| The Hutton Cipher – Part 2 | 2,000 | June 5, 2023, 9:03 p.m. |
| The Heavy T52 Sturgeon Challenge — Part 6 | 13,613 | May 22, 2023, 2:58 p.m. |
| The Heavy T52 Sturgeon Challenge — Part 7 | 13,619 | May 10, 2023, 1:15 a.m. |
| The Hutton Cipher – Part 1 | 1,824 | May 4, 2023, 11:08 a.m. |
| The Josse Challenge – Part 3 | 2,000 | March 27, 2023, 11:46 a.m. |
| The Josse Challenge – Part 2 | 2,000 | Feb. 25, 2023, 11:08 a.m. |
| The Josse Challenge – Part 1 | 2,000 | Feb. 11, 2023, 12:20 a.m. |
| The Syllabary Cipher – Part 1 | 200 | Oct. 28, 2022, 2:25 p.m. |
| Merkle-Hellman Knapsack Challenge — Part 2 | 1,547 | Oct. 21, 2022, 2:51 p.m. |
| Merkle-Hellman Knapsack Challenge - Part 1 | 200 | Oct. 15, 2022, 2:20 a.m. |
| Hill Cipher | 1,456 | Sept. 16, 2022, 12:15 a.m. |
| Alberti Challenge — Part 1 | 200 | March 26, 2022, 11:45 p.m. |
| The SZ42 Challenge — Part 13 | 1,824 | Oct. 7, 2021, 11:44 p.m. |
| The SZ42 Challenge — Part 12 | 1,824 | Oct. 7, 2021, 10:19 p.m. |
| Hilly — Part 1 | 1,104 | June 5, 2021, 12:12 p.m. |
| Wheatstone Cryptograph — Part 2 | 2,000 | May 22, 2021, 1:51 a.m. |
| Spanish Strip Cipher — Part 2 | 1,091 | May 20, 2021, 9:05 a.m. |
| Wheatstone Cryptograph — Part 1 | 200 | April 22, 2021, 2:19 a.m. |
| The SZ42 Challenge — Part 11 | 1,307 | March 11, 2021, 11:39 a.m. |
| The SZ42 Challenge — Part 10 | 2,000 | Jan. 30, 2021, 5:40 p.m. |
| Find the right route — Part 3 | 200 | Dec. 27, 2020, 5:23 p.m. |
| The SZ42 Challenge — Part 9 | 2,000 | Dec. 19, 2020, 6:28 p.m. |
| The SZ42 Challenge — Part 8 | 2,000 | Oct. 31, 2020, 9:34 p.m. |
| Find the right route — Part 1 | 200 | Oct. 27, 2020, 8:13 p.m. |
| The SZ42 Challenge — Part 7 | 2,000 | Oct. 27, 2020, 7:33 p.m. |
| The SZ42 Challenge — Part 6 | 2,000 | Oct. 2, 2020, 9:03 p.m. |
| The SZ42 Challenge — Part 5 | 2,000 | Sept. 4, 2020, 11:33 a.m. |
| The SZ42 Challenge — Part 4 | 2,000 | Aug. 30, 2020, 12:14 a.m. |
| The SZ42 Challenge — Part 3 | 2,000 | Aug. 15, 2020, 11:28 p.m. |
| The SZ42 Challenge — Part 2 | 2,000 | Aug. 5, 2020, 11:56 p.m. |
| The SZ42 Challenge — Part 1 | 1,523 | July 30, 2020, 5:36 p.m. |
| Lightweight Introduction to Lattices — Part 3 | 2,000 | July 16, 2020, 2:34 p.m. |
| Lightweight Introduction to Lattices — Part 2 | 200 | June 24, 2020, 1:42 a.m. |
| Lightweight Introduction to Lattices — Part 1 | 108 | May 28, 2020, 1:59 p.m. |
| Lattice Part 1 | 1,085 | May 25, 2020, 10:57 p.m. |
| The Heavy T52 Sturgeon Challenge — Part 5 | 18,745 | April 23, 2020, 11:55 p.m. |
| The Heavy T52 Sturgeon Challenge — Part 4 | 17,893 | April 20, 2020, 9:51 p.m. |
| Polyhomophonic Substitution — Part 3 | 2,000 | April 7, 2020, 3:25 p.m. |
| Polyhomophonic Substitution — Part 2 | 2,000 | March 28, 2020, 10:26 p.m. |
| Polyhomophonic Substitution — Part 1 | 200 | March 22, 2020, 4:33 p.m. |
| The SIGABA Challenge — Part 3 | 18,390 | March 15, 2020, 7:50 a.m. |
| The SIGABA Challenge — Part 2 | 1,576 | March 11, 2020, 11:19 a.m. |
| The SIGABA Challenge — Part 1 | 1,523 | March 8, 2020, 5:38 a.m. |
| The LoRa Cipher: Logic Randomness — Part 1 | 2,000 | Feb. 20, 2020, 2:32 a.m. |
| Holographic Encryption — Part 1 | 1,117 | Feb. 3, 2020, 8:16 a.m. |
| Differential Cryptanalysis — Part 2 | 1,824 | Jan. 30, 2020, 12:15 a.m. |
| Spirale — Part 2 | 1,103 | Jan. 28, 2020, 12:25 p.m. |
| Spirale — Part 1 | 1,103 | Jan. 28, 2020, 12:24 p.m. |
| Polyphonic Substitution Cipher — Part 2 | 2,000 | Jan. 14, 2020, 8:46 p.m. |
| Christmas Challenge 2019: Differential Cryptanalysis — Part 1 | 1,523 | Dec. 30, 2019, 3:08 a.m. |
| RSA Factoring Challenge: RSA-240 | 0 | Dec. 3, 2019, 2:09 a.m. |
| Polyphonic Substitution Cipher — Part 1 | 1,547 | Nov. 28, 2019, 2:28 a.m. |
| Cipher ID — Part 1 | 1,613 | Nov. 23, 2019, 10:20 p.m. |
| A Cloaked Substitution Cipher — Part 2 | 2,000 | Aug. 26, 2019, 3:17 p.m. |
| A Cloaked Substitution Cipher — Part 1 | 1,824 | Aug. 23, 2019, 9:06 a.m. |
| The T52 Sturgeon Challenge — Part 9 | 1,456 | Aug. 21, 2019, 10:34 p.m. |
| The T52 Sturgeon Challenge — Part 10 | 1,485 | Aug. 20, 2019, 3:56 a.m. |
| The T52 Sturgeon Challenge — Part 8 | 1,523 | Aug. 18, 2019, 4:55 p.m. |
| The T52 Sturgeon Challenge — Part 12 | 1,523 | Aug. 18, 2019, 3:58 p.m. |
| The T52 Sturgeon Challenge — Part 11 | 1,523 | Aug. 18, 2019, 3:58 p.m. |
| The T52 Sturgeon Challenge — Part 6 | 1,613 | Aug. 15, 2019, 2:53 p.m. |
| The T52 Sturgeon Challenge — Part 7 | 1,613 | Aug. 15, 2019, 3:30 a.m. |
| The T52 Sturgeon Challenge — Part 5 | 1,660 | Aug. 13, 2019, 11:24 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | July 29, 2019, 10:37 p.m. |
| The T52 Sturgeon Challenge — Part 4 | 1,725 | July 25, 2019, 6:49 p.m. |
| The T52 Sturgeon Challenge — Part 3 | 2,000 | July 23, 2019, 7:38 a.m. |
| The T52 Sturgeon Challenge — Part 2 | 2,000 | July 23, 2019, 12:55 a.m. |
| The T52 Sturgeon Challenge — Part 1 | 1,725 | July 16, 2019, 4:47 a.m. |
| Handycipher made in love — Part 2 | 2,000 | May 22, 2019, 4:17 a.m. |
| Homophonic Encryption — Part 3 | 1,660 | May 12, 2019, 9:56 a.m. |
| Homophonic Encryption — Part 2 | 1,725 | May 11, 2019, 8:56 p.m. |
| Homophonic Encryption — Part 1 | 2,000 | May 5, 2019, 1:33 p.m. |
| Monoalphabetic Substitution with Nostradamus Flavor | 2,000 | Feb. 17, 2019, 6:54 a.m. |
| Handycipher made in love — Part 1 | 2,000 | Feb. 17, 2019, 5:12 a.m. |
| Cryptanalysis Hacking Puzzles — Part 1 | 113 | Nov. 3, 2018, 3:32 p.m. |
| Breaking a Filter Generator | 1,824 | Sept. 26, 2018, 9:06 p.m. |
| Autokey Cipher | 200 | Sept. 26, 2018, 2:53 a.m. |
| Modular Sequences | 200 | Sept. 26, 2018, 2:12 a.m. |
| Trendy Messenger | 2,000 | June 13, 2018, 11:25 a.m. |
| Fastest in the West | 2,000 | June 13, 2018, 3:24 a.m. |
| Summer Job | 2,000 | June 12, 2018, 9:37 p.m. |
| Number Sequence — Part 10 | 200 | April 18, 2018, 8:22 p.m. |
| The Einstein Enigma | 2,000 | Feb. 8, 2018, 8:23 p.m. |
| Kaskade-S/T — Part 6 (RansomKaskade Part 1) | 1,186 | Jan. 22, 2018, 6:16 p.m. |
| New Year's Greetings — Part 4 | 100 | Jan. 5, 2018, 1:20 a.m. |
| New Year's Greetings — Part 3 | 100 | Jan. 5, 2018, 1:18 a.m. |
| New Year's Greetings — Part 2 | 100 | Jan. 5, 2018, 1:13 a.m. |
| New Year's Greetings — Part 1 | 100 | Jan. 5, 2018, 1:12 a.m. |
| Kaskade-S/T — Part 3 | 1,092 | Jan. 5, 2018, 1:10 a.m. |
| Advent Challenge — Part 3 | 2,000 | Dec. 22, 2017, 7:43 p.m. |
| Advent Challenge — Part 4 | 2,000 | Dec. 21, 2017, 7:56 p.m. |
| AES ECB Wrong Encoding | 1,824 | Dec. 18, 2017, 1:16 p.m. |
| Advent-Challenge — Part 2 | 2,000 | Dec. 17, 2017, 12:20 a.m. |
| Advent-Challenge — Part 1 | 200 | Dec. 8, 2017, 8:26 p.m. |
| Number Sequence — Part 9 | 200 | Nov. 16, 2017, 11:03 p.m. |
| ASAC — A Strong(er) ADFGVX Cipher — Part 1 | 1,613 | July 13, 2016, 8:55 p.m. |
| Image Noise | 200 | Nov. 21, 2015, 12:31 a.m. |
| News from Castle Mansfeld | 200 | Nov. 13, 2015, 7:34 p.m. |
| Weakened Granit — Part 1 | 200 | Sept. 24, 2015, 4:01 p.m. |
| Number Sequence — Part 8 | 200 | Sept. 14, 2015, 1:23 p.m. |
| Flawed Usage of a OTP Cipher by the BND | 1,576 | Aug. 28, 2015, 10:20 p.m. |
| Weakened Handycipher — Part 3 | 2,000 | May 13, 2015, 9:52 p.m. |
| Weakened Handycipher — Part 2 | 2,000 | May 13, 2015, 4 p.m. |
| Weakened Handycipher — Part 1 | 2,000 | May 13, 2015, 12:44 p.m. |
| A hidden word — Part 2 | 200 | April 16, 2015, 7:50 p.m. |
| Number Sequence — Part 7 | 200 | March 23, 2015, 9:51 p.m. |
| Number Sequence — Part 6 | 200 | March 23, 2015, 6:34 p.m. |
| Ku Klux Klan | 1,000 | Feb. 9, 2015, 7:15 p.m. |
| Concealed Messages — Vigenère's Night Sky | 1,118 | Feb. 8, 2015, 11:55 p.m. |
| Monoalphabetic Substitution with Camouflage — Part 5 | 1,117 | Jan. 14, 2015, 7:29 p.m. |
| M-138 — Part 3 | 1,725 | Dec. 26, 2014, 3:32 a.m. |
| M-138 — Part 4 | 2,000 | Dec. 24, 2014, 12:41 p.m. |
| M-138 — Part 2 | 2,000 | Dec. 24, 2014, 8:23 a.m. |
| M-138 — Part 1 | 200 | Dec. 24, 2014, 6:16 a.m. |
| The Last Note | 150 | Sept. 24, 2014, 1:28 a.m. |
| Heartbleed — Part 3 | 2,000 | Aug. 29, 2014, 11:41 a.m. |
| Heartbleed — Part 2 | 200 | Aug. 29, 2014, 12:21 a.m. |
| Heartbleed — Part 1 | 200 | Aug. 28, 2014, 7:22 p.m. |
| Sigaba Part 1 | 1,109 | May 27, 2014, 12:23 a.m. |
| Double Column Transposition — Part 4 | 2,000 | May 20, 2014, 1:16 a.m. |
| ORYX Stream Cipher — Part 4a | 1,330 | May 15, 2014, 8:49 p.m. |
| Double Column Transposition — Part 2 | 2,000 | May 2, 2014, 9:43 p.m. |
| Double Column Transposition — Part 3 | 2,000 | May 2, 2014, 2:20 p.m. |
| Double Column Transposition — Part 1 | 1,423 | April 19, 2014, 4:35 a.m. |
| Spanish Strip Cipher — Part 1 | 1,824 | March 28, 2014, 9:39 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 200 | March 6, 2014, 12:12 a.m. |
| Enigma Messages with Repeated Letters — Part 4 | 200 | March 6, 2014, midnight |
| Enigma Messages with Repeated Letters — Part 5 | 200 | March 5, 2014, 8:32 p.m. |
| Purple 1 | 1,115 | Nov. 2, 2013, 12:51 p.m. |
| Cascading Encryption — Part 3/3 | 1,183 | Nov. 1, 2013, 9:31 a.m. |
| Enigma Messages with Repeated Letters — Part 2 | 200 | Oct. 29, 2013, 4:44 p.m. |
| Trifid Cipher | 200 | Oct. 29, 2013, 1:01 a.m. |
| Cascading Encryption — Part 2/3 | 1,185 | Oct. 18, 2013, 10:38 p.m. |
| A Secret Message from Castle Mansfeld | 100 | Oct. 16, 2013, 7:31 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 200 | Sept. 26, 2013, 7:48 p.m. |
| Hill Cipher with Sudoku Key | 125 | Sept. 8, 2013, 3:12 p.m. |
| From Russia with Love | 200 | Sept. 4, 2013, 11:29 p.m. |
| Not-so-Secret Message from Malawi — Part II (ECC) | 1,117 | Aug. 17, 2013, 10:40 p.m. |
| Nils away on travel | 200 | Aug. 9, 2013, 10:04 a.m. |
| RSA with Special d | 13,661 | Aug. 1, 2013, 11:14 a.m. |
| ORYX Stream Cipher — Part 3 (revised) | 2,000 | June 7, 2013, 3:14 a.m. |
| Snow White and the seven dwarfs | 200 | April 20, 2013, 1:44 p.m. |
| Typex — Part 2 | 2,000 | April 4, 2013, 2:36 a.m. |
| Reserve Hand Procedure — Part 1 | 200 | March 6, 2013, 11:14 p.m. |
| Typex — Part 1 | 1,725 | March 3, 2013, 1:19 a.m. |
| Multilingual Monoalphabetic Substitution | 125 | Feb. 2, 2013, 8:57 p.m. |
| Cascading Encryption — Part 1/3 | 125 | Jan. 28, 2013, 11:40 p.m. |
| Enigma Messages | 200 | Jan. 24, 2013, 12:33 p.m. |
| Playfair with hints about the grid | 200 | Jan. 16, 2013, 9:05 p.m. |
| A hidden word | 200 | Jan. 6, 2013, 4:45 p.m. |
| Strange Message from Thessaloniki | 200 | Dec. 11, 2012, 5:49 a.m. |
| Unusual encryption using a diophantine equation | 1,147 | Dec. 8, 2012, 6:06 p.m. |
| Recycled One-Time Pad | 114 | Nov. 26, 2012, 7:21 p.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,165 | Nov. 19, 2012, 2:25 p.m. |
| CMEA 2 | 13,846 | Nov. 17, 2012, 3:01 p.m. |
| CMEA 1 | 1,130 | Nov. 15, 2012, 10:14 a.m. |
| Music Code — Part 2 | 1,141 | Nov. 3, 2012, 12:10 p.m. |
| A really long number sequence | 1,151 | Nov. 2, 2012, 10:52 p.m. |
| Music Code — Part 1 | 100 | Oct. 19, 2012, 1:45 a.m. |
| Smartcard RSA | 1,130 | Oct. 10, 2012, 11:05 p.m. |
| Letter to the Templars — Part 3 | 2,000 | Oct. 9, 2012, 4:42 p.m. |
| Zodiac Cipher | 100 | Oct. 7, 2012, 10:47 p.m. |
| Turing Bombe Enigma I | 100 | Oct. 4, 2012, 5:25 p.m. |
| Enigma Combinatorics | 100 | Sept. 25, 2012, midnight |
| BCR code (Book-Caesar-RSA) | 1,456 | Sept. 23, 2012, 9:46 p.m. |
| Beaver Code | 200 | Aug. 13, 2012, 8:37 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Aug. 1, 2012, 12:16 a.m. |
| Letter to the Templars — Part 2 | 200 | July 30, 2012, 8:40 p.m. |
| Letter to the Templars — Part 1 | 200 | July 16, 2012, 10:59 p.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,184 | July 6, 2012, 12:33 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,185 | July 4, 2012, 1:01 a.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 101 | July 1, 2012, 12:45 a.m. |
| Pigpen with a twist — Part 3 | 1,168 | June 21, 2012, 9:38 p.m. |
| Pigpen with a twist — Part 2 | 1,171 | June 3, 2012, 11:37 p.m. |
| Playfair Encryption | 100 | June 1, 2012, 1:34 a.m. |
| Pigpen with a twist — Part 1 | 100 | June 1, 2012, 12:22 a.m. |
| How do you become a big cryptographer? | 200 | May 29, 2012, 1:44 a.m. |
| Keyshanc — Part 2 | 2,000 | May 22, 2012, 7:38 p.m. |
| Keyshanc — Part 1 | 2,000 | May 22, 2012, 2:27 p.m. |
| ECDH-Key Exchange for Beginners | 101 | May 11, 2012, 12:40 a.m. |
| ¿No Hablas Español? No problemo! | 105 | May 8, 2012, 10:25 p.m. |
| ORYX Stream Cipher Part II | 1,139 | April 28, 2012, 12:41 p.m. |
| ORYX Stream Cipher Part I | 1,139 | April 27, 2012, 10:46 p.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,146 | April 25, 2012, 5:17 p.m. |
| Number Sequence — Part 4 | 114 | April 25, 2012, 8:36 a.m. |
| Modified Caesar Cipher | 100 | April 16, 2012, 11:24 p.m. |
| Cracking SHA1-Hashed Passwords | 1,156 | April 14, 2012, 7:16 a.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,140 | April 13, 2012, 9:12 p.m. |
| Number Sequence — Part 3 | 108 | April 11, 2012, 4:34 p.m. |
| Unconcealed RSA messages | 1,200 | April 11, 2012, 12:48 a.m. |
| Enigma Part 2 | 1,140 | April 7, 2012, 5:10 p.m. |
| Enigma Part 1 | 1,141 | April 6, 2012, 5:42 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,279 | April 5, 2012, 1:18 p.m. |
| Hybrid Encryption I | 1,142 | April 4, 2012, 1:17 a.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,141 | April 3, 2012, 5:31 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | April 3, 2012, 12:39 p.m. |
| An Invisible Message | 101 | April 1, 2012, 8:52 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,175 | March 29, 2012, 10:19 a.m. |
| Alice's Birthday Party (Part 1) | 1,141 | March 29, 2012, 1:09 a.m. |
| RSA: Two different keys — same ciphertext | 1,181 | March 28, 2012, 1:14 p.m. |
| Alice's Birthday Party (Part 2) | 1,141 | March 27, 2012, 1:52 a.m. |
| Factorization Cipher — Part 3 | 1,249 | March 24, 2012, 12:59 a.m. |
| Factorization Cipher — Part 2 | 1,222 | March 22, 2012, 9:19 p.m. |
| The Book Code: A Challenge for Bookworms | 200 | March 21, 2012, 6:40 p.m. |
| Classical Ciphers^3 | 100 | March 19, 2012, 1:46 a.m. |
| Molehunt (Part 3/3) | 1,143 | March 18, 2012, 9:23 p.m. |
| Molehunt (Part 2/3) | 100 | March 16, 2012, 10:47 p.m. |
| Molehunt (Part 1/3) | 100 | March 16, 2012, 9:51 p.m. |
| Kaskade-S/T — Part 2 | 1,156 | March 15, 2012, 7:48 p.m. |
| Kaskade-S/T — Part 1 | 100 | March 14, 2012, 1:54 p.m. |
| Double Columnar Transposition | 101 | March 13, 2012, 7:08 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | March 11, 2012, 12:52 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | March 10, 2012, 1:15 a.m. |
| ADFGVX — Part 1 | 100 | March 8, 2012, 5:34 p.m. |
| ADFGVX — Part 2 | 100 | March 7, 2012, 8:54 p.m. |
| One-Time Pad with Flaws | 100 | March 6, 2012, 7:22 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 101 | March 6, 2012, 3:49 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | March 6, 2012, 2:48 p.m. |
| Grille Cipher | 101 | March 6, 2012, 12:50 a.m. |
| Factorization Cipher — Part 1 | 101 | March 5, 2012, 11:08 p.m. |
| Monoalphabetic Substitution | 100 | March 5, 2012, 9:49 p.m. |
| Number Sequence | 100 | March 5, 2012, 9:46 p.m. |
| Caesar Encryption | 100 | March 5, 2012, 9:45 p.m. |
| Original Caesar Cipher | 100 | March 5, 2012, 9:42 p.m. |
| Number Sequence — Part 2 | 100 | March 5, 2012, 9:40 p.m. |
Gold30
Silver36
Bronze22
