| Alberti Challenge — Part 1 | 100 | Sept. 15, 2023, 8:51 a.m. |
| The Syllabary Cipher – Part 1 | 100 | Sept. 15, 2023, 8:50 a.m. |
| The Syllabary Cipher – Part 2 | 1,163 | Sept. 15, 2023, 8:47 a.m. |
| Find the right route — Part 3 | 100 | Nov. 1, 2021, 8:35 p.m. |
| Wheatstone Cryptograph — Part 1 | 133 | April 23, 2021, 11:07 p.m. |
| The SZ42 Challenge — Part 8 | 1,456 | Nov. 11, 2020, 9:46 p.m. |
| Image Noise | 100 | Nov. 1, 2020, 8:12 p.m. |
| Find the right route — Part 1 | 200 | Oct. 27, 2020, 8:36 p.m. |
| The SZ42 Challenge — Part 5 | 1,824 | Sept. 4, 2020, 6:20 p.m. |
| The SZ42 Challenge — Part 4 | 1,576 | Sept. 4, 2020, 6:19 p.m. |
| M-138 — Part 4 | 1,097 | Aug. 5, 2020, 3:49 p.m. |
| Lightweight Introduction to Lattices — Part 3 | 2,000 | July 16, 2020, 3:07 p.m. |
| Lightweight Introduction to Lattices — Part 2 | 200 | June 24, 2020, 10:36 a.m. |
| Cascading Encryption — Part 2/3 | 1,091 | June 8, 2020, 9:03 a.m. |
| Lightweight Introduction to Lattices — Part 1 | 200 | May 16, 2020, 8:07 p.m. |
| Typex — Part 1 | 1,091 | April 12, 2020, 7:14 p.m. |
| ORYX Stream Cipher Part I | 1,084 | April 10, 2020, 9:04 p.m. |
| Polyhomophonic Substitution — Part 3 | 2,000 | April 7, 2020, 8:54 a.m. |
| Unconcealed RSA messages | 1,087 | April 3, 2020, 4:44 p.m. |
| Lattice Part 1 | 1,085 | April 1, 2020, 2:21 p.m. |
| Smartcard RSA | 1,084 | April 1, 2020, 10:22 a.m. |
| Polyhomophonic Substitution — Part 2 | 2,000 | March 28, 2020, 5:30 p.m. |
| The SIGABA Challenge — Part 5 | 20,000 | March 26, 2020, 9:39 p.m. |
| RSA Factoring Challenge: RSA-232 | 0 | March 25, 2020, 1:36 p.m. |
| The T52 Sturgeon Challenge — Part 12 | 1,181 | March 23, 2020, 11:23 p.m. |
| The T52 Sturgeon Challenge — Part 10 | 1,181 | March 23, 2020, 4:25 p.m. |
| The T52 Sturgeon Challenge — Part 7 | 1,181 | March 23, 2020, 9:59 a.m. |
| The T52 Sturgeon Challenge — Part 6 | 1,181 | March 22, 2020, 10:48 p.m. |
| The T52 Sturgeon Challenge — Part 11 | 1,181 | March 22, 2020, 8:17 p.m. |
| The T52 Sturgeon Challenge — Part 8 | 1,181 | March 22, 2020, 1:03 p.m. |
| Polyhomophonic Substitution — Part 1 | 200 | March 22, 2020, 10:09 a.m. |
| The SIGABA Challenge — Part 2 | 1,406 | March 21, 2020, 9:49 p.m. |
| The SIGABA Challenge — Part 3 | 17,290 | March 21, 2020, 7:19 p.m. |
| The SIGABA Challenge — Part 4 | 18,390 | March 21, 2020, 5:08 p.m. |
| The SIGABA Challenge — Part 1 | 1,373 | March 21, 2020, 2:15 p.m. |
| The T52 Sturgeon Challenge — Part 9 | 1,181 | March 20, 2020, 5:08 p.m. |
| The T52 Sturgeon Challenge — Part 5 | 1,181 | March 20, 2020, 5:07 p.m. |
| The T52 Sturgeon Challenge — Part 4 | 1,177 | March 19, 2020, 10:22 p.m. |
| The T52 Sturgeon Challenge — Part 3 | 1,178 | March 18, 2020, 10:24 p.m. |
| The T52 Sturgeon Challenge — Part 2 | 1,178 | March 18, 2020, 10:23 p.m. |
| The T52 Sturgeon Challenge — Part 1 | 1,176 | March 18, 2020, 8:53 p.m. |
| RSA Factoring Challenge: RSA-250 | 0 | March 16, 2020, 10:31 p.m. |
| The LoRa Cipher: Logic Randomness — Part 1 | 2,000 | Feb. 20, 2020, 5:26 p.m. |
| Polyphonic Substitution Cipher — Part 2 | 2,000 | Jan. 14, 2020, 9:48 p.m. |
| CMEA 1 | 1,085 | Jan. 6, 2020, 3:07 p.m. |
| RSA Factoring Challenge: RSA-240 | 0 | Dec. 2, 2019, 8:05 p.m. |
| Cipher ID — Part 1 | 1,444 | Dec. 2, 2019, 11:48 a.m. |
| Polyphonic Substitution Cipher — Part 1 | 1,725 | Nov. 23, 2019, 9:47 p.m. |
| "The Road" — Part 1 | 1,160 | Nov. 14, 2019, 9:04 p.m. |
| Breaking a Filter Generator | 1,156 | Oct. 5, 2019, 9:29 a.m. |
| Heartbleed — Part 3 | 1,100 | Sept. 26, 2019, 9:57 a.m. |
| Heartbleed — Part 1 | 100 | Sept. 26, 2019, 9:53 a.m. |
| A Cloaked Substitution Cipher — Part 2 | 2,000 | Aug. 26, 2019, 1:58 a.m. |
| A Cloaked Substitution Cipher — Part 1 | 2,000 | Aug. 21, 2019, 7:03 p.m. |
| Homophonic Encryption — Part 2 | 1,725 | May 10, 2019, 10:29 p.m. |
| Homophonic Encryption — Part 4 | 2,000 | May 9, 2019, 2:10 p.m. |
| Homophonic Encryption — Part 3 | 2,000 | May 9, 2019, 1:48 p.m. |
| Homophonic Encryption — Part 1 | 2,000 | May 4, 2019, 8:15 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 102 | March 10, 2019, 1:49 p.m. |
| Weakened Handycipher — Part 1 | 1,108 | March 6, 2019, 1:55 p.m. |
| Handycipher made in love — Part 1 | 1,824 | Feb. 17, 2019, 7:03 p.m. |
| Monoalphabetic Substitution with Nostradamus Flavor | 1,824 | Feb. 17, 2019, 5:11 p.m. |
| Trendy Messenger | 1,199 | Nov. 23, 2018, 4:13 p.m. |
| RSA Factoring Challenge: RSA-230 | 0 | Nov. 10, 2018, 11:19 p.m. |
| Cryptanalysis Hacking Puzzles — Part 1 | 150 | Oct. 28, 2018, 5:45 p.m. |
| Modular Sequences | 200 | Sept. 25, 2018, 5:05 p.m. |
| Autokey Cipher | 200 | Sept. 25, 2018, 4:08 p.m. |
| Number Sequence — Part 5 | 100 | Aug. 29, 2018, 12:50 p.m. |
| Unusual encryption using a diophantine equation | 1,092 | July 16, 2018, 4:40 p.m. |
| Summer Job | 1,330 | July 13, 2018, 9:05 p.m. |
| Fastest in the West | 1,469 | June 22, 2018, 10:48 p.m. |
| Number Sequence — Part 10 | 200 | April 19, 2018, 10:02 a.m. |
| Number Sequence — Part 9 | 101 | Feb. 23, 2018, 5:46 p.m. |
| The Einstein Enigma | 2,000 | Feb. 8, 2018, 9:10 p.m. |
| Advent Challenge — Part 4 | 1,502 | Dec. 29, 2017, 9:06 p.m. |
| Advent Challenge — Part 3 | 2,000 | Dec. 22, 2017, 9:41 p.m. |
| AES ECB Wrong Encoding | 1,824 | Dec. 17, 2017, 9:48 p.m. |
| Advent-Challenge — Part 2 | 2,000 | Dec. 17, 2017, 1:08 p.m. |
| Advent-Challenge — Part 1 | 150 | Dec. 10, 2017, 2:33 p.m. |
| Number Sequence — Part 7 | 100 | Sept. 13, 2017, 1:39 p.m. |
| Molehunt (Part 3/3) | 1,095 | Dec. 18, 2016, 4:12 p.m. |
| RSA Factoring Challenge: RSA-220 | 0 | Dec. 1, 2016, 4:20 p.m. |
| ASAC — A Strong(er) ADFGVX Cipher — Part 1 | 2,000 | July 10, 2016, 6:57 p.m. |
| Pigpen with a twist — Part 2 | 1,105 | Dec. 1, 2015, 3:38 p.m. |
| News from Castle Mansfeld | 200 | Nov. 13, 2015, 3:30 p.m. |
| Weakened Granit — Part 1 | 200 | Sept. 24, 2015, 1:14 p.m. |
| M-138 — Part 3 | 1,172 | Sept. 18, 2015, 1:31 p.m. |
| Number Sequence — Part 8 | 200 | Sept. 14, 2015, 1:37 p.m. |
| A really long number sequence | 1,109 | April 15, 2015, 7:11 p.m. |
| Number Sequence — Part 6 | 200 | March 23, 2015, 1:02 p.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,106 | Feb. 27, 2015, 1:45 p.m. |
| M-138 — Part 2 | 2,000 | Dec. 24, 2014, 9:51 p.m. |
| M-138 — Part 1 | 200 | Dec. 24, 2014, 2:45 p.m. |
| RSA Factoring Challenge: RSA-210 | 0 | Nov. 10, 2014, 6:11 p.m. |
| RSA Factoring Challenge: RSA-704 | 0 | Nov. 10, 2014, 6:06 p.m. |
| The Last Note | 200 | Sept. 23, 2014, 4:49 p.m. |
| Factorization Cipher — Part 2 | 1,118 | Sept. 12, 2014, 2:11 p.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | July 16, 2014, 12:27 p.m. |
| Enigma Part 1 | 1,108 | July 16, 2014, 12:26 p.m. |
| Double Column Transposition — Part 3 | 1,254 | July 13, 2014, 11:30 p.m. |
| Double Column Transposition — Part 1 | 1,234 | July 9, 2014, 12:13 p.m. |
| Enigma Messages | 100 | June 27, 2014, 9:15 a.m. |
| Spanish Strip Cipher — Part 2 | 1,238 | June 26, 2014, 11:58 a.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,122 | June 25, 2014, 2:44 p.m. |
| Pigpen with a twist — Part 3 | 1,117 | June 19, 2014, 5:30 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,109 | June 18, 2014, 6:24 p.m. |
| Zodiac Cipher | 100 | June 15, 2014, 7:08 p.m. |
| Monoalphabetic Substitution with Camouflage — Part 5 | 1,125 | June 15, 2014, 3:52 p.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,121 | June 13, 2014, 12:41 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,121 | June 11, 2014, 7:24 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | June 6, 2014, 4:17 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 101 | June 6, 2014, 1:45 p.m. |
| Enigma Part 2 | 1,109 | June 6, 2014, 12:50 p.m. |
| RSA: Two different keys — same ciphertext | 1,117 | June 6, 2014, 10:02 a.m. |
| Music Code — Part 1 | 100 | June 3, 2014, 11:19 a.m. |
| Music Code — Part 2 | 1,115 | June 3, 2014, 11:19 a.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,109 | May 27, 2014, 8:36 a.m. |
| Double Column Transposition — Part 4 | 2,000 | May 20, 2014, 8:53 a.m. |
| Double Column Transposition — Part 2 | 1,547 | May 9, 2014, 10:33 a.m. |
| Kaskade-S/T — Part 1 | 100 | April 8, 2014, 11:37 a.m. |
| Spanish Strip Cipher — Part 1 | 1,613 | March 31, 2014, 7:52 p.m. |
| Classical Ciphers^3 | 100 | March 13, 2014, 5:25 p.m. |
| Factorization Cipher — Part 3 | 1,126 | March 13, 2014, 5:01 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 200 | March 6, 2014, 12:03 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 200 | March 6, 2014, 10:31 a.m. |
| Strange Message from Thessaloniki | 100 | Dec. 3, 2013, 2:27 p.m. |
| ECDH-Key Exchange for Beginners | 100 | Nov. 20, 2013, 5:48 p.m. |
| Trifid Cipher | 200 | Oct. 29, 2013, 11:28 a.m. |
| Hybrid Encryption I | 1,116 | Oct. 10, 2013, 7:42 p.m. |
| Alice's Birthday Party (Part 2) | 1,115 | Oct. 7, 2013, 4:13 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,125 | Oct. 7, 2013, 3:04 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 109 | Oct. 7, 2013, 10:21 a.m. |
| From Russia with Love | 200 | Sept. 4, 2013, 5:09 p.m. |
| Keyshanc — Part 2 | 1,149 | Aug. 8, 2013, 11:10 p.m. |
| Nils away on travel | 200 | Aug. 8, 2013, 6:28 p.m. |
| Keyshanc — Part 1 | 1,149 | Aug. 7, 2013, 7:30 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Aug. 5, 2013, 10:46 a.m. |
| Alice's Birthday Party (Part 1) | 1,120 | May 23, 2013, 9:10 a.m. |
| Modified Caesar Cipher | 100 | May 21, 2013, 7:42 a.m. |
| BCR code (Book-Caesar-RSA) | 1,176 | May 20, 2013, 12:46 p.m. |
| How do you become a big cryptographer? | 100 | May 19, 2013, 5:43 p.m. |
| ADFGVX — Part 1 | 100 | May 12, 2013, 10:06 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | April 28, 2013, 7:37 p.m. |
| Snow White and the seven dwarfs | 120 | April 25, 2013, 9:57 a.m. |
| Recycled One-Time Pad | 101 | April 17, 2013, 3:58 p.m. |
| Cracking SHA1-Hashed Passwords | 1,128 | April 16, 2013, 6:32 p.m. |
| One-Time Pad with Flaws | 100 | April 15, 2013, 6:08 p.m. |
| Double Columnar Transposition | 100 | March 18, 2013, 1:17 p.m. |
| Turing Bombe Enigma I | 100 | March 14, 2013, 10:25 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | March 12, 2013, 2:30 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | March 12, 2013, 2:30 p.m. |
| Molehunt (Part 2/3) | 100 | March 8, 2013, 1:22 p.m. |
| Molehunt (Part 1/3) | 100 | March 8, 2013, 12:34 p.m. |
| Cascading Encryption — Part 1/3 | 102 | March 8, 2013, 12:09 p.m. |
| Reserve Hand Procedure — Part 1 | 200 | March 7, 2013, 1:12 p.m. |
| Monoalphabetic Substitution | 100 | Feb. 24, 2013, 5:29 p.m. |
| A Secret Message from Castle Mansfeld | 100 | Feb. 24, 2013, 4:22 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Feb. 19, 2013, 1:27 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Feb. 12, 2013, 11:22 a.m. |
| Grille Cipher | 100 | Feb. 3, 2013, 3:30 p.m. |
| Ku Klux Klan | 1,000 | Feb. 2, 2013, 8:57 p.m. |
| ADFGVX — Part 2 | 100 | Feb. 2, 2013, 6:53 p.m. |
| Multilingual Monoalphabetic Substitution | 150 | Jan. 31, 2013, 4:01 p.m. |
| Playfair Encryption | 100 | Jan. 28, 2013, 6:13 p.m. |
| Caesar Encryption | 100 | Jan. 28, 2013, 5:27 p.m. |
| Letter to the Templars — Part 3 | 1,223 | Jan. 28, 2013, 3:57 p.m. |
| The Book Code: A Challenge for Bookworms | 100 | Jan. 28, 2013, 3:56 p.m. |
| Playfair with hints about the grid | 108 | Jan. 28, 2013, 3:55 p.m. |
| Pigpen with a twist — Part 1 | 100 | Jan. 28, 2013, 3:47 p.m. |
| Original Caesar Cipher | 100 | Jan. 28, 2013, 3:47 p.m. |
| Number Sequence — Part 4 | 100 | Jan. 28, 2013, 3:46 p.m. |
| Number Sequence — Part 3 | 100 | Jan. 28, 2013, 3:46 p.m. |
| Number Sequence — Part 2 | 100 | Jan. 28, 2013, 3:45 p.m. |
| Number Sequence | 100 | Jan. 28, 2013, 3:45 p.m. |
| ¿No Hablas Español? No problemo! | 100 | Jan. 28, 2013, 3:44 p.m. |
| Letter to the Templars — Part 2 | 101 | Jan. 28, 2013, 3:36 p.m. |
| Letter to the Templars — Part 1 | 101 | Jan. 28, 2013, 3:36 p.m. |
| Factorization Cipher — Part 1 | 100 | Jan. 28, 2013, 3:34 p.m. |
| Beaver Code | 101 | Jan. 28, 2013, 3:16 p.m. |
| A hidden word | 104 | Jan. 28, 2013, 3:14 p.m. |
Gold7
Silver11
Bronze13
