| Enigma Messages | 100 | Sept. 23, 2023, 2:16 p.m. |
| Trifid Cipher | 100 | July 12, 2023, 2:45 a.m. |
| Number Sequence — Part 10 | 100 | July 9, 2023, 1:06 a.m. |
| Fastest in the West | 1,101 | March 29, 2023, midnight |
| Unconcealed RSA messages | 1,080 | March 25, 2023, 4:45 p.m. |
| Number Sequence | 100 | Dec. 17, 2022, 6:39 p.m. |
| The Syllabary Cipher – Part 1 | 200 | Oct. 28, 2022, 8:44 p.m. |
| Merkle-Hellman Knapsack Challenge - Part 1 | 200 | Oct. 15, 2022, 4:31 a.m. |
| Modified Caesar Cipher | 100 | Aug. 6, 2022, 9:53 p.m. |
| Caesar Encryption | 100 | Aug. 6, 2022, 2:56 a.m. |
| Snow White and the seven dwarfs | 100 | July 9, 2022, 6:17 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,082 | July 3, 2022, 11:55 p.m. |
| Cracking SHA1-Hashed Passwords | 1,080 | July 3, 2022, 7:50 p.m. |
| Smartcard RSA | 1,080 | April 15, 2022, 7:42 p.m. |
| The Book Code: A Challenge for Bookworms | 100 | April 14, 2022, 12:11 a.m. |
| Nils away on travel | 100 | April 2, 2022, 10:10 p.m. |
| Alberti Challenge — Part 1 | 200 | March 27, 2022, 2:59 p.m. |
| The Last Note | 100 | March 15, 2022, 12:25 a.m. |
| Number Sequence — Part 8 | 100 | March 2, 2022, 2:16 p.m. |
| ECDH-Key Exchange for Beginners | 100 | Feb. 18, 2022, 10:13 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,080 | Feb. 16, 2022, 11:55 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Feb. 14, 2022, 11:06 p.m. |
| Modular Sequences | 100 | Feb. 12, 2022, 5:31 p.m. |
| Advent-Challenge — Part 1 | 100 | Feb. 4, 2022, 7:44 p.m. |
| BCR code (Book-Caesar-RSA) | 1,084 | Feb. 1, 2022, 2:19 a.m. |
| A hidden word | 100 | Jan. 23, 2022, 11:26 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | Jan. 21, 2022, 1:27 a.m. |
| One-Time Pad with Flaws | 100 | Oct. 24, 2021, 9:27 p.m. |
| M-138 — Part 2 | 1,093 | July 31, 2021, 11:47 a.m. |
| M-138 — Part 1 | 100 | July 24, 2021, 11:44 p.m. |
| Advent Challenge — Part 4 | 1,110 | July 22, 2021, 12:16 p.m. |
| New Year's Greetings — Part 1 | 100 | July 22, 2021, 12:11 p.m. |
| Lattice Part 1 | 1,082 | July 16, 2021, 10:40 p.m. |
| Wheatstone Cryptograph — Part 1 | 101 | July 7, 2021, 1:01 a.m. |
| Hill Cipher with Sudoku Key | 100 | July 4, 2021, 6:47 p.m. |
| Factorization Cipher — Part 3 | 1,084 | May 2, 2021, 5:38 p.m. |
| The Einstein Enigma | 1,113 | April 18, 2021, 2:58 p.m. |
| Molehunt (Part 2/3) | 100 | April 12, 2021, 5:48 p.m. |
| Molehunt (Part 1/3) | 100 | April 12, 2021, 3:12 a.m. |
| Monoalphabetic Substitution | 100 | April 7, 2021, 1:10 p.m. |
| Autokey Cipher | 100 | March 20, 2021, 8:07 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Feb. 22, 2021, 1:59 p.m. |
| Factorization Cipher — Part 2 | 1,085 | Feb. 11, 2021, 4:35 p.m. |
| Factorization Cipher — Part 1 | 100 | Jan. 26, 2021, 7:24 p.m. |
| Advent Challenge — Part 3 | 1,115 | Dec. 26, 2020, 2:21 p.m. |
| AES ECB Wrong Encoding | 1,120 | July 26, 2020, 1:55 a.m. |
| Lightweight Introduction to Lattices — Part 3 | 1,824 | July 18, 2020, 10:43 a.m. |
| Handycipher made in love — Part 2 | 1,152 | July 4, 2020, 4:11 p.m. |
| Handycipher made in love — Part 1 | 1,144 | July 3, 2020, 12:30 p.m. |
| Trendy Messenger | 1,406 | June 29, 2018, 10:26 a.m. |
| Summer Job | 1,433 | June 26, 2018, 1:36 a.m. |
| Alice's Birthday Party (Part 2) | 1,089 | May 17, 2018, 2:28 a.m. |
| Advent-Challenge — Part 2 | 1,203 | May 17, 2018, 1:25 a.m. |
| Alice's Birthday Party (Part 1) | 1,089 | May 15, 2018, 10:35 p.m. |
| RSA: Two different keys — same ciphertext | 1,092 | May 9, 2018, 12:56 a.m. |
| Broadcasting and low exponent — RSA Attack | 1,092 | May 7, 2018, 3:02 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Nov. 26, 2017, 3:37 a.m. |
| Letter to the Templars — Part 2 | 100 | Oct. 29, 2017, 3:50 a.m. |
| Letter to the Templars — Part 3 | 1,100 | Oct. 29, 2017, 3:35 a.m. |
| Letter to the Templars — Part 1 | 100 | Oct. 29, 2017, 12:40 a.m. |
| Beaver Code | 100 | April 23, 2017, 7:35 p.m. |
| Number Sequence — Part 2 | 100 | April 23, 2017, 7:34 p.m. |
| Original Caesar Cipher | 100 | Dec. 5, 2012, 1:39 a.m. |