| An Invisible Message | 100 | Aug. 22, 2023, 8:06 p.m. |
| Flawed Usage of a OTP Cipher by the BND | 1,088 | Aug. 17, 2023, 7:30 a.m. |
| Enigma Part 2 | 1,077 | Aug. 14, 2023, 5:29 p.m. |
| Turing Bombe Enigma I | 100 | Aug. 11, 2023, 2:07 a.m. |
| Enigma Messages | 100 | Aug. 11, 2023, 1:02 a.m. |
| Enigma Messages with Repeated Letters — Part 5 | 100 | Aug. 11, 2023, 12:18 a.m. |
| Enigma Messages with Repeated Letters — Part 4 | 100 | Aug. 11, 2023, 12:10 a.m. |
| Enigma Messages with Repeated Letters — Part 3 | 100 | Aug. 10, 2023, 11:59 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 100 | Aug. 10, 2023, 11:46 p.m. |
| Spanish Strip Cipher — Part 2 | 1,084 | July 26, 2023, 8:34 a.m. |
| Spanish Strip Cipher — Part 1 | 1,084 | July 26, 2023, 1:36 a.m. |
| Cascading Encryption — Part 2/3 | 1,082 | July 22, 2023, 6:10 a.m. |
| ECDH-Key Exchange for Beginners | 100 | July 13, 2023, 12:18 a.m. |
| Cascading Encryption — Part 1/3 | 100 | July 11, 2023, 3:25 p.m. |
| Pigpen with a twist — Part 2 | 1,079 | July 10, 2023, 6:52 p.m. |
| Find the right route — Part 3 | 100 | July 6, 2023, 4:01 p.m. |
| Find the right route — Part 2 | 100 | June 30, 2023, 10:42 p.m. |
| Alice's Birthday Party (Part 2) | 1,078 | April 1, 2023, 9:45 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,079 | April 1, 2023, 9:18 p.m. |
| Kaskade-S/T — Part 3 | 1,079 | March 23, 2023, 9:21 p.m. |
| Kaskade-S/T — Part 1 | 100 | March 20, 2023, 7:52 p.m. |
| Enigma Combinatorics | 100 | March 20, 2023, 6:36 p.m. |
| Double Columnar Transposition | 100 | March 19, 2023, 8:26 p.m. |
| RSA Factoring Challenge: RSA-704 | 0 | March 11, 2023, 10:35 p.m. |
| Factorization Cipher — Part 3 | 1,080 | March 11, 2023, 10:21 p.m. |
| Factorization Cipher — Part 2 | 1,080 | March 6, 2023, 12:47 a.m. |
| Polyhomophonic Substitution — Part 2 | 1,116 | Feb. 21, 2023, 1:04 a.m. |
| Polyhomophonic Substitution — Part 1 | 100 | Feb. 19, 2023, 12:14 a.m. |
| Strange Message from Thessaloniki | 100 | Feb. 16, 2023, 8:18 p.m. |
| A really long number sequence | 1,080 | Feb. 15, 2023, 8:03 p.m. |
| Keyshanc — Part 2 | 1,081 | Feb. 10, 2023, 1:45 a.m. |
| Keyshanc — Part 1 | 1,081 | Feb. 9, 2023, 11:29 p.m. |
| A Cloaked Substitution Cipher — Part 2 | 1,111 | Feb. 2, 2023, 12:07 a.m. |
| A Cloaked Substitution Cipher — Part 1 | 1,111 | Feb. 1, 2023, 4:26 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,080 | Jan. 30, 2023, 11 p.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 100 | Jan. 26, 2023, 8:17 p.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,080 | Jan. 25, 2023, 7:48 p.m. |
| News from Castle Mansfeld | 100 | Jan. 24, 2023, 12:05 a.m. |
| Ku Klux Klan | 1,000 | Jan. 22, 2023, 4:47 p.m. |
| The Syllabary Cipher – Part 5 | 1,256 | Jan. 7, 2023, 10:19 a.m. |
| The Syllabary Cipher – Part 4 | 1,256 | Jan. 7, 2023, 8:17 a.m. |
| The Syllabary Cipher – Part 3 | 1,256 | Jan. 7, 2023, 3:10 a.m. |
| The Syllabary Cipher – Part 2 | 1,258 | Jan. 6, 2023, 4:29 a.m. |
| The Syllabary Cipher – Part 1 | 101 | Jan. 6, 2023, 4:04 a.m. |
| Merkle-Hellman Knapsack Challenge - Part 1 | 101 | Jan. 6, 2023, 1:36 a.m. |
| "The Road" — Part 2 | 1,110 | June 24, 2022, 4:46 a.m. |
| "The Road" — Part 1 | 1,110 | June 17, 2022, 11:15 p.m. |
| Monoalphabetic Substitution with Nostradamus Flavor | 1,112 | June 8, 2022, 1:34 a.m. |
| ADFGVX — Part 2 | 100 | June 7, 2022, 2:11 a.m. |
| Pigpen with a twist — Part 3 | 1,081 | May 10, 2022, 11:07 p.m. |
| Double Column Transposition — Part 4 | 1,088 | May 9, 2022, 11:45 p.m. |
| Trifid Cipher | 100 | May 9, 2022, 7:02 p.m. |
| The SZ42 Challenge — Part 5 | 1,136 | May 6, 2022, 11:46 p.m. |
| The SZ42 Challenge — Part 4 | 1,135 | May 6, 2022, 11:31 p.m. |
| Cracking SHA1-Hashed Passwords | 1,081 | May 4, 2022, 11:35 p.m. |
| The SZ42 Challenge — Part 3 | 1,135 | May 3, 2022, 8:07 p.m. |
| The SZ42 Challenge — Part 2 | 1,134 | May 3, 2022, 1:25 a.m. |
| The SZ42 Challenge — Part 1 | 1,133 | May 3, 2022, 12:30 a.m. |
| Double Column Transposition — Part 2 | 1,088 | April 1, 2022, 10:08 p.m. |
| Alice's Birthday Party (Part 1) | 1,080 | March 30, 2022, 9:23 p.m. |
| Alberti Challenge — Part 1 | 125 | March 29, 2022, 11:42 p.m. |
| New Year's Greetings — Part 4 | 100 | March 12, 2022, 11:05 p.m. |
| New Year's Greetings — Part 3 | 100 | March 12, 2022, 9:11 p.m. |
| New Year's Greetings — Part 2 | 100 | March 12, 2022, 8:50 p.m. |
| New Year's Greetings — Part 1 | 100 | March 12, 2022, 8:36 p.m. |
| Recycled One-Time Pad | 100 | March 11, 2022, 1:51 a.m. |
| ADFGVX — Part 1 | 100 | Feb. 28, 2022, midnight |
| Letter to the Templars — Part 3 | 1,084 | Feb. 25, 2022, 1:31 a.m. |
| The Einstein Enigma | 1,106 | Feb. 24, 2022, 7:59 p.m. |
| Zodiac Cipher | 100 | Feb. 19, 2022, 6:44 a.m. |
| A hidden word — Part 2 | 100 | Feb. 17, 2022, 10:14 p.m. |
| Modular Sequences | 100 | Feb. 15, 2022, 9:03 p.m. |
| M-138 — Part 4 | 1,091 | Feb. 12, 2022, 2:03 a.m. |
| M-138 — Part 3 | 1,091 | Feb. 11, 2022, 9:46 p.m. |
| M-138 — Part 2 | 1,091 | Feb. 10, 2022, 1:14 a.m. |
| Number Sequence — Part 7 | 100 | Feb. 8, 2022, 8:13 p.m. |
| Number Sequence — Part 5 | 100 | Feb. 8, 2022, 7:46 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 100 | Jan. 31, 2022, 2:44 a.m. |
| Number Sequence — Part 10 | 100 | Dec. 16, 2021, 3:35 a.m. |
| The Last Note | 100 | Dec. 6, 2021, 3:02 a.m. |
| Multilingual Monoalphabetic Substitution | 100 | Dec. 5, 2021, 11:33 a.m. |
| Hill Cipher with Sudoku Key | 100 | Dec. 5, 2021, 10:31 a.m. |
| Playfair with hints about the grid | 100 | Dec. 4, 2021, 3:16 a.m. |
| Number Sequence — Part 9 | 100 | Dec. 4, 2021, 3:11 a.m. |
| Playfair Encryption | 100 | Dec. 3, 2021, 10:50 p.m. |
| Image Noise | 100 | Dec. 3, 2021, 10:44 p.m. |
| A Secret Message from Castle Mansfeld | 100 | Dec. 3, 2021, 10:14 p.m. |
| Autokey Cipher | 100 | Dec. 2, 2021, 10:35 a.m. |
| Molehunt (Part 2/3) | 100 | Dec. 2, 2021, 10:16 a.m. |
| The Book Code: A Challenge for Bookworms | 100 | Dec. 2, 2021, 9:43 a.m. |
| Number Sequence — Part 6 | 100 | Dec. 1, 2021, 6:43 p.m. |
| ¿No Hablas Español? No problemo! | 100 | Nov. 27, 2021, 8:12 a.m. |
| Molehunt (Part 1/3) | 100 | Nov. 27, 2021, 7:42 a.m. |
| Pigpen with a twist — Part 1 | 100 | Nov. 26, 2021, 9:31 p.m. |
| Cryptanalysis Hacking Puzzles — Part 2 | 100 | Nov. 26, 2021, 7:30 a.m. |
| Nils away on travel | 100 | Nov. 26, 2021, 7:23 a.m. |
| Classical Ciphers^3 | 100 | Nov. 25, 2021, 10:01 a.m. |
| Enigma Messages with Repeated Letters — Part 1 | 100 | Nov. 25, 2021, 9:58 a.m. |
| M-138 — Part 1 | 100 | Nov. 25, 2021, 5:11 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Nov. 24, 2021, 5:06 a.m. |
| Reserve Hand Procedure — Part 1 | 100 | Nov. 23, 2021, 11:19 p.m. |
| How do you become a big cryptographer? | 100 | Nov. 23, 2021, 4:34 a.m. |
| Modified Caesar Cipher | 100 | Nov. 23, 2021, 4:20 a.m. |
| From Russia with Love | 100 | Nov. 22, 2021, 9 p.m. |
| Snow White and the seven dwarfs | 100 | Nov. 22, 2021, 10:30 a.m. |
| One-Time Pad with Flaws | 100 | Nov. 22, 2021, 4:34 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Nov. 21, 2021, 10:04 p.m. |
| Number Sequence — Part 8 | 100 | Nov. 21, 2021, 5:08 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Nov. 21, 2021, 4:57 a.m. |
| Advent-Challenge — Part 1 | 100 | Nov. 21, 2021, 1:49 a.m. |
| Grille Cipher | 100 | Nov. 21, 2021, 1:39 a.m. |
| Factorization Cipher — Part 1 | 100 | Nov. 20, 2021, 10:59 p.m. |
| Monoalphabetic Substitution | 100 | Nov. 20, 2021, 12:34 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | Nov. 19, 2021, 10:51 p.m. |
| Number Sequence — Part 4 | 100 | Nov. 19, 2021, 10:30 p.m. |
| A hidden word | 100 | Nov. 19, 2021, 10:22 p.m. |
| Letter to the Templars — Part 2 | 100 | Nov. 19, 2021, 10:04 p.m. |
| Number Sequence — Part 3 | 100 | Nov. 19, 2021, 9:59 p.m. |
| Letter to the Templars — Part 1 | 100 | Nov. 19, 2021, 3:57 a.m. |
| Beaver Code | 100 | Nov. 19, 2021, 3:39 a.m. |
| Caesar Encryption | 100 | Nov. 19, 2021, 2:01 a.m. |
| Number Sequence — Part 2 | 100 | Nov. 18, 2021, 10:55 p.m. |
| Original Caesar Cipher | 100 | Nov. 18, 2021, 7:09 p.m. |
| Number Sequence | 100 | Nov. 18, 2021, 7:03 p.m. |
| Lightweight Introduction to Lattices — Part 1 | 100 | Nov. 18, 2021, 8:29 a.m. |
| Find the right route — Part 1 | 100 | Nov. 11, 2021, 2:56 a.m. |
| Wheatstone Cryptograph — Part 1 | 100 | Nov. 10, 2021, 5:05 a.m. |
Gold1
Silver0
Bronze0
