| The Hutton Cipher – Part 1 | 2,000 | May 2, 2023, 7:28 p.m. |
| The Josse Challenge – Part 3 | 2,000 | March 27, 2023, 1:34 p.m. |
| The Josse Challenge – Part 2 | 2,000 | Feb. 25, 2023, 3:32 p.m. |
| Flawed Usage of a OTP Cipher by the BND | 1,090 | Feb. 19, 2023, 1:40 a.m. |
| The Josse Challenge – Part 1 | 1,547 | Feb. 17, 2023, 3:42 a.m. |
| The Syllabary Cipher – Part 5 | 1,547 | Nov. 4, 2022, 1:59 a.m. |
| The Syllabary Cipher – Part 3 | 1,576 | Nov. 2, 2022, 4:40 p.m. |
| The Syllabary Cipher – Part 4 | 1,613 | Nov. 1, 2022, 4:56 p.m. |
| The Syllabary Cipher – Part 2 | 1,660 | Nov. 1, 2022, 11:15 a.m. |
| The Syllabary Cipher – Part 1 | 200 | Oct. 29, 2022, 1:14 a.m. |
| Hill Cipher | 1,286 | Oct. 23, 2022, 7:20 p.m. |
| Merkle-Hellman Knapsack Challenge — Part 2 | 1,576 | Oct. 19, 2022, 10:31 p.m. |
| Merkle-Hellman Knapsack Challenge - Part 1 | 117 | Oct. 19, 2022, 8:33 p.m. |
| Modified Vigenère Cipher | 1,183 | Aug. 29, 2022, 10:02 p.m. |
| The Einstein Enigma | 1,103 | Aug. 27, 2022, 6:46 p.m. |
| New Year's Greetings — Part 4 | 100 | Aug. 26, 2022, 2:46 a.m. |
| New Year's Greetings — Part 3 | 100 | Aug. 26, 2022, 2:35 a.m. |
| New Year's Greetings — Part 2 | 100 | Aug. 26, 2022, 2:13 a.m. |
| New Year's Greetings — Part 1 | 100 | Aug. 26, 2022, 2:02 a.m. |
| Image Noise | 100 | Aug. 26, 2022, 1:48 a.m. |
| Kaskade-S/T — Part 3 | 1,080 | Aug. 21, 2022, 3:52 p.m. |
| Kaskade-S/T — Part 2 | 1,080 | Aug. 21, 2022, 4:02 a.m. |
| Alberti Challenge — Part 2 | 1,237 | Aug. 13, 2022, 11:44 p.m. |
| Alberti Challenge — Part 1 | 101 | Aug. 13, 2022, 4:38 a.m. |
| Number Sequence — Part 9 | 100 | June 20, 2021, 2:48 a.m. |
| Number Sequence — Part 7 | 100 | June 20, 2021, 2:33 a.m. |
| Number Sequence — Part 6 | 100 | June 20, 2021, 2:22 a.m. |
| Handycipher made in love — Part 2 | 1,128 | June 17, 2021, 6:13 p.m. |
| Handycipher made in love — Part 1 | 1,124 | June 17, 2021, 4:01 a.m. |
| Lightweight Introduction to Lattices — Part 3 | 1,162 | June 13, 2021, 2:07 a.m. |
| Lightweight Introduction to Lattices — Part 2 | 100 | June 13, 2021, 1:32 a.m. |
| Lightweight Introduction to Lattices — Part 1 | 100 | June 13, 2021, 1:13 a.m. |
| Unconcealed RSA messages | 1,084 | May 16, 2021, 10:05 p.m. |
| CMEA 1 | 1,082 | April 24, 2021, 4:34 p.m. |
| A really long number sequence | 1,084 | April 24, 2021, 3:16 p.m. |
| Number Sequence — Part 10 | 100 | April 23, 2021, 4:41 a.m. |
| Number Sequence — Part 5 | 100 | April 23, 2021, 3:47 a.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,082 | April 17, 2021, 8:59 p.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,085 | April 17, 2021, 7:15 p.m. |
| Double Column Transposition — Part 4 | 1,092 | April 13, 2021, 12:31 a.m. |
| Double Column Transposition — Part 3 | 1,091 | April 12, 2021, 4:01 p.m. |
| Double Column Transposition — Part 2 | 1,091 | April 12, 2021, 3:42 p.m. |
| Double Column Transposition — Part 1 | 1,091 | April 12, 2021, 4:34 a.m. |
| Not-so-Secret Message from Malawi — Part II (ECC) | 1,082 | April 10, 2021, 6:06 p.m. |
| Advent Challenge — Part 4 | 1,113 | Feb. 26, 2021, 3:22 a.m. |
| Advent Challenge — Part 3 | 1,113 | Feb. 26, 2021, 3:03 a.m. |
| Advent-Challenge — Part 2 | 1,113 | Feb. 26, 2021, 12:19 a.m. |
| Spanish Strip Cipher — Part 1 | 1,092 | Feb. 25, 2021, 3:01 a.m. |
| Molehunt (Part 3/3) | 1,082 | Feb. 24, 2021, 5:05 a.m. |
| Molehunt (Part 1/3) | 100 | Feb. 23, 2021, 1:48 a.m. |
| Find the right route — Part 3 | 102 | Feb. 18, 2021, 2:35 a.m. |
| Find the right route — Part 2 | 102 | Feb. 17, 2021, 7 a.m. |
| Find the right route — Part 1 | 101 | Feb. 17, 2021, 6:13 a.m. |
| ADFGVX — Part 2 | 100 | Feb. 17, 2021, 5:15 a.m. |
| ADFGVX — Part 1 | 100 | Feb. 17, 2021, 4:49 a.m. |
| Trendy Messenger | 1,131 | April 27, 2020, 4:40 p.m. |
| Breaking a Filter Generator | 1,138 | April 27, 2020, 1:55 p.m. |
| Summer Job | 1,132 | April 21, 2020, 3:46 a.m. |
| Pigpen with a twist — Part 3 | 1,086 | March 31, 2020, 5:16 p.m. |
| Snow White and the seven dwarfs | 100 | March 31, 2020, 1:07 a.m. |
| Nils away on travel | 100 | March 30, 2020, 4:30 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | March 26, 2020, 2:55 a.m. |
| Number Sequence — Part 3 | 100 | March 24, 2020, 8:56 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | March 22, 2020, 1:38 a.m. |
| Multilingual Monoalphabetic Substitution | 100 | March 21, 2020, 6:54 a.m. |
| Recycled One-Time Pad | 100 | March 21, 2020, 5:33 a.m. |
| Unusual encryption using a diophantine equation | 1,086 | March 11, 2020, 10:21 p.m. |
| Number Sequence — Part 8 | 100 | March 11, 2020, 5:11 a.m. |
| Number Sequence — Part 4 | 100 | March 11, 2020, 4:48 a.m. |
| Trifid Cipher | 100 | March 10, 2020, 3:46 p.m. |
| Polyphonic Substitution Cipher — Part 1 | 1,226 | March 7, 2020, 6:57 p.m. |
| Polyphonic Substitution Cipher — Part 2 | 1,281 | March 7, 2020, 1:38 p.m. |
| Cascading Encryption — Part 1/3 | 100 | March 4, 2020, 7:44 a.m. |
| Molehunt (Part 2/3) | 100 | Feb. 29, 2020, 6:14 a.m. |
| Kaskade-S/T — Part 1 | 100 | Feb. 28, 2020, 7:20 p.m. |
| Fastest in the West | 1,135 | Feb. 28, 2020, 5:56 p.m. |
| AES ECB Wrong Encoding | 1,126 | Feb. 28, 2020, 5:34 p.m. |
| Keyshanc — Part 2 | 1,089 | Feb. 28, 2020, 4:56 p.m. |
| Keyshanc — Part 1 | 1,089 | Feb. 28, 2020, 3:51 p.m. |
| Cipher ID — Part 1 | 1,230 | Feb. 27, 2020, 11:03 p.m. |
| A Cloaked Substitution Cipher — Part 2 | 1,192 | Feb. 25, 2020, 12:03 a.m. |
| Typex — Part 2 | 1,092 | Feb. 24, 2020, 11:45 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Feb. 24, 2020, 8:05 a.m. |
| The LoRa Cipher: Logic Randomness — Part 1 | 2,000 | Feb. 20, 2020, 4:41 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | Feb. 20, 2020, 5:15 a.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,084 | Feb. 20, 2020, 3:25 a.m. |
| Hybrid Encryption I | 1,084 | Feb. 20, 2020, 12:41 a.m. |
| A Cloaked Substitution Cipher — Part 1 | 1,193 | Feb. 19, 2020, 4:28 a.m. |
| Monoalphabetic Substitution with Camouflage — Part 5 | 1,088 | Feb. 18, 2020, 3:20 a.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | Feb. 18, 2020, 2:33 a.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,087 | Feb. 18, 2020, 12:53 a.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,087 | Feb. 18, 2020, 12:04 a.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Feb. 17, 2020, 8:48 p.m. |
| Enigma Combinatorics | 100 | Feb. 17, 2020, 2:54 a.m. |
| Zodiac Cipher | 100 | Feb. 16, 2020, 5:51 a.m. |
| Enigma Messages | 100 | Feb. 12, 2020, 7:22 a.m. |
| Enigma Part 2 | 1,084 | Feb. 12, 2020, 6:33 a.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | Feb. 11, 2020, 5:25 a.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | Feb. 11, 2020, 1:56 a.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | Feb. 11, 2020, 12:23 a.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | Feb. 11, 2020, 12:09 a.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | Feb. 10, 2020, 11:42 p.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,085 | Feb. 10, 2020, 11:27 p.m. |
| Homophonic Encryption — Part 2 | 1,170 | Feb. 10, 2020, 9:13 p.m. |
| Homophonic Encryption — Part 4 | 1,170 | Feb. 10, 2020, 11:37 a.m. |
| Homophonic Encryption — Part 3 | 1,170 | Feb. 10, 2020, 10:31 a.m. |
| Homophonic Encryption — Part 1 | 1,170 | Feb. 10, 2020, 10:30 a.m. |
| Enigma Part 1 | 1,084 | Feb. 10, 2020, 2:30 a.m. |
| Hill Cipher with Sudoku Key | 100 | May 12, 2019, 6:05 p.m. |
| Number Sequence — Part 2 | 100 | April 19, 2019, 4:58 p.m. |
| Number Sequence | 100 | April 19, 2019, 4:54 p.m. |
| The Book Code: A Challenge for Bookworms | 100 | April 7, 2019, 5:55 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,091 | April 7, 2019, 5:52 a.m. |
| RSA: Two different keys — same ciphertext | 1,089 | April 6, 2019, 11:14 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,089 | April 3, 2019, 5:48 a.m. |
| Modified Caesar Cipher | 100 | April 3, 2019, 5:28 a.m. |
| Alice's Birthday Party (Part 2) | 1,087 | April 3, 2019, 4:26 a.m. |
| Alice's Birthday Party (Part 1) | 1,087 | April 3, 2019, 4:05 a.m. |
| A hidden word — Part 2 | 100 | April 3, 2019, 2:33 a.m. |
| Cracking SHA1-Hashed Passwords | 1,088 | April 1, 2019, 7:11 p.m. |
| ECDH-Key Exchange for Beginners | 100 | April 1, 2019, 6:53 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | April 1, 2019, 6:23 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | April 1, 2019, 6 p.m. |
| Double Columnar Transposition | 100 | Feb. 27, 2019, 1:25 p.m. |
| One-Time Pad with Flaws | 100 | Feb. 26, 2019, 1:34 a.m. |
| Grille Cipher | 100 | Feb. 22, 2019, 4:03 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Feb. 22, 2019, 2:27 a.m. |
| Beaver Code | 100 | Feb. 22, 2019, 2:01 a.m. |
| ¿No Hablas Español? No problemo! | 100 | Feb. 21, 2019, 3:57 a.m. |
| How do you become a big cryptographer? | 100 | Feb. 21, 2019, 1:21 a.m. |
| Factorization Cipher — Part 2 | 1,090 | Feb. 19, 2019, 4:36 p.m. |
| An 'unhearable' message | 100 | Feb. 18, 2019, 3:55 p.m. |
| Factorization Cipher — Part 3 | 1,091 | Feb. 15, 2019, 5:20 a.m. |
| Factorization Cipher — Part 1 | 100 | Feb. 15, 2019, 3:17 a.m. |
| Pigpen with a twist — Part 2 | 1,090 | Feb. 14, 2019, 10:10 p.m. |
| Pigpen with a twist — Part 1 | 100 | Feb. 14, 2019, 4:48 p.m. |
| An Invisible Message | 100 | Feb. 14, 2019, 1:03 p.m. |
| Monoalphabetic Substitution | 100 | Feb. 13, 2019, 6:35 a.m. |
| Letter to the Templars — Part 3 | 1,094 | Feb. 13, 2019, 5:37 a.m. |
| Letter to the Templars — Part 2 | 100 | Feb. 13, 2019, 5:22 a.m. |
| Letter to the Templars — Part 1 | 100 | Feb. 13, 2019, 5:07 a.m. |
| Classical Ciphers^3 | 100 | Feb. 13, 2019, 4:47 a.m. |
| A hidden word | 100 | Feb. 12, 2019, 3:29 a.m. |
| Caesar Encryption | 100 | Feb. 11, 2019, 4:29 p.m. |
| Playfair with hints about the grid | 100 | Feb. 11, 2019, 8:11 a.m. |
| Playfair Encryption | 100 | Feb. 11, 2019, 7:45 a.m. |
| Original Caesar Cipher | 100 | Feb. 11, 2019, 7:09 a.m. |
| M-138 — Part 2 | 1,107 | Nov. 15, 2018, 11:12 p.m. |
| From Russia with Love | 100 | Nov. 15, 2018, 12:31 p.m. |
| M-138 — Part 1 | 100 | Nov. 15, 2018, 11:34 a.m. |
| Modular Sequences | 102 | Nov. 15, 2018, 10:59 a.m. |
| Advent-Challenge — Part 1 | 100 | Nov. 15, 2018, 2:40 a.m. |
| Autokey Cipher | 102 | Nov. 15, 2018, 2:30 a.m. |
Gold2
Silver1
Bronze2
