| A disguised code | 105 | Nov. 19, 2023, 3:01 p.m. |
| The Hutton Cipher – Part 2 | 2,000 | June 5, 2023, 6:29 p.m. |
| The Hutton Cipher – Part 1 | 2,000 | May 3, 2023, 3:16 p.m. |
| The Josse Challenge – Part 3 | 1,725 | March 30, 2023, 9:27 a.m. |
| The Josse Challenge – Part 2 | 1,725 | Feb. 27, 2023, 9:39 a.m. |
| The Josse Challenge – Part 1 | 1,406 | Feb. 26, 2023, 2:48 p.m. |
| Breaking a Filter Generator | 1,104 | Feb. 24, 2023, 5:48 p.m. |
| Polyphonic Substitution Cipher — Part 2 | 1,114 | Feb. 12, 2023, 4 p.m. |
| Polyphonic Substitution Cipher — Part 1 | 1,113 | Feb. 10, 2023, 7:47 p.m. |
| The LoRa Cipher: Logic Randomness — Part 1 | 1,116 | Feb. 9, 2023, 1:35 p.m. |
| Monoalphabetic Substitution with Nostradamus Flavor | 1,107 | Feb. 8, 2023, 6:26 p.m. |
| Homophonic Encryption — Part 4 | 1,108 | Feb. 8, 2023, 5:10 p.m. |
| Homophonic Encryption — Part 3 | 1,108 | Feb. 7, 2023, 6:22 p.m. |
| Homophonic Encryption — Part 2 | 1,108 | Feb. 7, 2023, 1:54 p.m. |
| Homophonic Encryption — Part 1 | 1,108 | Feb. 6, 2023, 5:14 p.m. |
| Lightweight Introduction to Lattices — Part 3 | 1,120 | Feb. 6, 2023, 11:25 a.m. |
| Lightweight Introduction to Lattices — Part 2 | 100 | Feb. 5, 2023, 7:02 p.m. |
| Lightweight Introduction to Lattices — Part 1 | 100 | Feb. 5, 2023, 5:29 p.m. |
| Number Sequence — Part 10 | 100 | Feb. 5, 2023, 10:13 a.m. |
| Polyhomophonic Substitution — Part 3 | 1,117 | Jan. 23, 2023, 9:31 a.m. |
| Polyhomophonic Substitution — Part 2 | 1,118 | Jan. 4, 2023, 7:52 p.m. |
| Polyhomophonic Substitution — Part 1 | 100 | Jan. 2, 2023, 11:59 a.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Jan. 1, 2023, 1:57 p.m. |
| Cryptanalysis Hacking Puzzles — Part 1 | 100 | Jan. 1, 2023, 1:43 p.m. |
| Modular Sequences | 100 | Dec. 31, 2022, 7:55 p.m. |
| Find the right route — Part 2 | 100 | Dec. 14, 2022, 3:21 p.m. |
| Find the right route — Part 1 | 100 | Dec. 9, 2022, 4:24 p.m. |
| Wheatstone Cryptograph — Part 2 | 1,140 | Nov. 13, 2022, 6:01 p.m. |
| The Syllabary Cipher – Part 3 | 1,444 | Nov. 9, 2022, 4:19 p.m. |
| Wheatstone Cryptograph — Part 1 | 100 | Nov. 6, 2022, 4:32 p.m. |
| The Syllabary Cipher – Part 2 | 1,523 | Nov. 4, 2022, 3:04 p.m. |
| The Syllabary Cipher – Part 1 | 133 | Oct. 31, 2022, 11:21 a.m. |
| Hill Cipher | 1,273 | Oct. 31, 2022, 9:30 a.m. |
| Alberti Challenge — Part 2 | 1,198 | Oct. 28, 2022, 10:49 a.m. |
| Alberti Challenge — Part 1 | 100 | Oct. 28, 2022, 10:27 a.m. |
| Autokey Cipher | 100 | Oct. 26, 2022, 12:44 p.m. |
| Merkle-Hellman Knapsack Challenge — Part 2 | 1,456 | Oct. 26, 2022, 12:42 p.m. |
| Merkle-Hellman Knapsack Challenge - Part 1 | 108 | Oct. 26, 2022, 12:42 p.m. |
| Trendy Messenger | 1,307 | July 21, 2018, 1:53 p.m. |
| AES ECB Wrong Encoding | 1,184 | July 19, 2018, 9:43 a.m. |
| Hilly — Part 1 | 1,142 | July 3, 2018, 7:30 p.m. |
| Advent Challenge — Part 3 | 1,192 | June 24, 2018, 11:40 p.m. |
| Advent Challenge — Part 4 | 1,192 | June 24, 2018, 6:18 p.m. |
| The Einstein Enigma | 1,210 | June 24, 2018, 10:58 a.m. |
| Advent-Challenge — Part 1 | 101 | June 23, 2018, 11:43 a.m. |
| Summer Job | 1,469 | June 23, 2018, 10:16 a.m. |
| Fastest in the West | 1,485 | June 22, 2018, 12:15 a.m. |
| Handycipher — Part 6 | 15,666 | Aug. 16, 2016, 11:27 p.m. |
| Handycipher — Part 5 | 15,684 | Aug. 16, 2016, 3:08 p.m. |
| Handycipher — Part 4 | 15,684 | Aug. 15, 2016, 9:12 p.m. |
| Weakened Handycipher — Part 6 | 1,307 | Aug. 7, 2016, 12:09 p.m. |
| Weakened Handycipher — Part 5 | 1,310 | Aug. 6, 2016, 4:25 p.m. |
| Weakened Handycipher — Part 4 | 1,310 | Aug. 6, 2016, 2:10 p.m. |
| ASAC — A Strong(er) ADFGVX Cipher — Part 1 | 1,576 | July 15, 2016, 9:41 a.m. |
| New Year's Greetings — Part 5 | 1,502 | March 29, 2016, 2:51 p.m. |
| New Year's Greetings — Part 4 | 117 | March 26, 2016, 7:39 p.m. |
| New Year's Greetings — Part 3 | 117 | March 26, 2016, 7:21 p.m. |
| New Year's Greetings — Part 2 | 117 | March 26, 2016, 7 p.m. |
| New Year's Greetings — Part 1 | 117 | March 26, 2016, 6:34 p.m. |
| Number Sequence — Part 6 | 100 | March 13, 2016, 4:08 p.m. |
| Number Sequence — Part 5 | 100 | March 13, 2016, 3 p.m. |
| ORYX Stream Cipher — Part 4a | 1,132 | Feb. 27, 2016, 6:22 p.m. |
| News from Castle Mansfeld | 102 | Jan. 10, 2016, 6:22 p.m. |
| Number Sequence — Part 8 | 101 | Jan. 9, 2016, 5:21 p.m. |
| Image Noise | 102 | Jan. 9, 2016, 5 p.m. |
| Weakened Granit — Part 1 | 125 | Sept. 27, 2015, 9:54 p.m. |
| Kaskade-S/T — Part 5 | 1,104 | Sept. 15, 2015, 9:06 p.m. |
| Flawed Usage of a OTP Cipher by the BND | 1,456 | Sept. 4, 2015, 4:37 p.m. |
| Sigaba Part 2 | 13,397 | Aug. 26, 2015, 3:54 p.m. |
| M-138 — Part 4 | 1,178 | Aug. 17, 2015, 1:42 p.m. |
| An 'unhearable' message | 100 | July 31, 2015, 9:32 p.m. |
| An Invisible Message | 100 | July 31, 2015, 3:44 p.m. |
| A hidden word — Part 2 | 101 | July 31, 2015, 1:57 p.m. |
| Handycipher — Part 3 | 15,093 | June 12, 2015, 7:31 p.m. |
| Handycipher — Part 2 | 1,232 | June 9, 2015, 11:28 p.m. |
| Handycipher — Part 1 | 1,233 | June 8, 2015, 5:49 p.m. |
| Weakened Handycipher — Part 3 | 1,357 | June 7, 2015, 10:32 a.m. |
| Weakened Handycipher — Part 2 | 1,357 | June 6, 2015, 1:54 p.m. |
| Weakened Handycipher — Part 1 | 1,362 | June 5, 2015, 3:01 p.m. |
| M-138 — Part 3 | 1,341 | Jan. 21, 2015, 7:13 p.m. |
| M-138 — Part 2 | 1,344 | Jan. 20, 2015, 6:40 p.m. |
| M-138 — Part 1 | 104 | Jan. 20, 2015, 5:01 p.m. |
| The Last Note | 101 | Dec. 4, 2014, 10:47 p.m. |
| Akelarre Part 1 | 1,106 | Dec. 3, 2014, 10:26 a.m. |
| Heartbleed — Part 3 | 1,240 | Nov. 23, 2014, 9:20 p.m. |
| Heartbleed — Part 2 | 101 | Nov. 21, 2014, 7:50 p.m. |
| Heartbleed — Part 1 | 101 | Nov. 21, 2014, 10:14 a.m. |
| Cascading Encryption — Part 3/3 | 1,136 | Nov. 20, 2014, 3:44 p.m. |
| Cascading Encryption — Part 2/3 | 1,137 | Nov. 11, 2014, 11:43 a.m. |
| Double Column Transposition — Part 5 | 1,330 | July 25, 2014, 2:02 p.m. |
| Double Column Transposition — Part 4 | 1,398 | June 6, 2014, 10:01 a.m. |
| Double Column Transposition — Part 2 | 2,000 | May 3, 2014, 11:10 a.m. |
| Double Column Transposition — Part 3 | 2,000 | May 3, 2014, 10:17 a.m. |
| Double Column Transposition — Part 1 | 1,433 | April 17, 2014, 11:21 p.m. |
| Spanish Strip Cipher — Part 2 | 2,000 | March 28, 2014, 1:32 a.m. |
| Spanish Strip Cipher — Part 1 | 2,000 | March 27, 2014, 10:27 p.m. |
| Purple 1 | 1,111 | March 15, 2014, 12:32 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 113 | March 12, 2014, 5:33 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 113 | March 12, 2014, 5:27 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 114 | March 12, 2014, 12:08 p.m. |
| Concealed Messages — Vigenère's Night Sky | 1,132 | March 5, 2014, 8:52 a.m. |
| Sigaba Part 1 | 1,112 | Feb. 27, 2014, 10 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 2 | 1,117 | Feb. 26, 2014, 11:08 p.m. |
| Lattice Part 1 | 1,116 | Feb. 14, 2014, 3:03 p.m. |
| Unconcealed RSA messages | 1,124 | Feb. 12, 2014, 8:05 a.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,114 | Feb. 10, 2014, 10:07 a.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,128 | Feb. 9, 2014, 10:56 a.m. |
| BCR code (Book-Caesar-RSA) | 1,143 | Feb. 8, 2014, 5:46 p.m. |
| Smartcard RSA | 1,112 | Feb. 8, 2014, 3:01 p.m. |
| RSA with Special d | 13,577 | Feb. 6, 2014, 4:33 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,130 | Feb. 1, 2014, 5:22 p.m. |
| Pigpen with a twist — Part 3 | 1,123 | Jan. 20, 2014, 7:13 p.m. |
| Pigpen with a twist — Part 2 | 1,123 | Jan. 20, 2014, 6:29 p.m. |
| ORYX Stream Cipher — Part 3 (revised) | 1,180 | Jan. 20, 2014, 5:25 p.m. |
| ORYX Stream Cipher Part II | 1,113 | Jan. 19, 2014, 10:33 a.m. |
| ORYX Stream Cipher Part I | 1,113 | Jan. 18, 2014, 7:10 p.m. |
| Unusual encryption using a diophantine equation | 1,123 | Jan. 14, 2014, 4:59 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 101 | Jan. 14, 2014, 8:22 a.m. |
| Enigma Messages with Repeated Letters — Part 1 | 101 | Jan. 13, 2014, 3:12 p.m. |
| Enigma Part 2 | 1,113 | Jan. 13, 2014, 3:11 p.m. |
| Trifid Cipher | 101 | Jan. 12, 2014, 5:28 p.m. |
| Typex — Part 2 | 1,169 | Jan. 12, 2014, 10:21 a.m. |
| Typex — Part 1 | 1,164 | Jan. 11, 2014, 6:12 p.m. |
| Not-so-Secret Message from Malawi — Part II (ECC) | 1,113 | Jan. 9, 2014, 5:32 p.m. |
| Strange Message from Thessaloniki | 100 | Jan. 8, 2014, 12:21 p.m. |
| The Book Code: A Challenge for Bookworms | 100 | Jan. 7, 2014, 12:14 p.m. |
| Hybrid Encryption I | 1,113 | Jan. 7, 2014, 11:04 a.m. |
| Factorization Cipher — Part 3 | 1,129 | Jan. 7, 2014, 9:30 a.m. |
| RSA: Two different keys — same ciphertext | 1,123 | Jan. 6, 2014, 7:18 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,122 | Jan. 6, 2014, 5:26 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,113 | Jan. 6, 2014, 3:45 p.m. |
| Cascading Encryption — Part 1/3 | 100 | Jan. 4, 2014, 9:58 p.m. |
| Nils away on travel | 101 | Jan. 4, 2014, 9:04 p.m. |
| Cracking SHA1-Hashed Passwords | 1,118 | Jan. 4, 2014, 8:48 p.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | Jan. 4, 2014, 12:15 p.m. |
| Zodiac Cipher | 100 | Jan. 3, 2014, 12:05 p.m. |
| Monoalphabetic Substitution with Camouflage — Part 5 | 1,133 | Jan. 2, 2014, 11:38 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,128 | Jan. 2, 2014, 7:34 p.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,128 | Jan. 2, 2014, 4:42 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Jan. 2, 2014, 9:48 a.m. |
| Keyshanc — Part 2 | 1,137 | Jan. 1, 2014, 4:43 p.m. |
| Keyshanc — Part 1 | 1,137 | Dec. 31, 2013, 11:03 a.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | Dec. 30, 2013, 10:56 p.m. |
| Kaskade-S/T — Part 3 | 1,117 | Dec. 30, 2013, 12:43 a.m. |
| Kaskade-S/T — Part 2 | 1,117 | Dec. 29, 2013, 6:46 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,113 | Dec. 29, 2013, 4:44 p.m. |
| ADFGVX — Part 2 | 100 | Dec. 28, 2013, 7:47 p.m. |
| ADFGVX — Part 1 | 100 | Dec. 28, 2013, 5:56 p.m. |
| Alice's Birthday Party (Part 2) | 1,113 | Dec. 28, 2013, 4:27 p.m. |
| Kaskade-S/T — Part 1 | 100 | Dec. 28, 2013, 12:14 p.m. |
| ECDH-Key Exchange for Beginners | 100 | Dec. 28, 2013, 9:19 a.m. |
| Alice's Birthday Party (Part 1) | 1,113 | Dec. 27, 2013, 4:47 p.m. |
| Factorization Cipher — Part 2 | 1,128 | Dec. 27, 2013, 8:20 a.m. |
| CMEA 2 | 13,617 | Dec. 26, 2013, 12:16 p.m. |
| Hill Cipher with Sudoku Key | 101 | Dec. 25, 2013, 10:16 p.m. |
| CMEA 1 | 1,115 | Dec. 24, 2013, 4:29 p.m. |
| Enigma Messages | 100 | Dec. 21, 2013, 2:40 p.m. |
| A Secret Message from Castle Mansfeld | 100 | Dec. 20, 2013, 7:08 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Dec. 20, 2013, 7:05 p.m. |
| Enigma Part 1 | 1,113 | Dec. 20, 2013, 2:51 p.m. |
| Enigma Combinatorics | 100 | Dec. 20, 2013, 2:38 p.m. |
| Turing Bombe Enigma I | 100 | Dec. 19, 2013, 8:03 p.m. |
| How do you become a big cryptographer? | 100 | Dec. 19, 2013, 1:39 p.m. |
| Double Columnar Transposition | 100 | Dec. 19, 2013, 11:40 a.m. |
| Music Code — Part 2 | 1,120 | Dec. 19, 2013, 10:40 a.m. |
| Music Code — Part 1 | 100 | Dec. 19, 2013, 10:37 a.m. |
| Recycled One-Time Pad | 100 | Dec. 18, 2013, 1:12 p.m. |
| Classical Ciphers^3 | 100 | Dec. 18, 2013, 12:13 p.m. |
| Modified Caesar Cipher | 100 | Dec. 17, 2013, 9:54 a.m. |
| Pigpen with a twist — Part 1 | 100 | Dec. 16, 2013, 7:35 p.m. |
| Molehunt (Part 3/3) | 1,114 | Dec. 16, 2013, 5:33 p.m. |
| Molehunt (Part 2/3) | 100 | Dec. 16, 2013, 1:28 p.m. |
| Molehunt (Part 1/3) | 100 | Dec. 16, 2013, 1:07 p.m. |
| From Russia with Love | 101 | Dec. 16, 2013, 11:42 a.m. |
| A really long number sequence | 1,124 | Dec. 15, 2013, 8:55 p.m. |
| ¿No Hablas Español? No problemo! | 100 | Dec. 15, 2013, 7:57 p.m. |
| Multilingual Monoalphabetic Substitution | 100 | Dec. 15, 2013, 7:39 p.m. |
| Playfair with hints about the grid | 100 | Dec. 15, 2013, 6:28 p.m. |
| Playfair Encryption | 100 | Dec. 15, 2013, 6:07 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | Dec. 15, 2013, 2:34 p.m. |
| Snow White and the seven dwarfs | 100 | Dec. 15, 2013, 12:10 p.m. |
| Letter to the Templars — Part 3 | 1,150 | Dec. 15, 2013, 11:49 a.m. |
| A hidden word | 100 | Dec. 15, 2013, 11:22 a.m. |
| One-Time Pad with Flaws | 100 | Dec. 15, 2013, 10:56 a.m. |
| Grille Cipher | 100 | Dec. 15, 2013, 10:04 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Dec. 15, 2013, 9:51 a.m. |
| Factorization Cipher — Part 1 | 100 | Dec. 15, 2013, 8:47 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Dec. 15, 2013, 8:01 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Dec. 15, 2013, 12:21 a.m. |
| Letter to the Templars — Part 2 | 100 | Dec. 15, 2013, 12:16 a.m. |
| Number Sequence — Part 4 | 100 | Dec. 15, 2013, 12:08 a.m. |
| Letter to the Templars — Part 1 | 100 | Dec. 15, 2013, 12:05 a.m. |
| Number Sequence — Part 3 | 100 | Dec. 14, 2013, 11:38 p.m. |
| Beaver Code | 100 | Dec. 14, 2013, 11:35 p.m. |
| Caesar Encryption | 100 | Dec. 14, 2013, 11:14 p.m. |
| Original Caesar Cipher | 100 | Dec. 14, 2013, 10:34 p.m. |
| Monoalphabetic Substitution | 100 | Dec. 14, 2013, 7:56 p.m. |
| Number Sequence — Part 2 | 100 | Dec. 14, 2013, 6:37 p.m. |
| Number Sequence | 100 | Dec. 14, 2013, 6:34 p.m. |
Gold9
Silver5
Bronze5
