| Merkle-Hellman Knapsack Challenge - Part 1 | 100 | July 4, 2023, 7:29 p.m. |
| The SIGABA Challenge — Part 4 | 14,143 | May 10, 2021, 11:47 a.m. |
| Purple 1 | 1,082 | April 23, 2021, 8:27 p.m. |
| Wheatstone Cryptograph — Part 1 | 200 | April 21, 2021, 11:31 p.m. |
| The SIGABA Challenge — Part 3 | 14,164 | April 18, 2021, 10:38 p.m. |
| Sigaba Part 2 | 13,068 | April 18, 2021, 10:32 p.m. |
| The SIGABA Challenge — Part 2 | 1,152 | April 17, 2021, 4:43 p.m. |
| Sigaba Part 1 | 1,082 | April 16, 2021, 6:18 p.m. |
| The SIGABA Challenge — Part 1 | 1,153 | April 6, 2021, 9:39 a.m. |
| Double Column Transposition — Part 3 | 1,092 | March 8, 2021, 11:10 p.m. |
| Breaking a Filter Generator | 1,122 | March 7, 2021, 2:14 p.m. |
| Lightweight Introduction to Lattices — Part 2 | 100 | March 1, 2021, 6:40 p.m. |
| New Year's Greetings — Part 4 | 100 | Feb. 28, 2021, 4:17 p.m. |
| New Year's Greetings — Part 3 | 100 | Feb. 28, 2021, 3:44 p.m. |
| Polyhomophonic Substitution — Part 2 | 1,162 | Feb. 22, 2021, 6:58 p.m. |
| Polyphonic Substitution Cipher — Part 2 | 1,153 | Feb. 21, 2021, 10:39 p.m. |
| Polyphonic Substitution Cipher — Part 1 | 1,147 | Feb. 21, 2021, 1:18 p.m. |
| Pigpen with a twist — Part 3 | 1,084 | Feb. 4, 2021, 11:34 a.m. |
| M-138 — Part 3 | 1,095 | Jan. 23, 2021, 1:47 p.m. |
| Handycipher made in love — Part 2 | 1,136 | Jan. 22, 2021, 6:34 p.m. |
| Handycipher made in love — Part 1 | 1,130 | Jan. 22, 2021, 5:19 p.m. |
| Image Noise | 100 | Jan. 20, 2021, 11:39 p.m. |
| Number Sequence — Part 7 | 100 | Jan. 20, 2021, 4:27 p.m. |
| Find the right route — Part 3 | 107 | Jan. 9, 2021, 1:39 p.m. |
| The LoRa Cipher: Logic Randomness — Part 1 | 1,164 | Dec. 29, 2020, 4:24 p.m. |
| Monoalphabetic Substitution with Nostradamus Flavor | 1,132 | Dec. 28, 2020, 5:35 p.m. |
| Find the right route — Part 2 | 111 | Dec. 27, 2020, 7:25 p.m. |
| Find the right route — Part 1 | 102 | Dec. 27, 2020, 12:57 p.m. |
| Cipher ID — Part 1 | 1,153 | Dec. 27, 2020, 11:28 a.m. |
| Lightweight Introduction to Lattices — Part 3 | 1,725 | July 19, 2020, 11:13 a.m. |
| Polyhomophonic Substitution — Part 1 | 101 | July 4, 2020, 1:03 p.m. |
| Lightweight Introduction to Lattices — Part 1 | 102 | July 2, 2020, 11:25 p.m. |
| A Cloaked Substitution Cipher — Part 2 | 1,252 | Nov. 8, 2019, 1:51 p.m. |
| A Cloaked Substitution Cipher — Part 1 | 1,262 | Oct. 25, 2019, 8:45 p.m. |
| Homophonic Encryption — Part 2 | 1,197 | Oct. 22, 2019, 10:15 p.m. |
| Homophonic Encryption — Part 4 | 1,198 | Oct. 21, 2019, 7:24 p.m. |
| Homophonic Encryption — Part 1 | 1,197 | Oct. 21, 2019, 10:10 a.m. |
| Homophonic Encryption — Part 3 | 1,198 | Oct. 20, 2019, 10:10 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Oct. 19, 2019, 3:54 p.m. |
| Hilly — Part 2 | 1,156 | Oct. 29, 2018, 9:19 p.m. |
| Autokey Cipher | 150 | Sept. 26, 2018, 8:50 p.m. |
| Modular Sequences | 200 | Sept. 25, 2018, 3:30 p.m. |
| Hilly — Part 1 | 1,139 | Aug. 7, 2018, 11:17 a.m. |
| AES ECB Wrong Encoding | 1,180 | Aug. 3, 2018, 11:01 a.m. |
| Advent Challenge — Part 4 | 1,181 | Aug. 2, 2018, 4:48 p.m. |
| Trendy Messenger | 1,288 | July 30, 2018, 4:34 p.m. |
| Fastest in the West | 1,288 | July 30, 2018, 3:10 p.m. |
| Summer Job | 1,294 | July 27, 2018, 3:28 p.m. |
| The Einstein Enigma | 1,197 | July 27, 2018, 2:56 p.m. |
| Number Sequence — Part 10 | 101 | July 26, 2018, 5:18 p.m. |
| Advent Challenge — Part 3 | 1,824 | Dec. 24, 2017, 12:12 p.m. |
| Advent-Challenge — Part 2 | 1,824 | Dec. 18, 2017, 4:55 p.m. |
| Advent-Challenge — Part 1 | 133 | Dec. 11, 2017, 3:18 p.m. |
| Number Sequence — Part 9 | 108 | Nov. 29, 2017, 3:59 p.m. |
| Handycipher — Part 3 | 13,977 | Sept. 13, 2016, 10:59 a.m. |
| ASAC — A Strong(er) ADFGVX Cipher — Part 1 | 1,266 | Sept. 10, 2016, 8:42 a.m. |
| Handycipher — Part 2 | 1,140 | Sept. 6, 2016, 10:35 a.m. |
| Weakened Handycipher — Part 3 | 1,152 | June 24, 2016, 2:59 p.m. |
| Weakened Handycipher — Part 2 | 1,155 | May 31, 2016, 12:37 p.m. |
| Weakened Handycipher — Part 1 | 1,156 | May 18, 2016, 1:14 p.m. |
| Flawed Usage of a OTP Cipher by the BND | 1,172 | May 16, 2016, 9:35 a.m. |
| Spanish Strip Cipher — Part 2 | 1,127 | May 14, 2016, 7:07 p.m. |
| Spanish Strip Cipher — Part 1 | 1,127 | May 13, 2016, 9:57 p.m. |
| Zodiac Cipher | 100 | May 6, 2016, 7:55 p.m. |
| Ku Klux Klan | 1,000 | May 3, 2016, 5:05 p.m. |
| Weakened Granit — Part 1 | 101 | April 9, 2016, 10:31 p.m. |
| News from Castle Mansfeld | 101 | April 8, 2016, 6:38 p.m. |
| Number Sequence — Part 8 | 100 | April 3, 2016, 1:38 p.m. |
| New Year's Greetings — Part 2 | 108 | April 2, 2016, 6:19 p.m. |
| New Year's Greetings — Part 1 | 108 | April 2, 2016, 5:11 p.m. |
| Heartbleed — Part 3 | 1,151 | Oct. 23, 2015, 1:32 p.m. |
| Lattice Part 1 | 1,102 | Oct. 17, 2015, 3:34 p.m. |
| Double Column Transposition — Part 4 | 1,146 | Sept. 6, 2015, 1:03 p.m. |
| Heartbleed — Part 2 | 100 | Sept. 1, 2015, 4:38 p.m. |
| Double Column Transposition — Part 2 | 1,145 | Aug. 31, 2015, 3:27 p.m. |
| The Last Note | 100 | Aug. 31, 2015, 8:29 a.m. |
| A hidden word — Part 2 | 101 | Aug. 27, 2015, 2:31 p.m. |
| Heartbleed — Part 1 | 100 | Aug. 27, 2015, 7:06 a.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,109 | Aug. 22, 2015, 11:48 a.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,109 | Aug. 18, 2015, 6:22 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 2 | 1,104 | July 23, 2015, 10:07 a.m. |
| M-138 — Part 2 | 1,279 | Feb. 15, 2015, 8:06 p.m. |
| M-138 — Part 1 | 102 | Feb. 12, 2015, 3:29 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 101 | Aug. 31, 2014, 3:18 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 200 | March 6, 2014, 12:13 p.m. |
| Keyshanc — Part 2 | 1,133 | March 6, 2014, 12:05 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 200 | March 6, 2014, 11:58 a.m. |
| Pigpen with a twist — Part 2 | 1,121 | March 2, 2014, 6:49 p.m. |
| Trifid Cipher | 101 | Jan. 6, 2014, 3:49 p.m. |
| CMEA 2 | 13,614 | Jan. 1, 2014, midnight |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,116 | Dec. 30, 2013, 6:17 p.m. |
| A really long number sequence | 1,124 | Dec. 30, 2013, 3:30 p.m. |
| CMEA 1 | 1,115 | Dec. 24, 2013, 5:03 p.m. |
| Factorization Cipher — Part 2 | 1,130 | Nov. 18, 2013, 10:09 a.m. |
| RSA with Special d | 13,613 | Nov. 13, 2013, 10:14 a.m. |
| Enigma Messages with Repeated Letters — Part 2 | 200 | Oct. 29, 2013, 11:32 a.m. |
| Smartcard RSA | 1,115 | Oct. 23, 2013, 5:47 p.m. |
| Cascading Encryption — Part 3/3 | 1,186 | Oct. 19, 2013, 5:49 p.m. |
| Enigma Part 2 | 1,115 | Oct. 13, 2013, 11:50 a.m. |
| Enigma Part 1 | 1,115 | Oct. 8, 2013, 9:13 p.m. |
| Playfair Encryption | 100 | Oct. 4, 2013, 6:02 p.m. |
| Kaskade-S/T — Part 3 | 1,120 | Oct. 4, 2013, 5:59 p.m. |
| Music Code — Part 2 | 1,123 | Sept. 28, 2013, 11:59 a.m. |
| Enigma Messages with Repeated Letters — Part 1 | 200 | Sept. 26, 2013, 6:21 p.m. |
| A Secret Message from Castle Mansfeld | 100 | Sept. 26, 2013, 2:06 p.m. |
| Strange Message from Thessaloniki | 100 | Sept. 16, 2013, 3:40 p.m. |
| Cascading Encryption — Part 2/3 | 1,195 | Sept. 14, 2013, 11:30 p.m. |
| Multilingual Monoalphabetic Substitution | 100 | Sept. 10, 2013, 10:07 a.m. |
| Music Code — Part 1 | 100 | Sept. 8, 2013, 11:03 a.m. |
| ¿No Hablas Español? No problemo! | 100 | Sept. 7, 2013, 4:27 p.m. |
| From Russia with Love | 200 | Sept. 4, 2013, 5:42 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Sept. 3, 2013, 7:19 p.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | Aug. 13, 2013, 3:19 p.m. |
| Monoalphabetic Substitution | 100 | Aug. 8, 2013, 2:45 p.m. |
| Nils away on travel | 200 | Aug. 8, 2013, 2:39 p.m. |
| ADFGVX — Part 1 | 100 | Aug. 7, 2013, 2:48 p.m. |
| Cascading Encryption — Part 1/3 | 101 | Aug. 4, 2013, 3:58 p.m. |
| Snow White and the seven dwarfs | 101 | July 29, 2013, 2:59 p.m. |
| Not-so-Secret Message from Malawi — Part II (ECC) | 1,118 | July 17, 2013, 2:15 p.m. |
| Factorization Cipher — Part 3 | 1,139 | July 15, 2013, 5:09 p.m. |
| Unusual encryption using a diophantine equation | 1,132 | July 14, 2013, 11:38 a.m. |
| ORYX Stream Cipher Part II | 1,118 | July 9, 2013, 2:44 p.m. |
| Unconcealed RSA messages | 1,136 | July 8, 2013, 11:19 a.m. |
| ORYX Stream Cipher — Part 3 (revised) | 1,349 | July 3, 2013, 9:44 a.m. |
| How do you become a big cryptographer? | 100 | March 9, 2013, 12:50 p.m. |
| Reserve Hand Procedure — Part 1 | 200 | March 7, 2013, 6:31 p.m. |
| Enigma Messages | 103 | Feb. 23, 2013, 12:29 p.m. |
| ORYX Stream Cipher Part I | 1,123 | Feb. 16, 2013, 9:28 p.m. |
| Playfair with hints about the grid | 150 | Jan. 17, 2013, 11:51 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,125 | Jan. 11, 2013, 11:47 a.m. |
| A hidden word | 150 | Jan. 8, 2013, 11:24 a.m. |
| Molehunt (Part 3/3) | 1,126 | Jan. 3, 2013, 2:25 p.m. |
| Recycled One-Time Pad | 103 | Dec. 23, 2012, 5:38 p.m. |
| Cracking SHA1-Hashed Passwords | 1,136 | Dec. 8, 2012, 5:45 p.m. |
| The Book Code: A Challenge for Bookworms | 100 | Oct. 21, 2012, 1:48 p.m. |
| Turing Bombe Enigma I | 100 | Oct. 20, 2012, 10:16 p.m. |
| Letter to the Templars — Part 3 | 1,660 | Oct. 13, 2012, 10:56 a.m. |
| Molehunt (Part 1/3) | 100 | Sept. 14, 2012, 4:09 p.m. |
| Molehunt (Part 2/3) | 100 | Sept. 14, 2012, 12:41 p.m. |
| BCR code (Book-Caesar-RSA) | 2,000 | Sept. 13, 2012, 11:06 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Sept. 7, 2012, 6:13 p.m. |
| Enigma Combinatorics | 100 | Sept. 4, 2012, 11:12 a.m. |
| Kaskade-S/T — Part 2 | 1,140 | Aug. 30, 2012, 3:41 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,187 | Aug. 30, 2012, 8:43 a.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | Aug. 29, 2012, 12:17 p.m. |
| Kaskade-S/T — Part 1 | 100 | Aug. 25, 2012, 7:40 p.m. |
| Double Columnar Transposition | 100 | Aug. 23, 2012, 11:44 a.m. |
| Beaver Code | 200 | Aug. 14, 2012, 10:19 a.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,185 | Aug. 13, 2012, noon |
| Classical Ciphers^3 | 100 | Aug. 8, 2012, 9:15 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Aug. 7, 2012, 8:47 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Aug. 7, 2012, 1:33 p.m. |
| Number Sequence — Part 3 | 101 | Aug. 7, 2012, 9:30 a.m. |
| Keyshanc — Part 1 | 1,256 | July 31, 2012, 7:41 p.m. |
| Letter to the Templars — Part 2 | 200 | July 31, 2012, 10:10 a.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,133 | July 28, 2012, 10:36 a.m. |
| Hybrid Encryption I | 1,134 | July 26, 2012, 9:15 a.m. |
| ADFGVX — Part 2 | 100 | July 21, 2012, 7:13 p.m. |
| One-Time Pad with Flaws | 100 | July 21, 2012, 11:32 a.m. |
| Broadcasting and low exponent — RSA Attack | 1,157 | July 19, 2012, 11:28 p.m. |
| Pigpen with a twist — Part 1 | 100 | July 18, 2012, 5:05 p.m. |
| Letter to the Templars — Part 1 | 200 | July 17, 2012, noon |
| RSA: Two different keys — same ciphertext | 1,161 | July 16, 2012, 4:57 p.m. |
| Alice's Birthday Party (Part 1) | 1,134 | July 13, 2012, 4:11 p.m. |
| Alice's Birthday Party (Part 2) | 1,134 | July 12, 2012, 10:53 a.m. |
| Grille Cipher | 100 | July 11, 2012, 5:53 p.m. |
| Factorization Cipher — Part 1 | 100 | July 7, 2012, 1:23 p.m. |
| ECDH-Key Exchange for Beginners | 101 | July 6, 2012, 4:40 p.m. |
| Modified Caesar Cipher | 100 | July 6, 2012, 9:08 a.m. |
| Number Sequence — Part 5 | 101 | July 3, 2012, 11:16 p.m. |
| Caesar Encryption | 100 | July 3, 2012, 12:55 p.m. |
| Original Caesar Cipher | 100 | July 2, 2012, 3:57 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | July 2, 2012, 11:31 a.m. |
| Number Sequence — Part 4 | 101 | July 1, 2012, 10:52 p.m. |
| Number Sequence | 100 | June 30, 2012, 4:18 p.m. |
| Number Sequence — Part 2 | 100 | June 30, 2012, 4:05 p.m. |
Gold3
Silver0
Bronze3
