| Double Column Transposition — Part 5 | 1,096 | March 11, 2020, 8:04 a.m. |
| Number Sequence — Part 10 | 100 | Feb. 29, 2020, 12:25 p.m. |
| Autokey Cipher | 100 | Feb. 29, 2020, 11:39 a.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Feb. 29, 2020, 10:58 a.m. |
| Double Column Transposition — Part 4 | 1,096 | Feb. 25, 2020, 8:47 p.m. |
| The LoRa Cipher: Logic Randomness — Part 1 | 1,576 | Feb. 25, 2020, 7:51 a.m. |
| Double Column Transposition — Part 3 | 1,096 | Feb. 24, 2020, 9:34 p.m. |
| Double Column Transposition — Part 1 | 1,096 | Feb. 24, 2020, 9:12 p.m. |
| Double Column Transposition — Part 2 | 1,096 | Feb. 24, 2020, 7:06 p.m. |
| Image Noise | 100 | Feb. 10, 2018, 1:43 p.m. |
| RSA with Special d | 13,217 | Feb. 9, 2018, 6:01 p.m. |
| The Last Note | 100 | Feb. 9, 2018, 11:44 a.m. |
| The Einstein Enigma | 1,824 | Feb. 9, 2018, 9:40 a.m. |
| Lattice Part 1 | 1,092 | Feb. 3, 2018, 7:05 a.m. |
| New Year's Greetings — Part 4 | 100 | Dec. 25, 2017, 3:26 p.m. |
| New Year's Greetings — Part 3 | 100 | Dec. 25, 2017, 3:11 p.m. |
| New Year's Greetings — Part 2 | 100 | Dec. 25, 2017, 9:40 a.m. |
| New Year's Greetings — Part 1 | 100 | Dec. 25, 2017, 9:13 a.m. |
| Advent Challenge — Part 4 | 1,824 | Dec. 23, 2017, 11:56 a.m. |
| Advent Challenge — Part 3 | 2,000 | Dec. 23, 2017, 8:43 a.m. |
| Advent-Challenge — Part 2 | 1,660 | Dec. 20, 2017, 2:38 p.m. |
| Number Sequence — Part 9 | 103 | Dec. 16, 2017, 12:37 a.m. |
| Advent-Challenge — Part 1 | 113 | Dec. 16, 2017, 12:33 a.m. |
| Not-so-Secret Message from Malawi — Part II (ECC) | 1,092 | July 30, 2017, 7:42 a.m. |
| M-138 — Part 4 | 1,122 | June 11, 2017, 8:24 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 2 | 1,095 | June 8, 2017, 8:42 a.m. |
| ECDH-Key Exchange for Beginners | 100 | May 25, 2017, 1:56 p.m. |
| Playfair with hints about the grid | 100 | May 20, 2017, 9:37 a.m. |
| Playfair Encryption | 100 | May 20, 2017, 8:58 a.m. |
| Number Sequence — Part 7 | 100 | May 19, 2017, 2:06 p.m. |
| Number Sequence — Part 5 | 100 | May 19, 2017, 12:33 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | May 13, 2017, 7:34 a.m. |
| Turing Bombe Enigma I | 100 | May 11, 2017, 7:46 p.m. |
| Enigma Messages | 100 | May 9, 2017, 12:32 p.m. |
| Enigma Part 2 | 1,093 | May 8, 2017, 9:50 p.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | May 7, 2017, 5:54 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | May 7, 2017, 3:01 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | May 7, 2017, 1:34 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | May 7, 2017, 12:10 p.m. |
| Enigma Combinatorics | 100 | April 25, 2017, 1:49 p.m. |
| Number Sequence — Part 6 | 100 | April 25, 2017, 12:46 p.m. |
| Kaskade-S/T — Part 5 | 1,095 | April 19, 2017, 10 a.m. |
| Kaskade-S/T — Part 3 | 1,095 | April 8, 2017, 4:03 p.m. |
| Kaskade-S/T — Part 2 | 1,095 | April 6, 2017, 10:35 a.m. |
| Double Columnar Transposition | 100 | April 4, 2017, 9:28 p.m. |
| An Invisible Message | 100 | April 4, 2017, 8:33 p.m. |
| Kaskade-S/T — Part 1 | 100 | April 4, 2017, 3:02 p.m. |
| A hidden word — Part 2 | 100 | April 3, 2017, 7:25 p.m. |
| Zodiac Cipher | 100 | April 3, 2017, 7:18 p.m. |
| News from Castle Mansfeld | 100 | April 3, 2017, 1:48 p.m. |
| Smartcard RSA | 1,093 | April 2, 2017, 8 p.m. |
| BCR code (Book-Caesar-RSA) | 1,103 | April 2, 2017, 4:01 p.m. |
| Unconcealed RSA messages | 1,098 | April 2, 2017, 2:40 p.m. |
| Partial Key Exposure with RSA — Part 1 | 1,099 | March 29, 2017, 2:58 p.m. |
| CMEA 2 | 13,281 | March 29, 2017, 12:18 p.m. |
| CMEA 1 | 1,094 | March 27, 2017, 11:47 a.m. |
| Heartbleed — Part 3 | 1,120 | March 26, 2017, 9:18 a.m. |
| Heartbleed — Part 2 | 100 | March 23, 2017, 8:25 a.m. |
| Heartbleed — Part 1 | 100 | March 23, 2017, 7:37 a.m. |
| ADFGVX — Part 2 | 100 | March 22, 2017, 9:54 p.m. |
| ADFGVX — Part 1 | 100 | March 22, 2017, 9:01 p.m. |
| A really long number sequence | 1,097 | March 21, 2017, 5:50 p.m. |
| Trifid Cipher | 100 | March 21, 2017, 7:20 a.m. |
| ¿No Hablas Español? No problemo! | 100 | March 20, 2017, 7:11 p.m. |
| Molehunt (Part 2/3) | 100 | March 20, 2017, 7 p.m. |
| Enigma Part 1 | 1,093 | March 20, 2017, 6:40 p.m. |
| Molehunt (Part 1/3) | 100 | March 19, 2017, 5:51 p.m. |
| Factorization Cipher — Part 3 | 1,099 | March 19, 2017, 4 p.m. |
| Factorization Cipher — Part 2 | 1,098 | March 19, 2017, 7:14 a.m. |
| A Secret Message from Castle Mansfeld | 100 | March 18, 2017, 11:30 p.m. |
| Hybrid Encryption I | 1,094 | March 18, 2017, 7:45 a.m. |
| RSA: Two different keys — same ciphertext | 1,097 | March 18, 2017, 7:28 a.m. |
| The Book Code: A Challenge for Bookworms | 100 | March 17, 2017, 9:22 p.m. |
| Nils away on travel | 100 | March 17, 2017, 8:46 p.m. |
| Pigpen with a twist — Part 1 | 100 | March 17, 2017, 12:13 p.m. |
| M-138 — Part 3 | 1,125 | March 17, 2017, 7:37 a.m. |
| M-138 — Part 2 | 1,125 | March 15, 2017, 8:58 p.m. |
| M-138 — Part 1 | 100 | March 15, 2017, 10:54 a.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,093 | March 14, 2017, 7:47 p.m. |
| Number Sequence — Part 8 | 100 | March 14, 2017, 2:26 p.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | March 14, 2017, 2:17 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,093 | March 14, 2017, 1:53 p.m. |
| Classical Ciphers^3 | 100 | March 14, 2017, 1:11 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,097 | March 14, 2017, 8:15 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | March 13, 2017, 7:12 p.m. |
| How do you become a big cryptographer? | 100 | March 13, 2017, 6:33 p.m. |
| Reserve Hand Procedure — Part 1 | 100 | March 13, 2017, 3:29 p.m. |
| Modified Caesar Cipher | 100 | March 13, 2017, 12:06 p.m. |
| From Russia with Love | 100 | March 12, 2017, 8:52 p.m. |
| Snow White and the seven dwarfs | 100 | March 12, 2017, 6:21 p.m. |
| One-Time Pad with Flaws | 100 | March 12, 2017, 5:51 p.m. |
| Cracking SHA1-Hashed Passwords | 1,095 | March 12, 2017, 4:50 p.m. |
| Alice's Birthday Party (Part 2) | 1,093 | March 12, 2017, 2:37 p.m. |
| Alice's Birthday Party (Part 1) | 1,093 | March 12, 2017, 12:56 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | March 12, 2017, 12:45 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | March 11, 2017, 8:19 p.m. |
| Factorization Cipher — Part 1 | 100 | March 11, 2017, 7:36 p.m. |
| Grille Cipher | 100 | March 11, 2017, 7:10 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | March 10, 2017, 3 p.m. |
| Letter to the Templars — Part 3 | 1,104 | March 10, 2017, 2:33 p.m. |
| Monoalphabetic Substitution | 100 | March 10, 2017, 2:18 p.m. |
| A hidden word | 100 | March 9, 2017, 2:23 p.m. |
| Number Sequence — Part 4 | 100 | March 9, 2017, 2:18 p.m. |
| Letter to the Templars — Part 2 | 100 | March 9, 2017, 1:25 p.m. |
| Number Sequence — Part 3 | 100 | March 9, 2017, 12:49 p.m. |
| Letter to the Templars — Part 1 | 100 | March 9, 2017, 10:34 a.m. |
| Beaver Code | 100 | March 9, 2017, 9:50 a.m. |
| Caesar Encryption | 100 | March 8, 2017, 1:47 p.m. |
| Number Sequence — Part 2 | 100 | March 8, 2017, 1:36 p.m. |
| Original Caesar Cipher | 100 | March 8, 2017, 1:32 p.m. |
| Number Sequence | 100 | March 8, 2017, 1:03 p.m. |