| Find the right route — Part 3 | 103 | Jan. 24, 2021, 9:22 p.m. |
| Find the right route — Part 2 | 103 | Jan. 24, 2021, 9:21 p.m. |
| Spirale — Part 3 | 1,098 | Jan. 19, 2021, 7:45 p.m. |
| Spirale — Part 2 | 1,098 | Jan. 19, 2021, 7:44 p.m. |
| Spirale — Part 1 | 1,098 | Jan. 19, 2021, 7:42 p.m. |
| ElsieFour — Part 1 | 13,586 | Jan. 4, 2021, 7:14 p.m. |
| Lightweight Introduction to Lattices — Part 3 | 1,198 | Dec. 29, 2020, 7:46 p.m. |
| Lightweight Introduction to Lattices — Part 2 | 101 | Dec. 29, 2020, 7:43 p.m. |
| Lightweight Introduction to Lattices — Part 1 | 100 | Dec. 29, 2020, 7:42 p.m. |
| Find the right route — Part 1 | 102 | Dec. 29, 2020, 7:40 p.m. |
| Weakened ElsieFour — Part 3 | 1,113 | Dec. 29, 2020, 7:34 p.m. |
| The LoRa Cipher: Logic Randomness — Part 1 | 1,244 | May 12, 2020, 11:50 p.m. |
| Polyphonic Substitution Cipher — Part 2 | 1,222 | May 6, 2020, 6:17 p.m. |
| Polyhomophonic Substitution — Part 3 | 1,337 | May 6, 2020, 6:16 p.m. |
| Polyhomophonic Substitution — Part 2 | 1,307 | May 6, 2020, 6:15 p.m. |
| Polyhomophonic Substitution — Part 1 | 102 | May 6, 2020, 6:13 p.m. |
| RSA Factoring Challenge: RSA-250 | 0 | May 6, 2020, 6:10 p.m. |
| RSA Factoring Challenge: RSA-232 | 0 | May 6, 2020, 6:09 p.m. |
| RSA Factoring Challenge: RSA-240 | 0 | May 6, 2020, 6:08 p.m. |
| The SIGABA Challenge — Part 4 | 16,438 | April 8, 2020, 6:24 p.m. |
| The SIGABA Challenge — Part 3 | 16,839 | March 26, 2020, 5:58 p.m. |
| The SIGABA Challenge — Part 2 | 1,378 | March 26, 2020, 5:57 p.m. |
| The SIGABA Challenge — Part 1 | 1,349 | March 26, 2020, 5:55 p.m. |
| Weakened ElsieFour — Part 1 | 1,138 | Nov. 28, 2019, 7:27 p.m. |
| Polyphonic Substitution Cipher — Part 1 | 1,725 | Nov. 23, 2019, 10:47 p.m. |
| Cipher ID — Part 1 | 2,000 | Nov. 20, 2019, 12:40 a.m. |
| A Cloaked Substitution Cipher — Part 2 | 2,000 | Aug. 26, 2019, 12:10 a.m. |
| A Cloaked Substitution Cipher — Part 1 | 2,000 | Aug. 21, 2019, 7:03 p.m. |
| The T52 Sturgeon Challenge — Part 11 | 1,660 | Aug. 14, 2019, 5:05 p.m. |
| The T52 Sturgeon Challenge — Part 12 | 1,660 | Aug. 14, 2019, 4:54 p.m. |
| The T52 Sturgeon Challenge — Part 8 | 1,660 | Aug. 14, 2019, 6:40 a.m. |
| The T52 Sturgeon Challenge — Part 7 | 1,725 | Aug. 13, 2019, 4:29 p.m. |
| The T52 Sturgeon Challenge — Part 6 | 1,725 | Aug. 13, 2019, 12:21 a.m. |
| The T52 Sturgeon Challenge — Part 5 | 1,824 | Aug. 12, 2019, 4:35 p.m. |
| The T52 Sturgeon Challenge — Part 4 | 1,385 | Aug. 11, 2019, 8:05 p.m. |
| The T52 Sturgeon Challenge — Part 3 | 1,824 | July 24, 2019, 6:19 a.m. |
| The T52 Sturgeon Challenge — Part 2 | 1,824 | July 24, 2019, 6:18 a.m. |
| Holographic Encryption — Part 1 | 1,124 | July 21, 2019, 4:07 p.m. |
| The T52 Sturgeon Challenge — Part 1 | 1,725 | July 16, 2019, 5:31 p.m. |
| Handycipher — Part 10 | 2,000 | June 26, 2019, 12:28 p.m. |
| Handycipher made in love — Part 2 | 2,000 | May 21, 2019, 10:37 p.m. |
| Kaskade-S/T — Part 6 (RansomKaskade Part 1) | 1,131 | May 19, 2019, 12:39 p.m. |
| Double Column Transposition — Part 5 | 1,101 | May 14, 2019, 6:16 p.m. |
| Homophonic Encryption — Part 2 | 1,576 | May 14, 2019, 6:05 a.m. |
| Homophonic Encryption — Part 4 | 1,824 | May 10, 2019, 6:25 p.m. |
| Homophonic Encryption — Part 3 | 2,000 | May 9, 2019, 5:16 p.m. |
| Kaskade-S/T — Part 5 | 1,088 | May 8, 2019, 6:23 p.m. |
| Homophonic Encryption — Part 1 | 2,000 | May 5, 2019, 4:23 a.m. |
| Cascading Encryption — Part 3/3 | 1,095 | March 10, 2019, 3:57 p.m. |
| Cascading Encryption — Part 2/3 | 1,095 | March 8, 2019, 5:40 p.m. |
| Hilly — Part 1 | 1,127 | March 6, 2019, 5:05 p.m. |
| Not-so-Secret Message from Malawi — Part II (ECC) | 1,087 | Feb. 26, 2019, 6:04 p.m. |
| Handycipher made in love — Part 1 | 2,000 | Feb. 16, 2019, 4:30 p.m. |
| Monoalphabetic Substitution with Nostradamus Flavor | 2,000 | Feb. 16, 2019, 3:57 p.m. |
| Extended Handycipher — Part 6 | 13,701 | Jan. 28, 2019, 6:39 p.m. |
| Handycipher — Part 9 | 13,830 | Jan. 26, 2019, 5:57 p.m. |
| Handycipher — Part 8 | 13,830 | Jan. 26, 2019, 9:32 a.m. |
| Handycipher — Part 7 | 13,830 | Jan. 26, 2019, 7:53 a.m. |
| Extended Handycipher — Part 5 | 13,704 | Jan. 22, 2019, 6:27 a.m. |
| "The Road" — Part 1 | 1,315 | Jan. 14, 2019, 8:37 a.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 150 | Jan. 10, 2019, 10:13 p.m. |
| Extended Handycipher — Part 4 | 13,725 | Dec. 14, 2018, 6:34 a.m. |
| Extended Handycipher — Part 3 | 1,109 | Nov. 16, 2018, 5:12 p.m. |
| Extended Handycipher — Part 2 | 1,109 | Nov. 13, 2018, 8:07 p.m. |
| Extended Handycipher — Part 1 | 1,109 | Nov. 10, 2018, 5:59 p.m. |
| RSA Factoring Challenge: RSA-230 | 0 | Nov. 10, 2018, 5:51 p.m. |
| Handycipher — Part 4 | 13,748 | Nov. 5, 2018, 6:48 a.m. |
| Handycipher — Part 6 | 13,748 | Nov. 4, 2018, 11:47 p.m. |
| Handycipher — Part 5 | 13,749 | Nov. 4, 2018, 1:40 p.m. |
| Handycipher — Part 3 | 13,529 | Nov. 1, 2018, 9:36 p.m. |
| Handycipher — Part 2 | 1,109 | Nov. 1, 2018, 7:59 p.m. |
| Handycipher — Part 1 | 1,109 | Nov. 1, 2018, 5:41 p.m. |
| Weakened Handycipher — Part 6 | 1,123 | Nov. 1, 2018, 12:50 a.m. |
| Weakened Handycipher — Part 5 | 1,123 | Oct. 31, 2018, 10:03 p.m. |
| Weakened Handycipher — Part 4 | 1,124 | Oct. 31, 2018, 6:18 a.m. |
| Cryptanalysis Hacking Puzzles — Part 1 | 200 | Oct. 27, 2018, 8:18 a.m. |
| Weakened Handycipher — Part 3 | 1,111 | Oct. 27, 2018, 6:27 a.m. |
| Weakened Handycipher — Part 2 | 1,111 | Oct. 27, 2018, 6:26 a.m. |
| Weakened Handycipher — Part 1 | 1,111 | Oct. 26, 2018, 7:56 a.m. |
| Akelarre Part 1 | 1,088 | Oct. 4, 2018, 7:15 a.m. |
| Modular Sequences | 133 | Sept. 28, 2018, 6:52 a.m. |
| Autokey Cipher | 133 | Sept. 28, 2018, 6:16 a.m. |
| Breaking a Filter Generator | 1,725 | Sept. 28, 2018, 2:01 a.m. |
| Sigaba Part 1 | 1,088 | Aug. 26, 2018, 1:40 p.m. |
| CMEA 2 | 13,195 | Aug. 21, 2018, 12:05 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 2 | 1,090 | July 7, 2018, 7:50 a.m. |
| Fastest in the West | 2,000 | June 13, 2018, 7:45 a.m. |
| Summer Job | 2,000 | June 13, 2018, 6:19 a.m. |
| Trendy Messenger | 2,000 | June 13, 2018, 1:04 a.m. |
| Lattice Part 1 | 1,090 | June 12, 2018, 12:08 a.m. |
| RSA Factoring Challenge: RSA-220 | 0 | April 28, 2018, 7:03 p.m. |
| RSA Factoring Challenge: RSA-704 | 0 | April 28, 2018, 12:41 p.m. |
| RSA Factoring Challenge: RSA-210 | 0 | April 27, 2018, 3:56 p.m. |
| M-138 — Part 4 | 1,112 | April 23, 2018, 12:52 p.m. |
| Number Sequence — Part 10 | 133 | April 20, 2018, 6:28 p.m. |
| The Einstein Enigma | 1,278 | April 3, 2018, 12:25 p.m. |
| Number Sequence — Part 5 | 100 | Jan. 4, 2018, 6:04 p.m. |
| An Invisible Message | 100 | Dec. 27, 2017, 10:15 a.m. |
| AES ECB Wrong Encoding | 1,523 | Dec. 24, 2017, 4:30 a.m. |
| Advent Challenge — Part 4 | 1,824 | Dec. 22, 2017, 8:43 p.m. |
| Advent Challenge — Part 3 | 2,000 | Dec. 22, 2017, 7:44 p.m. |
| Advent-Challenge — Part 2 | 1,576 | Dec. 22, 2017, 2:54 p.m. |
| Advent-Challenge — Part 1 | 200 | Dec. 9, 2017, 3:01 a.m. |
| Number Sequence — Part 9 | 150 | Nov. 18, 2017, 7:33 a.m. |
| Spanish Strip Cipher — Part 2 | 1,111 | Sept. 7, 2017, 5:37 p.m. |
| Monoalphabetic Substitution with Camouflage — Part 5 | 1,097 | Sept. 6, 2017, 7:03 a.m. |
| Ku Klux Klan | 1,000 | Sept. 4, 2017, 1:09 p.m. |
| Purple 1 | 1,092 | Sept. 3, 2017, 12:15 p.m. |
| An 'unhearable' message | 100 | Aug. 26, 2017, 6:20 p.m. |
| Number Sequence — Part 7 | 100 | Aug. 26, 2017, 7:14 a.m. |
| Multilingual Monoalphabetic Substitution | 100 | Aug. 26, 2017, 7:11 a.m. |
| Pigpen with a twist — Part 2 | 1,095 | Aug. 26, 2017, 1:48 a.m. |
| Typex — Part 2 | 1,104 | Aug. 25, 2017, 6:03 a.m. |
| Typex — Part 1 | 1,103 | Aug. 24, 2017, 6:35 p.m. |
| ASAC — A Strong(er) ADFGVX Cipher — Part 1 | 1,152 | Aug. 22, 2017, 6:15 p.m. |
| Double Column Transposition — Part 3 | 1,112 | Aug. 22, 2017, 6:13 p.m. |
| Double Column Transposition — Part 2 | 1,112 | Aug. 22, 2017, 6:11 p.m. |
| Pigpen with a twist — Part 3 | 1,095 | Aug. 20, 2017, 3:36 a.m. |
| Kaskade-S/T — Part 3 | 1,093 | Aug. 19, 2017, 10:34 p.m. |
| ORYX Stream Cipher — Part 4a | 1,112 | Aug. 12, 2017, 6:29 a.m. |
| M-138 — Part 3 | 1,119 | Aug. 12, 2017, 5:24 a.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,097 | Aug. 10, 2017, 7:15 a.m. |
| Music Code — Part 2 | 1,094 | Aug. 9, 2017, 5:07 p.m. |
| Music Code — Part 1 | 100 | Aug. 9, 2017, 5:02 p.m. |
| Flawed Usage of a OTP Cipher by the BND | 1,130 | Aug. 8, 2017, 10:49 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,097 | July 29, 2017, 6 p.m. |
| Keyshanc — Part 2 | 1,099 | July 29, 2017, 7:28 a.m. |
| Keyshanc — Part 1 | 1,099 | July 29, 2017, 7:27 a.m. |
| Double Column Transposition — Part 4 | 1,113 | July 29, 2017, 1:56 a.m. |
| Double Column Transposition — Part 1 | 1,112 | July 28, 2017, 11:13 p.m. |
| Unconcealed RSA messages | 1,096 | July 28, 2017, 5:59 p.m. |
| Smartcard RSA | 1,092 | July 27, 2017, 6:09 p.m. |
| CMEA 1 | 1,093 | July 25, 2017, 3:14 p.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,093 | July 18, 2017, 6:37 p.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | July 15, 2017, 6:22 p.m. |
| Unusual encryption using a diophantine equation | 1,096 | July 14, 2017, 6:36 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,098 | July 12, 2017, 6:19 p.m. |
| Molehunt (Part 3/3) | 1,092 | July 12, 2017, 6:11 p.m. |
| Heartbleed — Part 3 | 1,117 | July 10, 2017, 7:39 p.m. |
| Kaskade-S/T — Part 2 | 1,094 | July 10, 2017, 7:21 p.m. |
| BCR code (Book-Caesar-RSA) | 1,101 | July 9, 2017, 7:16 p.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,098 | July 9, 2017, 7:12 a.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | July 8, 2017, 9:04 p.m. |
| Factorization Cipher — Part 3 | 1,097 | July 6, 2017, 10:19 p.m. |
| Kaskade-S/T — Part 1 | 100 | July 5, 2017, 9:41 p.m. |
| A really long number sequence | 1,096 | July 5, 2017, 9:37 p.m. |
| Enigma Part 2 | 1,092 | July 5, 2017, 1:32 a.m. |
| Enigma Part 1 | 1,092 | July 5, 2017, 1:06 a.m. |
| RSA: Two different keys — same ciphertext | 1,096 | July 2, 2017, 3:46 a.m. |
| ORYX Stream Cipher — Part 3 (revised) | 1,106 | June 28, 2017, 6:03 a.m. |
| ORYX Stream Cipher Part II | 1,092 | June 27, 2017, 5:20 p.m. |
| ORYX Stream Cipher Part I | 1,092 | June 27, 2017, 5:18 p.m. |
| Zodiac Cipher | 100 | June 26, 2017, 7:43 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | June 26, 2017, 7:41 p.m. |
| ECDH-Key Exchange for Beginners | 100 | June 25, 2017, 8:59 a.m. |
| Spanish Strip Cipher — Part 1 | 1,113 | June 23, 2017, 6:30 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,092 | June 23, 2017, 2:09 p.m. |
| Playfair with hints about the grid | 100 | June 22, 2017, 10:32 a.m. |
| Playfair Encryption | 100 | June 22, 2017, 10:31 a.m. |
| A hidden word — Part 2 | 100 | June 22, 2017, 10:28 a.m. |
| Turing Bombe Enigma I | 100 | June 21, 2017, 7:26 p.m. |
| Heartbleed — Part 2 | 100 | June 21, 2017, 3:14 p.m. |
| Enigma Messages | 100 | June 21, 2017, 12:37 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | June 21, 2017, 12:36 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | June 21, 2017, 12:35 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | June 21, 2017, 12:35 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | June 21, 2017, 12:34 p.m. |
| ADFGVX — Part 2 | 100 | June 21, 2017, 12:33 p.m. |
| ADFGVX — Part 1 | 100 | June 21, 2017, 12:32 a.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | June 20, 2017, 3:57 p.m. |
| Enigma Combinatorics | 100 | June 20, 2017, 2:54 p.m. |
| Image Noise | 100 | June 20, 2017, 11:40 a.m. |
| News from Castle Mansfeld | 100 | June 20, 2017, 11:36 a.m. |
| A Secret Message from Castle Mansfeld | 100 | June 20, 2017, 11:35 a.m. |
| The Last Note | 100 | June 19, 2017, 12:32 p.m. |
| Strange Message from Thessaloniki | 100 | June 19, 2017, 12:05 p.m. |
| New Year's Greetings — Part 5 | 1,148 | June 18, 2017, 8 p.m. |
| New Year's Greetings — Part 3 | 100 | June 18, 2017, 3:13 p.m. |
| New Year's Greetings — Part 4 | 100 | June 18, 2017, 3:06 p.m. |
| New Year's Greetings — Part 2 | 100 | June 18, 2017, 7:52 a.m. |
| New Year's Greetings — Part 1 | 100 | June 18, 2017, 7:36 a.m. |
| Pigpen with a twist — Part 1 | 100 | June 18, 2017, 6:25 a.m. |
| Trifid Cipher | 100 | June 18, 2017, 3:41 a.m. |
| Weakened Granit — Part 1 | 100 | June 17, 2017, 11:20 p.m. |
| Hill Cipher with Sudoku Key | 100 | June 17, 2017, 4 p.m. |
| Double Columnar Transposition | 100 | June 17, 2017, 2:44 p.m. |
| M-138 — Part 2 | 1,122 | June 17, 2017, 12:39 a.m. |
| Heartbleed — Part 1 | 100 | June 16, 2017, 8:23 p.m. |
| M-138 — Part 1 | 100 | June 16, 2017, 3:11 a.m. |
| Hybrid Encryption I | 1,093 | June 16, 2017, 2:23 a.m. |
| Factorization Cipher — Part 2 | 1,097 | June 15, 2017, 7:56 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,092 | June 13, 2017, 7:45 p.m. |
| Classical Ciphers^3 | 100 | June 13, 2017, 1:21 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | June 13, 2017, 6:05 a.m. |
| Reserve Hand Procedure — Part 1 | 100 | June 13, 2017, 3:17 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | June 13, 2017, 2:20 a.m. |
| One-Time Pad with Flaws | 100 | June 13, 2017, 12:34 a.m. |
| Broadcasting and low exponent — RSA Attack | 1,096 | June 12, 2017, 8:37 p.m. |
| Alice's Birthday Party (Part 2) | 1,092 | June 12, 2017, 6:34 p.m. |
| Alice's Birthday Party (Part 1) | 1,092 | June 12, 2017, 8:55 a.m. |
| How do you become a big cryptographer? | 100 | June 11, 2017, 10:45 p.m. |
| Recycled One-Time Pad | 100 | June 11, 2017, 3:44 a.m. |
| From Russia with Love | 100 | June 11, 2017, 2:34 a.m. |
| Cracking SHA1-Hashed Passwords | 1,094 | June 11, 2017, 1:53 a.m. |
| Cascading Encryption — Part 1/3 | 100 | June 10, 2017, 3:40 p.m. |
| Molehunt (Part 2/3) | 100 | June 10, 2017, 2:49 p.m. |
| Molehunt (Part 1/3) | 100 | June 10, 2017, 1:55 p.m. |
| Factorization Cipher — Part 1 | 100 | June 10, 2017, 7:21 a.m. |
| Modified Caesar Cipher | 100 | June 10, 2017, 6:58 a.m. |
| The Book Code: A Challenge for Bookworms | 100 | June 10, 2017, 3:46 a.m. |
| Grille Cipher | 100 | June 10, 2017, 2:14 a.m. |
| Nils away on travel | 100 | June 10, 2017, 1:36 a.m. |
| ¿No Hablas Español? No problemo! | 100 | June 9, 2017, 11:04 p.m. |
| Snow White and the seven dwarfs | 100 | June 9, 2017, 10:13 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | June 9, 2017, 9:30 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | June 9, 2017, 9:03 p.m. |
| A hidden word | 100 | June 9, 2017, 8:35 p.m. |
| Letter to the Templars — Part 3 | 1,102 | June 9, 2017, 8:30 p.m. |
| Letter to the Templars — Part 2 | 100 | June 9, 2017, 8:18 p.m. |
| Letter to the Templars — Part 1 | 100 | June 9, 2017, 7:53 p.m. |
| Monoalphabetic Substitution | 100 | June 9, 2017, 7:02 p.m. |
| Beaver Code | 100 | June 9, 2017, 6:14 p.m. |
| Original Caesar Cipher | 100 | June 9, 2017, 6 p.m. |
| Caesar Encryption | 100 | June 9, 2017, 5:54 p.m. |
| Number Sequence — Part 4 | 100 | June 9, 2017, 4:12 p.m. |
| Number Sequence — Part 8 | 100 | June 9, 2017, 12:10 a.m. |
| Number Sequence — Part 6 | 100 | June 8, 2017, 11:55 p.m. |
| Number Sequence — Part 2 | 100 | June 8, 2017, 11:48 p.m. |
| Number Sequence — Part 3 | 100 | June 8, 2017, 9:54 p.m. |
| Number Sequence | 100 | June 8, 2017, 8:57 p.m. |