| Enigma Messages with Repeated Letters — Part 3 | 100 | June 5, 2022, 10:02 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | June 5, 2022, 8:29 p.m. |
| The Last Note | 100 | June 5, 2022, 10:45 a.m. |
| Hill Cipher with Sudoku Key | 100 | June 5, 2022, 10:08 a.m. |
| Alberti Challenge — Part 1 | 101 | June 4, 2022, 9 a.m. |
| Enigma Combinatorics | 100 | June 4, 2022, 8:22 a.m. |
| Lightweight Introduction to Lattices — Part 1 | 100 | Aug. 19, 2021, 3:48 p.m. |
| AES ECB Wrong Encoding | 1,109 | Aug. 17, 2021, 9:58 p.m. |
| BCR code (Book-Caesar-RSA) | 1,085 | Aug. 16, 2021, 7:10 p.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,084 | Aug. 14, 2021, 2:26 p.m. |
| Not-so-Secret Message from Malawi — Part II (ECC) | 1,081 | Aug. 13, 2021, 8:01 p.m. |
| Modular Sequences | 100 | Dec. 20, 2020, 10:37 p.m. |
| Fastest in the West | 1,121 | Dec. 20, 2020, 11:20 a.m. |
| Summer Job | 1,122 | Nov. 19, 2020, 9:40 p.m. |
| Molehunt (Part 3/3) | 1,083 | Nov. 18, 2020, 6:47 p.m. |
| Recycled One-Time Pad | 100 | Nov. 18, 2020, 3:16 p.m. |
| M-138 — Part 3 | 1,096 | Nov. 18, 2020, 1:01 p.m. |
| Number Sequence — Part 10 | 100 | Nov. 17, 2020, 10:39 p.m. |
| Enigma Part 2 | 1,083 | Nov. 17, 2020, 3:32 p.m. |
| Cryptanalysis Hacking Puzzles — Part 1 | 100 | Sept. 4, 2020, 4 p.m. |
| Unconcealed RSA messages | 1,086 | Aug. 30, 2020, 12:24 p.m. |
| Double Columnar Transposition | 100 | Aug. 26, 2020, 2:24 p.m. |
| Nils away on travel | 100 | Aug. 26, 2020, 1:27 p.m. |
| Playfair with hints about the grid | 100 | Aug. 8, 2020, 12:01 p.m. |
| Playfair Encryption | 100 | Aug. 8, 2020, 11:39 a.m. |
| Partial Key Exposure with RSA — Part 1 | 1,087 | Aug. 7, 2020, 6:54 p.m. |
| Smartcard RSA | 1,083 | Aug. 7, 2020, 5:49 p.m. |
| ECDH-Key Exchange for Beginners | 100 | Aug. 6, 2020, 9:04 p.m. |
| Pigpen with a twist — Part 1 | 100 | Aug. 5, 2020, 9:38 p.m. |
| Autokey Cipher | 100 | Aug. 4, 2020, 11:04 p.m. |
| Molehunt (Part 2/3) | 100 | Aug. 4, 2020, 6:16 p.m. |
| Molehunt (Part 1/3) | 100 | Aug. 4, 2020, 4:53 p.m. |
| Enigma Part 1 | 1,083 | Aug. 4, 2020, 11:01 a.m. |
| RSA: Two different keys — same ciphertext | 1,085 | Aug. 3, 2020, 5:48 p.m. |
| Number Sequence — Part 8 | 100 | Aug. 3, 2020, 10:14 a.m. |
| Number Sequence — Part 4 | 100 | Aug. 3, 2020, 10:01 a.m. |
| ¿No Hablas Español? No problemo! | 100 | July 22, 2020, 4:29 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | July 22, 2020, 3:45 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | July 22, 2020, 3:11 p.m. |
| Hybrid Encryption I | 1,083 | July 22, 2020, 1:01 p.m. |
| Lightweight Introduction to Lattices — Part 3 | 1,576 | July 22, 2020, 12:14 p.m. |
| Lattice Part 1 | 1,084 | July 22, 2020, 10:54 a.m. |
| M-138 — Part 2 | 1,097 | July 17, 2020, 11:33 a.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | July 17, 2020, 10:14 a.m. |
| M-138 — Part 1 | 100 | July 15, 2020, 6:26 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | July 15, 2020, 5:23 p.m. |
| How do you become a big cryptographer? | 100 | July 15, 2020, 3:50 p.m. |
| Modified Caesar Cipher | 100 | July 15, 2020, 3:24 p.m. |
| From Russia with Love | 100 | July 15, 2020, 1:13 p.m. |
| Snow White and the seven dwarfs | 100 | July 15, 2020, 11:35 a.m. |
| Factorization Cipher — Part 3 | 1,086 | July 15, 2020, 10:52 a.m. |
| Number Sequence — Part 3 | 100 | July 8, 2020, 4:09 p.m. |
| Factorization Cipher — Part 2 | 1,086 | July 6, 2020, 5:21 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,083 | July 6, 2020, 11:42 a.m. |
| One-Time Pad with Flaws | 100 | July 5, 2020, 3:33 p.m. |
| Advent-Challenge — Part 1 | 100 | July 5, 2020, 2:59 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | July 3, 2020, 8:05 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | July 3, 2020, 7:50 p.m. |
| Grille Cipher | 100 | July 3, 2020, 5:54 p.m. |
| Factorization Cipher — Part 1 | 100 | July 3, 2020, 4:50 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | July 3, 2020, 4:17 p.m. |
| Monoalphabetic Substitution | 100 | July 1, 2020, 10:40 p.m. |
| Letter to the Templars — Part 3 | 1,089 | July 1, 2020, 5:29 p.m. |
| A hidden word | 100 | July 1, 2020, 5:17 p.m. |
| Letter to the Templars — Part 2 | 100 | July 1, 2020, 5:10 p.m. |
| Letter to the Templars — Part 1 | 100 | July 1, 2020, 5:03 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,083 | July 1, 2020, 4:55 p.m. |
| Alice's Birthday Party (Part 2) | 1,083 | July 1, 2020, 11:46 a.m. |
| Alice's Birthday Party (Part 1) | 1,083 | June 29, 2020, 10:19 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,085 | June 29, 2020, 8:09 p.m. |
| Beaver Code | 100 | June 28, 2020, 10:51 p.m. |
| Caesar Encryption | 100 | June 28, 2020, 7:33 p.m. |
| Original Caesar Cipher | 100 | June 28, 2020, 6:31 p.m. |
| Cracking SHA1-Hashed Passwords | 1,085 | June 28, 2020, 6:09 p.m. |
| Number Sequence — Part 2 | 100 | June 28, 2020, 6:06 p.m. |
| Number Sequence | 100 | June 28, 2020, 6:03 p.m. |
Gold0
Silver0
Bronze0
