| Merkle-Hellman Knapsack Challenge - Part 1 | 100 | June 19, 2023, 4:39 p.m. |
| Merkle-Hellman Knapsack Challenge — Part 2 | 1,176 | June 19, 2023, 4:38 p.m. |
| The Syllabary Cipher – Part 1 | 101 | April 18, 2023, 10:42 a.m. |
| The Syllabary Cipher – Part 2 | 1,196 | April 18, 2023, 10:42 a.m. |
| The Syllabary Cipher – Part 3 | 1,196 | April 18, 2023, 10:41 a.m. |
| The Syllabary Cipher – Part 4 | 1,196 | April 18, 2023, 10:40 a.m. |
| The Syllabary Cipher – Part 5 | 1,196 | April 18, 2023, 10:39 a.m. |
| Alberti Challenge — Part 2 | 1,414 | May 29, 2022, 2:38 p.m. |
| Alberti Challenge — Part 1 | 200 | March 27, 2022, 2:19 p.m. |
| The SZ42 Challenge — Part 13 | 2,000 | Oct. 7, 2021, 8:44 a.m. |
| The SZ42 Challenge — Part 12 | 2,000 | Oct. 7, 2021, 7:12 a.m. |
| Kaskade-S/T — Part 3 | 1,082 | Aug. 23, 2021, 2:38 p.m. |
| M-138 — Part 4 | 1,092 | Aug. 21, 2021, 4:42 p.m. |
| ElsieFour — Part 1 | 13,512 | July 20, 2021, 12:27 p.m. |
| Weakened ElsieFour — Part 3 | 1,108 | July 18, 2021, 2:28 p.m. |
| Wheatstone Cryptograph — Part 2 | 2,000 | May 21, 2021, 7:56 p.m. |
| Weakened ElsieFour — Part 1 | 1,115 | May 10, 2021, 7:34 p.m. |
| Wheatstone Cryptograph — Part 1 | 200 | April 22, 2021, 12:34 p.m. |
| The SZ42 Challenge — Part 11 | 1,269 | April 1, 2021, 8:15 a.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 2 | 1,083 | April 1, 2021, 8:09 a.m. |
| The SZ42 Challenge — Part 10 | 2,000 | Jan. 30, 2021, 5:18 p.m. |
| Monoalphabetic Substitution with Camouflage — Part 5 | 1,086 | Jan. 23, 2021, 1:01 p.m. |
| Find the right route — Part 3 | 200 | Dec. 27, 2020, 1:56 p.m. |
| Find the right route — Part 2 | 200 | Dec. 20, 2020, 12:44 p.m. |
| The SZ42 Challenge — Part 9 | 2,000 | Dec. 20, 2020, 11:05 a.m. |
| The SZ42 Challenge — Part 8 | 2,000 | Oct. 31, 2020, 8:54 p.m. |
| Find the right route — Part 1 | 200 | Oct. 28, 2020, 9:35 a.m. |
| The SZ42 Challenge — Part 7 | 2,000 | Oct. 28, 2020, 6:31 a.m. |
| The SZ42 Challenge — Part 6 | 2,000 | Oct. 3, 2020, 2:07 p.m. |
| Sigaba Part 2 | 13,091 | Sept. 15, 2020, 6:36 p.m. |
| The SIGABA Challenge — Part 2 | 1,190 | Sept. 10, 2020, 10:24 p.m. |
| The SIGABA Challenge — Part 1 | 1,190 | Sept. 6, 2020, 6:11 p.m. |
| The SZ42 Challenge — Part 5 | 2,000 | Sept. 3, 2020, 8:26 p.m. |
| Sigaba Part 1 | 1,083 | Sept. 2, 2020, 9:39 p.m. |
| The SZ42 Challenge — Part 4 | 2,000 | Aug. 30, 2020, 12:42 p.m. |
| Purple 1 | 1,083 | Aug. 23, 2020, 3:44 p.m. |
| CMEA 2 | 13,100 | Aug. 22, 2020, 8:23 a.m. |
| The SZ42 Challenge — Part 3 | 2,000 | Aug. 16, 2020, 12:35 p.m. |
| Lattice Part 1 | 1,084 | Aug. 6, 2020, 1:54 p.m. |
| The SZ42 Challenge — Part 2 | 2,000 | Aug. 5, 2020, 9:28 p.m. |
| Typex — Part 2 | 1,090 | July 29, 2020, 4:01 p.m. |
| Typex — Part 1 | 1,090 | July 27, 2020, 5:05 p.m. |
| The SZ42 Challenge — Part 1 | 2,000 | July 23, 2020, 4:28 p.m. |
| Lightweight Introduction to Lattices — Part 3 | 2,000 | July 16, 2020, 10:58 p.m. |
| Akelarre Part 1 | 1,084 | July 8, 2020, 1:45 p.m. |
| Lightweight Introduction to Lattices — Part 2 | 200 | June 24, 2020, 11:44 a.m. |
| Double Column Transposition — Part 2 | 1,095 | May 27, 2020, 2:57 p.m. |
| Spanish Strip Cipher — Part 1 | 1,094 | May 24, 2020, 4:11 p.m. |
| Double Column Transposition — Part 1 | 1,095 | May 22, 2020, noon |
| Lightweight Introduction to Lattices — Part 1 | 200 | May 17, 2020, 12:10 p.m. |
| Double Column Transposition — Part 3 | 1,095 | May 11, 2020, 3:53 p.m. |
| Double Column Transposition — Part 4 | 1,095 | May 8, 2020, 9:06 p.m. |
| ASAC — A Strong(er) ADFGVX Cipher — Part 1 | 1,108 | April 25, 2020, 4:41 p.m. |
| Cascading Encryption — Part 3/3 | 1,091 | April 24, 2020, 6:32 p.m. |
| Cascading Encryption — Part 2/3 | 1,091 | April 23, 2020, 2:25 p.m. |
| Spanish Strip Cipher — Part 2 | 1,095 | April 8, 2020, 1 p.m. |
| Zodiac Cipher | 100 | April 7, 2020, 5:10 p.m. |
| Homophonic Encryption — Part 4 | 1,161 | April 7, 2020, 2:18 p.m. |
| Polyhomophonic Substitution — Part 2 | 2,000 | March 29, 2020, 2:49 p.m. |
| Polyhomophonic Substitution — Part 1 | 200 | March 22, 2020, 10:06 a.m. |
| Monoalphabetic Substitution with Nostradamus Flavor | 1,155 | March 6, 2020, 1:47 p.m. |
| Enigma Part 1 | 1,084 | Feb. 28, 2020, 1:35 p.m. |
| RSA with Special d | 13,115 | Feb. 22, 2020, 11:24 a.m. |
| The LoRa Cipher: Logic Randomness — Part 1 | 2,000 | Feb. 20, 2020, 8:26 a.m. |
| Differential Cryptanalysis — Part 2 | 2,000 | Jan. 29, 2020, 5:52 a.m. |
| A really long number sequence | 1,087 | Jan. 21, 2020, 2:16 p.m. |
| Polyphonic Substitution Cipher — Part 2 | 2,000 | Jan. 15, 2020, 11:18 a.m. |
| Christmas Challenge 2019: Differential Cryptanalysis — Part 1 | 1,660 | Dec. 26, 2019, 4:31 p.m. |
| Smartcard RSA | 1,085 | Dec. 14, 2019, 6:51 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,088 | Dec. 12, 2019, 10:58 a.m. |
| Pigpen with a twist — Part 2 | 1,087 | Dec. 8, 2019, 4:27 p.m. |
| Polyphonic Substitution Cipher — Part 1 | 1,423 | Dec. 5, 2019, 5:45 p.m. |
| Pigpen with a twist — Part 3 | 1,087 | Nov. 26, 2019, 1:44 p.m. |
| Cipher ID — Part 1 | 1,725 | Nov. 21, 2019, 5:34 p.m. |
| Holographic Encryption — Part 2 | 1,120 | Nov. 16, 2019, 1:49 p.m. |
| Holographic Encryption — Part 1 | 1,120 | Nov. 8, 2019, 6:32 p.m. |
| "The Road" — Part 1 | 1,163 | Oct. 30, 2019, 12:18 p.m. |
| Not-so-Secret Message from Malawi — Part II (ECC) | 1,085 | Oct. 27, 2019, 11:04 a.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | Oct. 21, 2019, 1:41 p.m. |
| Music Code — Part 2 | 1,087 | Oct. 20, 2019, 1:11 p.m. |
| Music Code — Part 1 | 100 | Oct. 20, 2019, 1:09 p.m. |
| An 'unhearable' message | 100 | Oct. 18, 2019, 12:14 p.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,086 | Oct. 12, 2019, 5:13 p.m. |
| Heartbleed — Part 2 | 100 | Oct. 6, 2019, 4:45 p.m. |
| Heartbleed — Part 1 | 100 | Oct. 6, 2019, 3:24 p.m. |
| Molehunt (Part 3/3) | 1,085 | Oct. 6, 2019, 12:35 p.m. |
| Turing Bombe Enigma I | 100 | Oct. 5, 2019, 12:51 p.m. |
| Enigma Combinatorics | 100 | Oct. 5, 2019, 11:31 a.m. |
| Weakened Granit — Part 1 | 100 | Oct. 3, 2019, 2:26 p.m. |
| Number Sequence — Part 9 | 100 | Oct. 3, 2019, 10:46 a.m. |
| Number Sequence — Part 6 | 100 | Oct. 2, 2019, 2:59 p.m. |
| The Book Code: A Challenge for Bookworms | 100 | Oct. 2, 2019, 1:38 p.m. |
| Keyshanc — Part 2 | 1,090 | Oct. 1, 2019, 11:21 a.m. |
| Keyshanc — Part 1 | 1,090 | Sept. 30, 2019, 3:02 p.m. |
| Playfair with hints about the grid | 100 | Sept. 30, 2019, 12:54 p.m. |
| Modular Sequences | 100 | Sept. 30, 2019, 11:53 a.m. |
| Number Sequence — Part 10 | 100 | Sept. 29, 2019, 4:37 p.m. |
| Playfair Encryption | 100 | Sept. 29, 2019, 1:06 p.m. |
| Flawed Usage of a OTP Cipher by the BND | 1,106 | Sept. 28, 2019, 5:08 p.m. |
| ECDH-Key Exchange for Beginners | 100 | Sept. 27, 2019, 9:58 a.m. |
| Double Columnar Transposition | 100 | Sept. 26, 2019, 3:45 p.m. |
| A hidden word — Part 2 | 100 | Sept. 26, 2019, 12:10 p.m. |
| Recycled One-Time Pad | 100 | Sept. 26, 2019, 10:51 a.m. |
| Strange Message from Thessaloniki | 100 | Sept. 24, 2019, 5:43 p.m. |
| Multilingual Monoalphabetic Substitution | 100 | Sept. 23, 2019, 4:11 p.m. |
| Autokey Cipher | 100 | Sept. 22, 2019, 4:24 p.m. |
| News from Castle Mansfeld | 100 | Sept. 22, 2019, 3:39 p.m. |
| A Secret Message from Castle Mansfeld | 100 | Sept. 22, 2019, 1:36 p.m. |
| An Invisible Message | 100 | Sept. 21, 2019, 4:21 p.m. |
| The Last Note | 100 | Sept. 21, 2019, 11:13 a.m. |
| Molehunt (Part 2/3) | 100 | Sept. 19, 2019, 4:22 p.m. |
| Molehunt (Part 1/3) | 100 | Sept. 19, 2019, 3:04 p.m. |
| Image Noise | 100 | Sept. 18, 2019, 2:15 p.m. |
| Enigma Messages | 100 | Sept. 17, 2019, 3:17 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | Sept. 17, 2019, 2:29 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | Sept. 17, 2019, 11:55 a.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | Sept. 17, 2019, 11:19 a.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | Sept. 17, 2019, 9:44 a.m. |
| ¿No Hablas Español? No problemo! | 100 | Sept. 16, 2019, 4:29 p.m. |
| Nils away on travel | 100 | Sept. 16, 2019, 1:10 p.m. |
| Trifid Cipher | 100 | Sept. 15, 2019, 3:51 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | Sept. 15, 2019, 8:11 a.m. |
| Modified Caesar Cipher | 100 | Sept. 14, 2019, 4:26 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Sept. 14, 2019, 12:21 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | Sept. 13, 2019, 3:52 p.m. |
| One-Time Pad with Flaws | 100 | Sept. 13, 2019, 2:10 p.m. |
| From Russia with Love | 100 | Sept. 13, 2019, 12:07 p.m. |
| How do you become a big cryptographer? | 100 | Sept. 12, 2019, 2:21 p.m. |
| Snow White and the seven dwarfs | 100 | Sept. 12, 2019, 10:18 a.m. |
| Grille Cipher | 100 | Sept. 12, 2019, 9:26 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Sept. 12, 2019, 9:23 a.m. |
| A hidden word | 100 | Sept. 11, 2019, 2:10 p.m. |
| Beaver Code | 100 | Sept. 11, 2019, 2:08 p.m. |
| Caesar Encryption | 100 | Sept. 11, 2019, 12:13 p.m. |
| Original Caesar Cipher | 100 | Sept. 11, 2019, 11:26 a.m. |
| Kaskade-S/T — Part 2 | 1,086 | Sept. 10, 2019, 12:25 p.m. |
| Kaskade-S/T — Part 1 | 100 | Sept. 7, 2019, 1:05 p.m. |
| Hilly — Part 1 | 1,120 | Sept. 4, 2019, 2:38 p.m. |
| Breaking a Filter Generator | 1,161 | Aug. 30, 2019, 12:17 p.m. |
| A Cloaked Substitution Cipher — Part 2 | 2,000 | Aug. 26, 2019, 12:30 p.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,089 | Aug. 22, 2019, 3:11 p.m. |
| A Cloaked Substitution Cipher — Part 1 | 1,824 | Aug. 22, 2019, 12:59 p.m. |
| BCR code (Book-Caesar-RSA) | 1,091 | Aug. 18, 2019, 11:52 a.m. |
| ORYX Stream Cipher — Part 3 (revised) | 1,094 | Aug. 7, 2019, 12:50 p.m. |
| ORYX Stream Cipher Part II | 1,086 | Aug. 5, 2019, 4 p.m. |
| ORYX Stream Cipher Part I | 1,086 | Aug. 4, 2019, 3:58 p.m. |
| Fastest in the West | 1,152 | Aug. 1, 2019, 2:43 p.m. |
| CMEA 1 | 1,086 | July 19, 2019, 3:23 p.m. |
| M-138 — Part 3 | 1,103 | July 14, 2019, 2:56 p.m. |
| Pigpen with a twist — Part 1 | 100 | July 12, 2019, 1:54 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,086 | July 11, 2019, 2:23 p.m. |
| Hybrid Encryption I | 1,086 | July 10, 2019, 11:45 a.m. |
| M-138 — Part 2 | 1,103 | July 9, 2019, 2:14 p.m. |
| M-138 — Part 1 | 100 | July 8, 2019, 4:18 p.m. |
| Cracking SHA1-Hashed Passwords | 1,087 | July 8, 2019, 1:47 p.m. |
| Letter to the Templars — Part 3 | 1,092 | July 7, 2019, 4:39 p.m. |
| Letter to the Templars — Part 2 | 100 | July 7, 2019, 4:38 p.m. |
| Letter to the Templars — Part 1 | 100 | July 7, 2019, 4:35 p.m. |
| Enigma Part 2 | 1,086 | July 5, 2019, 1:36 p.m. |
| Monoalphabetic Substitution | 100 | July 2, 2019, 1 p.m. |
| New Year's Greetings — Part 2 | 100 | June 30, 2019, 12:31 p.m. |
| New Year's Greetings — Part 1 | 100 | June 30, 2019, 11:47 a.m. |
| ADFGVX — Part 2 | 100 | June 29, 2019, 4:55 p.m. |
| ADFGVX — Part 1 | 100 | June 29, 2019, 3:13 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | June 24, 2019, 10:48 a.m. |
| The Einstein Enigma | 1,144 | June 22, 2019, 3:29 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,086 | June 21, 2019, 2:02 p.m. |
| Alice's Birthday Party (Part 2) | 1,086 | June 20, 2019, 4:22 p.m. |
| Alice's Birthday Party (Part 1) | 1,086 | June 20, 2019, 3:57 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 101 | June 12, 2019, 1:31 p.m. |
| Cryptanalysis Hacking Puzzles — Part 1 | 100 | June 12, 2019, 11:03 a.m. |
| Cascading Encryption — Part 1/3 | 100 | June 7, 2019, 4:19 p.m. |
| Unusual encryption using a diophantine equation | 1,089 | June 1, 2019, 2:17 p.m. |
| Unconcealed RSA messages | 1,089 | May 27, 2019, 3:10 p.m. |
| Handycipher made in love — Part 1 | 1,233 | May 23, 2019, 2:09 p.m. |
| Handycipher made in love — Part 2 | 1,824 | May 23, 2019, 1:37 p.m. |
| Homophonic Encryption — Part 3 | 1,469 | May 19, 2019, 7:57 a.m. |
| Homophonic Encryption — Part 2 | 1,523 | May 16, 2019, 1:32 p.m. |
| Homophonic Encryption — Part 1 | 1,469 | May 15, 2019, 2:53 p.m. |
| Trendy Messenger | 1,161 | May 13, 2019, 11:02 a.m. |
| Summer Job | 1,161 | May 12, 2019, 1:21 p.m. |
| AES ECB Wrong Encoding | 1,143 | May 12, 2019, 6:23 a.m. |
| RSA: Two different keys — same ciphertext | 1,089 | May 10, 2019, 11:20 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | May 8, 2019, 4:35 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | May 8, 2019, 2:55 p.m. |
| Hill Cipher with Sudoku Key | 100 | May 8, 2019, 12:50 p.m. |
| Factorization Cipher — Part 3 | 1,090 | May 7, 2019, 3:56 p.m. |
| Factorization Cipher — Part 2 | 1,090 | May 5, 2019, 2:19 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,089 | May 3, 2019, 3:02 p.m. |
| Classical Ciphers^3 | 100 | May 2, 2019, 12:56 p.m. |
| Factorization Cipher — Part 1 | 100 | April 24, 2019, 2:20 p.m. |
| Number Sequence — Part 8 | 100 | April 24, 2019, 2:17 p.m. |
| Advent Challenge — Part 4 | 1,145 | April 21, 2019, 12:39 p.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,090 | April 20, 2019, 9:14 p.m. |
| Advent Challenge — Part 3 | 1,145 | April 20, 2019, 9:09 p.m. |
| Advent-Challenge — Part 2 | 1,144 | April 20, 2019, 9:06 p.m. |
| Number Sequence — Part 4 | 100 | April 20, 2019, 8:51 p.m. |
| Advent-Challenge — Part 1 | 100 | April 12, 2019, 3:07 p.m. |
| Number Sequence — Part 3 | 100 | April 12, 2019, 9:11 a.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,090 | April 8, 2019, 12:52 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | April 7, 2019, 4:41 p.m. |
| Number Sequence — Part 2 | 100 | April 4, 2019, 1:21 p.m. |
| Number Sequence | 100 | April 4, 2019, 1:15 p.m. |
Gold8
Silver7
Bronze6
