| The Hutton Cipher – Part 1 | 2,000 | May 2, 2023, 7:26 p.m. |
| The Syllabary Cipher – Part 3 | 1,725 | Oct. 30, 2022, 9:57 p.m. |
| The Syllabary Cipher – Part 1 | 200 | Oct. 28, 2022, 7:05 p.m. |
| Merkle-Hellman Knapsack Challenge — Part 2 | 1,725 | Oct. 16, 2022, 7:19 p.m. |
| Merkle-Hellman Knapsack Challenge - Part 1 | 150 | Oct. 16, 2022, 5:14 p.m. |
| Hill Cipher | 1,523 | Sept. 11, 2022, 2:50 p.m. |
| Modified Vigenère Cipher | 1,242 | April 19, 2022, 4:49 p.m. |
| Alberti Challenge — Part 1 | 104 | April 19, 2022, 11:46 a.m. |
| ASAC — A Strong(er) ADFGVX Cipher — Part 1 | 1,101 | May 8, 2021, 4:25 p.m. |
| Wheatstone Cryptograph — Part 1 | 125 | April 25, 2021, 12:55 p.m. |
| Find the right route — Part 3 | 200 | Dec. 26, 2020, 7:53 p.m. |
| Find the right route — Part 2 | 200 | Dec. 19, 2020, 8:13 p.m. |
| Find the right route — Part 1 | 200 | Oct. 27, 2020, 5:54 p.m. |
| The SZ42 Challenge — Part 3 | 2,000 | Aug. 16, 2020, 7:10 p.m. |
| The SZ42 Challenge — Part 2 | 2,000 | Aug. 5, 2020, 11:18 p.m. |
| The SZ42 Challenge — Part 1 | 1,613 | July 27, 2020, 2:04 p.m. |
| Lightweight Introduction to Lattices — Part 3 | 2,000 | July 16, 2020, 1:39 p.m. |
| Lightweight Introduction to Lattices — Part 2 | 200 | June 24, 2020, 9:55 a.m. |
| Lightweight Introduction to Lattices — Part 1 | 200 | May 16, 2020, 4:52 p.m. |
| Polyhomophonic Substitution — Part 3 | 2,000 | April 7, 2020, 2:59 p.m. |
| The T52 Sturgeon Challenge — Part 2 | 1,175 | March 30, 2020, 11:52 p.m. |
| Polyhomophonic Substitution — Part 2 | 2,000 | March 29, 2020, 3:46 a.m. |
| The T52 Sturgeon Challenge — Part 4 | 1,176 | March 27, 2020, 3:39 p.m. |
| The T52 Sturgeon Challenge — Part 1 | 1,174 | March 27, 2020, 2:26 p.m. |
| Polyphonic Substitution Cipher — Part 2 | 1,256 | March 24, 2020, 6:22 p.m. |
| Polyphonic Substitution Cipher — Part 1 | 1,216 | March 24, 2020, 5:35 p.m. |
| Polyhomophonic Substitution — Part 1 | 200 | March 22, 2020, 12:48 p.m. |
| The SIGABA Challenge — Part 2 | 1,406 | March 21, 2020, 7:54 p.m. |
| Typex — Part 2 | 1,091 | March 7, 2020, 6:56 p.m. |
| Typex — Part 1 | 1,091 | March 7, 2020, 10 a.m. |
| The SIGABA Challenge — Part 1 | 1,576 | March 6, 2020, 2:41 a.m. |
| The LoRa Cipher: Logic Randomness — Part 1 | 2,000 | Feb. 20, 2020, 4:28 a.m. |
| Differential Cryptanalysis — Part 2 | 2,000 | Jan. 29, 2020, 11:13 a.m. |
| Christmas Challenge 2019: Differential Cryptanalysis — Part 1 | 1,456 | Jan. 3, 2020, 6:30 p.m. |
| Homophonic Encryption — Part 2 | 1,433 | May 22, 2019, 3:21 p.m. |
| Handycipher made in love — Part 2 | 2,000 | May 22, 2019, 3:03 p.m. |
| Homophonic Encryption — Part 4 | 1,444 | May 21, 2019, 6:51 p.m. |
| Homophonic Encryption — Part 3 | 2,000 | May 9, 2019, 1:01 p.m. |
| Homophonic Encryption — Part 1 | 2,000 | May 5, 2019, 3:17 p.m. |
| New Year's Greetings — Part 5 | 1,115 | March 25, 2019, 1:53 p.m. |
| Handycipher made in love — Part 1 | 1,824 | Feb. 17, 2019, 4:28 p.m. |
| Monoalphabetic Substitution with Nostradamus Flavor | 2,000 | Feb. 16, 2019, 7:22 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 200 | Jan. 9, 2019, 4:25 p.m. |
| RSA with Special d | 13,176 | Nov. 12, 2018, 1:03 a.m. |
| Lattice Part 1 | 1,089 | Oct. 30, 2018, 5:28 p.m. |
| Cryptanalysis Hacking Puzzles — Part 1 | 200 | Oct. 27, 2018, 2:30 p.m. |
| Autokey Cipher | 150 | Sept. 27, 2018, 11:50 a.m. |
| Modular Sequences | 150 | Sept. 27, 2018, 11:43 a.m. |
| M-138 — Part 4 | 1,110 | July 17, 2018, 9:55 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,093 | July 17, 2018, 7:54 p.m. |
| Monoalphabetic Substitution with Camouflage — Part 5 | 1,094 | July 17, 2018, 6:28 p.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,093 | July 16, 2018, 1:06 p.m. |
| Hilly — Part 1 | 1,142 | July 3, 2018, 2:17 a.m. |
| Flawed Usage of a OTP Cipher by the BND | 1,117 | June 21, 2018, 11 p.m. |
| Summer Job | 1,725 | June 14, 2018, 10:17 p.m. |
| Fastest in the West | 1,824 | June 14, 2018, 1:22 p.m. |
| Trendy Messenger | 1,824 | June 13, 2018, 2:33 p.m. |
| Number Sequence — Part 10 | 150 | April 19, 2018, 10:11 p.m. |
| Pigpen with a twist — Part 2 | 1,093 | March 23, 2018, 8:18 p.m. |
| The Einstein Enigma | 1,824 | Feb. 9, 2018, 12:33 p.m. |
| AES ECB Wrong Encoding | 1,523 | Dec. 24, 2017, 5:46 p.m. |
| Advent Challenge — Part 3 | 2,000 | Dec. 22, 2017, 7:31 p.m. |
| Advent Challenge — Part 4 | 2,000 | Dec. 22, 2017, 1:43 a.m. |
| Advent-Challenge — Part 2 | 2,000 | Dec. 17, 2017, 6:30 a.m. |
| Advent-Challenge — Part 1 | 133 | Dec. 11, 2017, 4:23 p.m. |
| Number Sequence — Part 9 | 200 | Nov. 17, 2017, 12:20 p.m. |
| Keyshanc — Part 2 | 1,098 | Nov. 2, 2017, 11:07 p.m. |
| Keyshanc — Part 1 | 1,098 | Nov. 2, 2017, 7:49 p.m. |
| Double Column Transposition — Part 3 | 1,115 | May 16, 2017, 8:50 p.m. |
| Double Column Transposition — Part 2 | 1,115 | May 16, 2017, 12:16 a.m. |
| ORYX Stream Cipher Part I | 1,093 | May 7, 2017, 9:58 p.m. |
| BCR code (Book-Caesar-RSA) | 1,102 | May 6, 2017, 7:48 a.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,094 | April 12, 2017, 12:20 a.m. |
| Pigpen with a twist — Part 3 | 1,097 | April 11, 2017, 2:08 a.m. |
| Enigma Part 2 | 1,093 | April 4, 2017, 5:43 p.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | April 4, 2017, 1:29 p.m. |
| Weakened Granit — Part 1 | 100 | April 3, 2017, 6:17 p.m. |
| Turing Bombe Enigma I | 100 | April 3, 2017, 12:08 a.m. |
| The Book Code: A Challenge for Bookworms | 100 | April 2, 2017, 4:59 p.m. |
| Strange Message from Thessaloniki | 100 | April 1, 2017, 11:15 p.m. |
| News from Castle Mansfeld | 100 | April 1, 2017, 8:31 p.m. |
| Zodiac Cipher | 100 | April 1, 2017, 6:03 p.m. |
| Playfair with hints about the grid | 100 | April 1, 2017, 3:35 p.m. |
| Playfair Encryption | 100 | March 31, 2017, 10:04 p.m. |
| Cascading Encryption — Part 1/3 | 100 | March 30, 2017, 10:46 p.m. |
| Multilingual Monoalphabetic Substitution | 100 | March 30, 2017, 8 p.m. |
| Heartbleed — Part 3 | 1,120 | March 30, 2017, 5:43 p.m. |
| A Secret Message from Castle Mansfeld | 100 | March 29, 2017, 4:05 p.m. |
| Music Code — Part 2 | 1,096 | March 29, 2017, 2:08 a.m. |
| Music Code — Part 1 | 100 | March 29, 2017, 2:07 a.m. |
| Double Columnar Transposition | 100 | March 27, 2017, 2:01 p.m. |
| Enigma Part 1 | 1,093 | March 27, 2017, 2:05 a.m. |
| Heartbleed — Part 2 | 100 | March 26, 2017, 11:07 p.m. |
| Heartbleed — Part 1 | 100 | March 26, 2017, 10:01 p.m. |
| Enigma Messages | 100 | March 25, 2017, 1:48 a.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | March 24, 2017, 10:04 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | March 24, 2017, 2:52 a.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | March 23, 2017, 2:12 a.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | March 22, 2017, 7:39 p.m. |
| Kaskade-S/T — Part 2 | 1,095 | March 21, 2017, 4:59 p.m. |
| Kaskade-S/T — Part 1 | 100 | March 21, 2017, 12:39 a.m. |
| An 'unhearable' message | 100 | March 20, 2017, 2:42 p.m. |
| Number Sequence — Part 5 | 100 | March 15, 2017, 12:43 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Feb. 28, 2017, 1:14 p.m. |
| Molehunt (Part 3/3) | 1,094 | Feb. 27, 2017, 11:37 p.m. |
| Molehunt (Part 2/3) | 100 | Feb. 27, 2017, 10:36 p.m. |
| Molehunt (Part 1/3) | 100 | Feb. 27, 2017, 9:56 p.m. |
| Number Sequence — Part 7 | 100 | Feb. 27, 2017, 4:10 p.m. |
| Hill Cipher with Sudoku Key | 100 | Feb. 21, 2017, 12:55 a.m. |
| Nils away on travel | 100 | Oct. 13, 2016, 11:23 p.m. |
| Classical Ciphers^3 | 100 | Oct. 13, 2016, 9:21 p.m. |
| The Last Note | 100 | Oct. 13, 2016, 6:46 p.m. |
| Unusual encryption using a diophantine equation | 1,100 | Oct. 5, 2016, 11:55 p.m. |
| Not-so-Secret Message from Malawi — Part II (ECC) | 1,095 | Oct. 5, 2016, 10:14 p.m. |
| ECDH-Key Exchange for Beginners | 100 | Oct. 2, 2016, 2:52 p.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,102 | Sept. 27, 2016, 8:25 p.m. |
| ADFGVX — Part 2 | 100 | Aug. 14, 2016, 3:50 p.m. |
| ADFGVX — Part 1 | 100 | Aug. 14, 2016, 2:58 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | May 4, 2016, 3:40 p.m. |
| Factorization Cipher — Part 3 | 1,104 | April 26, 2016, 10:14 p.m. |
| New Year's Greetings — Part 4 | 150 | March 22, 2016, 7:14 p.m. |
| New Year's Greetings — Part 3 | 150 | March 22, 2016, 7:10 p.m. |
| New Year's Greetings — Part 2 | 150 | March 22, 2016, 7:01 p.m. |
| New Year's Greetings — Part 1 | 150 | March 22, 2016, 6:45 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | March 20, 2016, 2:47 p.m. |
| Pigpen with a twist — Part 1 | 100 | March 20, 2016, 2:34 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | March 19, 2016, 11:58 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | March 19, 2016, 6:28 p.m. |
| Modified Caesar Cipher | 100 | March 19, 2016, 1:21 a.m. |
| From Russia with Love | 100 | March 18, 2016, 7:48 p.m. |
| Snow White and the seven dwarfs | 100 | March 18, 2016, 6:52 p.m. |
| Number Sequence — Part 6 | 100 | March 18, 2016, 5:47 p.m. |
| M-138 — Part 2 | 1,148 | March 16, 2016, 4:48 p.m. |
| M-138 — Part 1 | 100 | March 15, 2016, 2:22 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,098 | March 9, 2016, 3:44 p.m. |
| Enigma Combinatorics | 100 | March 7, 2016, 3:39 p.m. |
| Unconcealed RSA messages | 1,104 | Feb. 25, 2016, 3:15 p.m. |
| CMEA 1 | 1,099 | Feb. 24, 2016, 3:44 p.m. |
| ¿No Hablas Español? No problemo! | 100 | Jan. 21, 2016, 6:22 p.m. |
| Hybrid Encryption I | 1,099 | Jan. 21, 2016, 6:10 p.m. |
| Ku Klux Klan | 1,000 | Jan. 12, 2016, 9:24 p.m. |
| A really long number sequence | 1,104 | Jan. 5, 2016, 10:54 p.m. |
| A hidden word — Part 2 | 100 | Jan. 5, 2016, 6:31 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Jan. 4, 2016, 4:07 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Jan. 4, 2016, 3:22 p.m. |
| A hidden word | 100 | Jan. 3, 2016, 10:27 p.m. |
| An Invisible Message | 100 | Dec. 31, 2015, 4:41 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,107 | Dec. 23, 2015, 2:26 p.m. |
| Smartcard RSA | 1,099 | Dec. 23, 2015, noon |
| RSA: Two different keys — same ciphertext | 1,104 | Dec. 22, 2015, 3:26 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,099 | Dec. 22, 2015, 1:28 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,104 | Dec. 22, 2015, 11:56 a.m. |
| Alice's Birthday Party (Part 2) | 1,099 | Dec. 22, 2015, 2:54 a.m. |
| Alice's Birthday Party (Part 1) | 1,099 | Dec. 22, 2015, 1:13 a.m. |
| Recycled One-Time Pad | 100 | Dec. 21, 2015, 3:36 p.m. |
| Monoalphabetic Substitution | 100 | Dec. 21, 2015, 3:05 p.m. |
| How do you become a big cryptographer? | 100 | Dec. 21, 2015, 2:44 p.m. |
| Grille Cipher | 100 | Dec. 21, 2015, 7:20 a.m. |
| Cracking SHA1-Hashed Passwords | 1,102 | Dec. 20, 2015, 7:50 p.m. |
| Factorization Cipher — Part 2 | 1,106 | Dec. 20, 2015, 6:50 p.m. |
| Factorization Cipher — Part 1 | 100 | Dec. 20, 2015, 4:48 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Dec. 20, 2015, 3:11 p.m. |
| Number Sequence — Part 4 | 100 | Dec. 19, 2015, 8:42 p.m. |
| Letter to the Templars — Part 3 | 1,113 | Dec. 19, 2015, 3:15 p.m. |
| Letter to the Templars — Part 2 | 100 | Dec. 19, 2015, 2:54 p.m. |
| Letter to the Templars — Part 1 | 100 | Dec. 19, 2015, 2:19 p.m. |
| Beaver Code | 100 | Dec. 19, 2015, 1:04 p.m. |
| Original Caesar Cipher | 100 | Dec. 17, 2015, 5:09 p.m. |
| One-Time Pad with Flaws | 100 | Dec. 16, 2015, 11:09 a.m. |
| Trifid Cipher | 100 | Dec. 16, 2015, 10:04 a.m. |
| Number Sequence — Part 8 | 101 | Dec. 15, 2015, 5:53 p.m. |
| Image Noise | 104 | Dec. 15, 2015, 5:42 p.m. |
| Number Sequence — Part 3 | 100 | Dec. 9, 2015, 4:03 p.m. |
| Caesar Encryption | 100 | Dec. 9, 2015, 12:47 p.m. |
| Number Sequence — Part 2 | 100 | Dec. 9, 2015, 12:46 p.m. |
| Number Sequence | 100 | Dec. 9, 2015, 12:44 p.m. |
Gold6
Silver7
Bronze11
