| Typex — Part 1 | 1,082 | Sept. 11, 2023, 4:14 p.m. |
| New Year's Greetings — Part 1 | 100 | Aug. 14, 2023, 12:05 a.m. |
| Keyshanc — Part 2 | 1,080 | Aug. 8, 2023, 4:23 p.m. |
| Keyshanc — Part 1 | 1,080 | Aug. 8, 2023, 4:39 a.m. |
| A Cloaked Substitution Cipher — Part 2 | 1,107 | July 29, 2023, 11:21 p.m. |
| A Cloaked Substitution Cipher — Part 1 | 1,107 | July 29, 2023, 7:02 a.m. |
| Enigma Part 1 | 1,078 | July 21, 2023, 9:54 p.m. |
| Factorization Cipher — Part 3 | 1,080 | July 21, 2023, 7:20 p.m. |
| BCR code (Book-Caesar-RSA) | 1,081 | July 20, 2023, 2:09 a.m. |
| Double Column Transposition — Part 2 | 1,085 | July 19, 2023, 1:46 a.m. |
| Double Column Transposition — Part 1 | 1,084 | July 19, 2023, 12:32 a.m. |
| Number Sequence — Part 7 | 100 | July 14, 2023, 12:13 a.m. |
| News from Castle Mansfeld | 100 | July 13, 2023, 11:40 p.m. |
| Smartcard RSA | 1,078 | July 13, 2023, 6:33 a.m. |
| A hidden word | 100 | July 10, 2023, 7:18 p.m. |
| ADFGVX — Part 2 | 100 | July 10, 2023, 2:41 a.m. |
| "The Road" — Part 2 | 1,102 | July 8, 2023, 10:04 p.m. |
| "The Road" — Part 1 | 1,103 | June 29, 2023, 3:08 a.m. |
| Number Sequence — Part 5 | 100 | June 23, 2023, 6:05 p.m. |
| Modular Sequences | 100 | June 23, 2023, 4:57 p.m. |
| Unusual encryption using a diophantine equation | 1,079 | June 22, 2023, 12:54 a.m. |
| The Syllabary Cipher – Part 5 | 1,179 | June 19, 2023, 10:35 p.m. |
| The Syllabary Cipher – Part 4 | 1,179 | June 19, 2023, 9:27 p.m. |
| The Syllabary Cipher – Part 3 | 1,179 | June 19, 2023, 2:48 a.m. |
| The Hutton Cipher – Part 2 | 1,523 | June 13, 2023, 12:17 a.m. |
| The Hutton Cipher – Part 1 | 1,305 | June 12, 2023, 3:17 p.m. |
| The Syllabary Cipher – Part 2 | 1,433 | Nov. 10, 2022, 5:32 p.m. |
| Merkle-Hellman Knapsack Challenge - Part 1 | 105 | Nov. 5, 2022, 1:26 a.m. |
| The Syllabary Cipher – Part 1 | 200 | Oct. 28, 2022, 4:06 p.m. |
| Merkle-Hellman Knapsack Challenge — Part 2 | 1,469 | Oct. 24, 2022, 11:24 p.m. |
| Alberti Challenge — Part 1 | 100 | Oct. 14, 2022, 12:38 a.m. |
| Flawed Usage of a OTP Cipher by the BND | 1,096 | June 24, 2021, 2:19 a.m. |
| Hill Cipher with Sudoku Key | 100 | June 9, 2021, 10:34 p.m. |
| Lightweight Introduction to Lattices — Part 1 | 100 | June 2, 2021, 12:31 a.m. |
| How do you become a big cryptographer? | 100 | May 30, 2021, 7:04 p.m. |
| Polyhomophonic Substitution — Part 3 | 1,151 | May 29, 2021, 7:54 p.m. |
| Cascading Encryption — Part 2/3 | 1,087 | May 28, 2021, 4:47 a.m. |
| The LoRa Cipher: Logic Randomness — Part 1 | 1,147 | May 26, 2021, 3:14 a.m. |
| Polyhomophonic Substitution — Part 2 | 1,151 | May 25, 2021, 5:04 a.m. |
| Polyphonic Substitution Cipher — Part 2 | 1,144 | May 24, 2021, 12:45 a.m. |
| Polyphonic Substitution Cipher — Part 1 | 1,140 | May 23, 2021, 11:37 p.m. |
| AES ECB Wrong Encoding | 1,111 | May 21, 2021, 1:31 a.m. |
| Homophonic Encryption — Part 4 | 1,129 | May 19, 2021, 3:49 a.m. |
| Homophonic Encryption — Part 2 | 1,129 | May 19, 2021, 2:48 a.m. |
| Homophonic Encryption — Part 1 | 1,128 | May 19, 2021, 2:37 a.m. |
| Homophonic Encryption — Part 3 | 1,129 | May 19, 2021, 2:13 a.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | May 19, 2021, 12:35 a.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | May 19, 2021, 12:03 a.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | May 18, 2021, 11:17 p.m. |
| Advent Challenge — Part 3 | 1,111 | May 18, 2021, 6:53 p.m. |
| Spanish Strip Cipher — Part 2 | 1,091 | May 18, 2021, 2:51 a.m. |
| Ku Klux Klan | 1,000 | May 17, 2021, 3:27 p.m. |
| Lightweight Introduction to Lattices — Part 3 | 1,166 | May 17, 2021, 3:53 a.m. |
| Find the right route — Part 3 | 101 | May 15, 2021, 10:53 p.m. |
| Find the right route — Part 2 | 101 | May 13, 2021, 5:33 a.m. |
| RSA Factoring Challenge: RSA-230 | 0 | May 13, 2021, 3:23 a.m. |
| RSA Factoring Challenge: RSA-220 | 0 | May 13, 2021, 3:22 a.m. |
| RSA Factoring Challenge: RSA-704 | 0 | May 13, 2021, 3:20 a.m. |
| RSA Factoring Challenge: RSA-210 | 0 | May 13, 2021, 3:18 a.m. |
| RSA Factoring Challenge: RSA-250 | 0 | May 13, 2021, 3:15 a.m. |
| RSA Factoring Challenge: RSA-232 | 0 | May 13, 2021, 3:11 a.m. |
| RSA Factoring Challenge: RSA-240 | 0 | May 13, 2021, 3:07 a.m. |
| Polyhomophonic Substitution — Part 1 | 100 | May 11, 2021, 5:26 a.m. |
| Weakened Granit — Part 1 | 100 | May 10, 2021, 12:28 a.m. |
| Nils away on travel | 100 | May 9, 2021, 2:27 a.m. |
| Spanish Strip Cipher — Part 1 | 1,091 | May 8, 2021, 4:20 a.m. |
| Number Sequence — Part 10 | 100 | May 7, 2021, 8:44 p.m. |
| Number Sequence — Part 9 | 100 | May 7, 2021, 5:57 p.m. |
| Number Sequence — Part 6 | 100 | May 7, 2021, 5:23 p.m. |
| Image Noise | 100 | May 7, 2021, 12:11 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | May 6, 2021, 3:35 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | May 6, 2021, 3:07 a.m. |
| Zodiac Cipher | 100 | May 5, 2021, 11:43 p.m. |
| Turing Bombe Enigma I | 100 | May 5, 2021, 7:39 p.m. |
| M-138 — Part 4 | 1,094 | May 5, 2021, 5:08 a.m. |
| Double Column Transposition — Part 4 | 1,091 | May 2, 2021, 5:59 a.m. |
| Enigma Part 2 | 1,082 | May 1, 2021, 7:40 p.m. |
| Find the right route — Part 1 | 101 | April 30, 2021, 1:16 a.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | April 30, 2021, 12:04 a.m. |
| Pigpen with a twist — Part 2 | 1,084 | April 29, 2021, 11:42 p.m. |
| Factorization Cipher — Part 2 | 1,084 | April 22, 2021, 9:54 p.m. |
| Wheatstone Cryptograph — Part 1 | 200 | April 22, 2021, 6:01 a.m. |
| Molehunt (Part 3/3) | 1,082 | April 22, 2021, 3:10 a.m. |
| Monoalphabetic Substitution with Nostradamus Flavor | 1,126 | April 21, 2021, 10:27 p.m. |
| Autokey Cipher | 100 | Oct. 26, 2019, 1:36 a.m. |
| Pigpen with a twist — Part 3 | 1,092 | July 7, 2018, 4:05 p.m. |
| A really long number sequence | 1,092 | June 27, 2018, 11:59 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,094 | June 27, 2018, 2:17 a.m. |
| Advent Challenge — Part 4 | 1,192 | June 24, 2018, 9:14 p.m. |
| Trendy Messenger | 1,469 | June 22, 2018, 4:47 p.m. |
| Summer Job | 1,485 | June 22, 2018, 4:38 a.m. |
| Fastest in the West | 1,485 | June 21, 2018, 6:56 p.m. |
| M-138 — Part 3 | 1,111 | June 19, 2018, 1:35 a.m. |
| Enigma Combinatorics | 100 | June 8, 2018, 5:18 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | June 7, 2018, 10:51 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | June 7, 2018, 1:33 a.m. |
| Enigma Messages | 100 | June 3, 2018, 2:31 a.m. |
| Strange Message from Thessaloniki | 100 | June 1, 2018, 2:23 a.m. |
| Recycled One-Time Pad | 100 | May 31, 2018, 1:41 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | May 30, 2018, 4:03 a.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | May 30, 2018, 3:55 a.m. |
| Trifid Cipher | 100 | May 29, 2018, 5:55 p.m. |
| RSA: Two different keys — same ciphertext | 1,092 | May 29, 2018, 12:37 a.m. |
| A hidden word — Part 2 | 100 | May 28, 2018, 10:37 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | May 28, 2018, 8:40 p.m. |
| Cascading Encryption — Part 1/3 | 100 | May 28, 2018, 4:53 p.m. |
| The Einstein Enigma | 1,224 | May 28, 2018, 2:56 a.m. |
| ECDH-Key Exchange for Beginners | 100 | May 27, 2018, 10:10 p.m. |
| Kaskade-S/T — Part 1 | 100 | May 26, 2018, 10:51 p.m. |
| Molehunt (Part 2/3) | 100 | May 26, 2018, 1:56 a.m. |
| The Last Note | 100 | May 26, 2018, 1:39 a.m. |
| Hybrid Encryption I | 1,089 | May 25, 2018, 3:13 a.m. |
| Reserve Hand Procedure — Part 1 | 100 | May 25, 2018, 12:45 a.m. |
| Snow White and the seven dwarfs | 100 | May 24, 2018, 10:19 p.m. |
| M-138 — Part 2 | 1,111 | May 24, 2018, 2:20 a.m. |
| M-138 — Part 1 | 100 | May 23, 2018, 4:41 a.m. |
| ¿No Hablas Español? No problemo! | 100 | May 23, 2018, 4 a.m. |
| A Secret Message from Castle Mansfeld | 100 | May 23, 2018, 3:24 a.m. |
| The Book Code: A Challenge for Bookworms | 100 | May 23, 2018, 2:06 a.m. |
| Playfair with hints about the grid | 100 | May 22, 2018, 2:41 a.m. |
| Playfair Encryption | 100 | May 22, 2018, 2:33 a.m. |
| Pigpen with a twist — Part 1 | 100 | May 21, 2018, 4:24 p.m. |
| Multilingual Monoalphabetic Substitution | 100 | May 20, 2018, 9:46 p.m. |
| Double Column Transposition — Part 3 | 1,106 | May 20, 2018, 5:26 p.m. |
| Molehunt (Part 1/3) | 100 | May 20, 2018, 5:11 a.m. |
| Double Columnar Transposition | 100 | May 19, 2018, 11:51 p.m. |
| Advent-Challenge — Part 1 | 101 | May 19, 2018, 6:18 p.m. |
| Classical Ciphers^3 | 100 | May 19, 2018, 5:02 p.m. |
| Modified Caesar Cipher | 100 | May 18, 2018, 8:52 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,089 | May 17, 2018, 9:56 p.m. |
| ADFGVX — Part 1 | 100 | May 17, 2018, 8:47 p.m. |
| Caesar Encryption | 100 | May 17, 2018, 7:40 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,092 | May 17, 2018, 2:45 a.m. |
| Alice's Birthday Party (Part 2) | 1,089 | May 17, 2018, 2:15 a.m. |
| Alice's Birthday Party (Part 1) | 1,089 | May 17, 2018, 12:19 a.m. |
| One-Time Pad with Flaws | 100 | May 16, 2018, 3:48 p.m. |
| Number Sequence — Part 8 | 100 | May 16, 2018, 3:08 a.m. |
| From Russia with Love | 100 | May 16, 2018, 3:01 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | May 16, 2018, 1:52 a.m. |
| Grille Cipher | 100 | May 15, 2018, 11 p.m. |
| Factorization Cipher — Part 1 | 100 | May 15, 2018, 10:24 p.m. |
| Monoalphabetic Substitution | 100 | May 15, 2018, 8:26 p.m. |
| Letter to the Templars — Part 3 | 1,097 | May 15, 2018, 2:04 a.m. |
| Letter to the Templars — Part 2 | 100 | May 15, 2018, 1:22 a.m. |
| Cracking SHA1-Hashed Passwords | 1,091 | May 15, 2018, 12:55 a.m. |
| Letter to the Templars — Part 1 | 100 | May 15, 2018, 12:52 a.m. |
| Number Sequence — Part 3 | 100 | May 14, 2018, 9:22 p.m. |
| Number Sequence — Part 4 | 100 | May 14, 2018, 9:18 p.m. |
| Beaver Code | 100 | May 14, 2018, 9:11 p.m. |
| Number Sequence — Part 2 | 100 | May 14, 2018, 8:27 p.m. |
| Number Sequence | 100 | May 14, 2018, 8:20 p.m. |
| Original Caesar Cipher | 100 | May 14, 2018, 7:56 p.m. |
Gold0
Silver1
Bronze0
