27 p.m. |
| Snow White and the seven dwarfs | 100 | Sept. 18, 2016, 7:22 p.m. |
| Number Sequence — Part 7 | 100 | Sept. 18, 2016, 6:57 p.m. |
| A really long number sequence | 1,100 | Sept. 17, 2016, 5:53 p.m. |
| Molehunt (Part 3/3) | 1,096 | Sept. 16, 2016, 3:42 p.m. |
| Molehunt (Part 2/3) | 100 | Sept. 16, 2016, 3:41 p.m. |
| Molehunt (Part 1/3) | 100 | Sept. 16, 2016, 3:41 p.m. |
| ¿No Hablas Español? No problemo! | 100 | Sept. 15, 2016, 9:27 p.m. |
| Multilingual Monoalphabetic Substitution | 100 | Sept. 15, 2016, 3:36 p.m. |
| Pigpen with a twist — Part 3 | 1,100 | Sept. 14, 2016, 10:23 p.m. |
| Pigpen with a twist — Part 2 | 1,100 | Sept. 14, 2016, 10:22 p.m. |
| Ku Klux Klan | 1,000 | Sept. 10, 2016, 11:08 p.m. |
| Monoalphabetic Substitution with Camouflage — Part 5 | 1,103 | Sept. 9, 2016, 1:10 p.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | Sept. 6, 2016, 10:48 a.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,101 | Sept. 5, 2016, 9:03 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,101 | Sept. 5, 2016, 5:12 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Sept. 5, 2016, 9:22 a.m. |
| M-138 — Part 4 | 1,135 | Aug. 30, 2016, 8:44 p.m. |
| Turing Bombe Enigma I | 100 | Aug. 27, 2016, 10:39 p.m. |
| Enigma Combinatorics | 100 | Aug. 27, 2016, 7:22 p.m. |
| Enigma Part 2 | 1,096 | Aug. 23, 2016, 8:39 p.m. |
| Enigma Part 1 | 1,096 | Aug. 23, 2016, 6:47 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | Aug. 22, 2016, 4:19 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | Aug. 22, 2016, 3:19 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | Aug. 22, 2016, 3:11 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | Aug. 22, 2016, 2:14 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | Aug. 22, 2016, 8:51 a.m. |
| Unconcealed RSA messages | 1,101 | Aug. 10, 2016, 10:42 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,096 | Aug. 1, 2016, 8:50 p.m. |
| Playfair with hints about the grid | 100 | Aug. 1, 2016, 5:46 p.m. |
| Hybrid Encryption I | 1,096 | Aug. 1, 2016, 3:19 p.m. |
| Trifid Cipher | 100 | July 31, 2016, 10:47 p.m. |
| M-138 — Part 3 | 1,137 | July 31, 2016, 3:53 p.m. |
| M-138 — Part 2 | 1,137 | July 31, 2016, 3:51 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,096 | July 31, 2016, 11:23 a.m. |
| Number Sequence — Part 8 | 100 | July 30, 2016, 2:51 p.m. |
| Classical Ciphers^3 | 100 | July 28, 2016, 8:55 a.m. |
| M-138 — Part 1 | 100 | July 20, 2016, 11:32 p.m. |
| The Last Note | 100 | July 19, 2016, 9:40 p.m. |
| Cracking SHA1-Hashed Passwords | 1,098 | July 19, 2016, 7:18 a.m. |
| Music Code — Part 2 | 1,099 | July 17, 2016, 10:45 p.m. |
| Music Code — Part 1 | 100 | July 17, 2016, 10:43 p.m. |
| ADFGVX — Part 2 | 100 | July 16, 2016, 7:31 p.m. |
| Enigma Messages | 100 | July 16, 2016, 4:50 p.m. |
| Nils away on travel | 100 | July 16, 2016, 4:32 p.m. |
| News from Castle Mansfeld | 100 | July 15, 2016, 10:36 p.m. |
| A Secret Message from Castle Mansfeld | 100 | July 15, 2016, 10:35 p.m. |
| Double Column Transposition — Part 4 | 1,126 | July 15, 2016, 9:05 p.m. |
| A hidden word — Part 2 | 100 | July 15, 2016, 5:09 p.m. |
| Double Columnar Transposition | 100 | July 15, 2016, 4:55 p.m. |
| Concealed Messages — Vigenère's Night Sky | 1,105 | July 15, 2016, 12:39 p.m. |
| Playfair Encryption | 100 | July 12, 2016, 10:45 a.m. |
| Factorization Cipher — Part 3 | 1,103 | July 12, 2016, 10:34 a.m. |
| How do you become a big cryptographer? | 100 | July 11, 2016, 8:24 a.m. |
| Pigpen with a twist — Part 1 | 100 | July 10, 2016, 9:27 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,104 | July 10, 2016, 8:28 p.m. |
| Factorization Cipher — Part 2 | 1,102 | July 10, 2016, 6:50 p.m. |
| Modified Caesar Cipher | 100 | July 8, 2016, 4:35 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | July 8, 2016, 3:54 p.m. |
| From Russia with Love | 100 | July 7, 2016, 10:39 p.m. |
| One-Time Pad with Flaws | 100 | July 7, 2016, 7:54 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | July 7, 2016, 4:58 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | July 7, 2016, 8:22 a.m. |
| Grille Cipher | 100 | July 7, 2016, 8:14 a.m. |
| Factorization Cipher — Part 1 | 100 | July 6, 2016, 8:17 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | July 6, 2016, 8:06 p.m. |
| A hidden word | 100 | July 6, 2016, 8:02 p.m. |
| Monoalphabetic Substitution | 100 | July 6, 2016, 7:57 p.m. |
| Number Sequence — Part 4 | 100 | July 6, 2016, 7:03 p.m. |
| Number Sequence — Part 3 | 100 | July 6, 2016, 6:04 p.m. |
| Beaver Code | 100 | July 6, 2016, 5:08 p.m. |
| RSA: Two different keys — same ciphertext | 1,101 | July 6, 2016, 4:57 p.m. |
| Caesar Encryption | 100 | July 6, 2016, 10:11 a.m. |
| Broadcasting and low exponent — RSA Attack | 1,100 | July 6, 2016, 8:58 a.m. |
| Number Sequence — Part 2 | 100 | July 6, 2016, 8:13 a.m. |
| Letter to the Templars — Part 2 | 100 | July 6, 2016, 7:54 a.m. |
| Original Caesar Cipher | 100 | July 6, 2016, 7:51 a.m. |
| Letter to the Templars — Part 1 | 100 | July 6, 2016, 7:46 a.m. |
| Letter to the Templars — Part 3 | 1,108 | July 6, 2016, 7:42 a.m. |
| Alice's Birthday Party (Part 2) | 1,096 | July 5, 2016, 10:32 p.m. |
| Alice's Birthday Party (Part 1) | 1,096 | July 5, 2016, 7:30 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Jan. 18, 2016, 9:12 p.m. |
| Image Noise | 102 | Jan. 12, 2016, 10:20 a.m. |
| Number Sequence | 100 | Jan. 12, 2016, 10:11 a.m. |