| Spanish Strip Cipher — Part 1 | 1,613 | April 1, 2014, 12:18 a.m. |
| Enigma Messages with Repeated Letters — Part 4 | 200 | March 6, 2014, 12:57 p.m. |
| Enigma Messages with Repeated Letters — Part 3 | 200 | March 5, 2014, 7:28 p.m. |
| Enigma Messages with Repeated Letters — Part 5 | 200 | March 5, 2014, 5:39 p.m. |
| RSA Factoring Challenge: RSA-210 | 0 | Dec. 1, 2013, 10:53 p.m. |
| Enigma Messages with Repeated Letters — Part 2 | 120 | Nov. 2, 2013, 1:33 a.m. |
| Trifid Cipher | 150 | Oct. 30, 2013, 10 a.m. |
| Enigma Messages with Repeated Letters — Part 1 | 200 | Sept. 26, 2013, 3:57 p.m. |
| Hill Cipher with Sudoku Key | 113 | Sept. 12, 2013, 3:45 p.m. |
| From Russia with Love | 200 | Sept. 4, 2013, 4:39 p.m. |
| Nils away on travel | 200 | Aug. 8, 2013, 2:10 p.m. |
| RSA Factoring Challenge: RSA-704 | 0 | Aug. 1, 2013, 12:19 a.m. |
| ORYX Stream Cipher — Part 3 (revised) | 2,000 | June 6, 2013, 11:37 p.m. |
| Notes of an Italian Soldier | 800 | May 19, 2013, 1:45 p.m. |
| Cascading Encryption — Part 3/3 | 1,353 | April 23, 2013, 9:11 p.m. |
| Cascading Encryption — Part 2/3 | 1,349 | April 21, 2013, 3:29 p.m. |
| Snow White and the seven dwarfs | 200 | April 20, 2013, 1:54 p.m. |
| Typex — Part 2 | 2,000 | April 4, 2013, 12:08 a.m. |
| Reserve Hand Procedure — Part 1 | 200 | March 6, 2013, 10:50 p.m. |
| Typex — Part 1 | 1,613 | March 4, 2013, 3:08 p.m. |
| Multilingual Monoalphabetic Substitution | 106 | Feb. 16, 2013, 12:48 a.m. |
| Cascading Encryption — Part 1/3 | 200 | Jan. 26, 2013, 2:06 a.m. |
| Enigma Messages | 200 | Jan. 23, 2013, 11:06 p.m. |
| Playfair with hints about the grid | 200 | Jan. 16, 2013, 5:50 p.m. |
| A hidden word | 200 | Jan. 6, 2013, 10:09 p.m. |
| Strange Message from Thessaloniki | 150 | Dec. 11, 2012, 11:06 p.m. |
| Recycled One-Time Pad | 111 | Nov. 28, 2012, 11:42 p.m. |
| Letter to the Templars — Part 3 | 2,000 | Oct. 9, 2012, 3:34 p.m. |
| BCR code (Book-Caesar-RSA) | 2,000 | Sept. 13, 2012, 3:36 p.m. |
| Beaver Code | 200 | Aug. 13, 2012, 8:54 p.m. |
| Letter to the Templars — Part 2 | 200 | July 30, 2012, 8:51 p.m. |
| Letter to the Templars — Part 1 | 200 | July 16, 2012, 10:58 p.m. |
| An 'unhearable' message | 125 | June 9, 2012, 3:45 p.m. |
| How do you become a big cryptographer? | 200 | May 28, 2012, 11:26 p.m. |
| Keyshanc — Part 2 | 2,000 | May 22, 2012, 12:37 a.m. |
| Keyshanc — Part 1 | 2,000 | May 21, 2012, 11:06 p.m. |
| Concealed Messages — Vigenère's Night Sky | 1,613 | May 13, 2012, 1 p.m. |
| Number Sequence — Part 5 | 114 | April 24, 2012, 8:44 p.m. |
| Number Sequence — Part 4 | 114 | April 24, 2012, 8:43 p.m. |
| ¿No Hablas Español? No problemo! | 200 | April 19, 2012, 3:46 p.m. |
| Number Sequence — Part 3 | 200 | March 30, 2012, 11:43 p.m. |
| The Book Code: A Challenge for Bookworms | 200 | March 21, 2012, 10:28 p.m. |
| Monoalphabetic Substitution with Camouflage — Part 5 | 2,000 | March 10, 2012, 6:57 p.m. |
| ECDH-Key Exchange for Beginners | 200 | Feb. 24, 2012, 1:48 p.m. |
| Partial Key Exposure with RSA — Part 1 | 2,000 | Feb. 11, 2012, 1:58 p.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,725 | Jan. 19, 2012, 4:01 p.m. |
| Factorization Cipher — Part 3 | 1,725 | Jan. 8, 2012, 6:07 p.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 150 | Dec. 22, 2011, 6:04 p.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,824 | Dec. 9, 2011, 2:46 a.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,824 | Dec. 9, 2011, 12:14 a.m. |
| Factorization Cipher — Part 2 | 2,000 | Dec. 2, 2011, 2:05 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 2 | 1,182 | Nov. 19, 2011, 3:39 p.m. |
| Purple 1 | 1,155 | Nov. 14, 2011, 7:57 a.m. |
| Ku Klux Klan | 1,000 | Nov. 13, 2011, 7:02 p.m. |
| Monoalphabetic substitution with camouflage — Part 1 | 113 | Nov. 3, 2011, 7:31 p.m. |
| Unconcealed RSA messages | 2,000 | Nov. 3, 2011, 1:58 a.m. |
| Turing Bombe Enigma I | 200 | Oct. 18, 2011, 3:36 p.m. |
| An Invisible Message | 200 | Oct. 18, 2011, 3:35 p.m. |
| Factorization Cipher — Part 1 | 200 | Oct. 18, 2011, 1:56 a.m. |
| Grille Cipher | 200 | Oct. 14, 2011, 8:53 p.m. |
| Double Columnar Transposition | 200 | Oct. 12, 2011, 10:10 p.m. |
| Sigaba Part 1 | 1,159 | Oct. 2, 2011, 7:55 p.m. |
| Pigpen with a twist — Part 2 | 1,344 | Sept. 29, 2011, 8:07 p.m. |
| Zodiac Cipher | 100 | Sept. 21, 2011, 12:08 a.m. |
| Number Sequence — Part 2 | 101 | Sept. 21, 2011, 12:07 a.m. |
| Number Sequence | 100 | Sept. 21, 2011, 12:06 a.m. |
| Modified Caesar Cipher | 105 | Sept. 21, 2011, 12:04 a.m. |
| Original Caesar Cipher | 100 | Sept. 21, 2011, 12:03 a.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 101 | Sept. 21, 2011, 12:02 a.m. |
| One-Time Pad with Flaws | 100 | Sept. 20, 2011, 11:59 p.m. |
| Monoalphabetic Substitution | 100 | Sept. 20, 2011, 11:36 p.m. |
| Classical Ciphers^3 | 100 | Sept. 20, 2011, 11:35 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Sept. 20, 2011, 11:34 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Sept. 20, 2011, 11:33 p.m. |
| A Secret Message from Castle Mansfeld | 100 | Sept. 20, 2011, 11:31 p.m. |
| Playfair Encryption | 100 | Sept. 20, 2011, 11:12 p.m. |
| Caesar Encryption | 100 | Sept. 20, 2011, 11:02 p.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Sept. 20, 2011, 10:24 p.m. |
| Enigma Combinatorics | 100 | Sept. 20, 2011, 10:22 p.m. |
| Pigpen with a twist — Part 1 | 120 | Sept. 10, 2011, 7:56 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 200 | Sept. 9, 2011, 6:20 p.m. |
| Unusual encryption using a diophantine equation | 1,547 | Sept. 8, 2011, 5:22 p.m. |
| Pigpen with a twist — Part 3 | 1,576 | Sept. 8, 2011, midnight |
| A really long number sequence | 1,824 | Sept. 6, 2011, 11:40 p.m. |
| ADFGVX — Part 2 | 150 | Aug. 16, 2011, 5:56 p.m. |
| ADFGVX — Part 1 | 150 | Aug. 16, 2011, 5:15 p.m. |
| RSA: Two different keys — same ciphertext | 2,000 | Aug. 15, 2011, 9:52 p.m. |
| Music Code — Part 2 | 1,238 | Aug. 15, 2011, 1:27 p.m. |
| Music Code — Part 1 | 101 | Aug. 14, 2011, 4:51 p.m. |
| Akelarre Part 1 | 1,174 | Aug. 10, 2011, 11:47 p.m. |
| CMEA 2 | 14,472 | Aug. 7, 2011, 11:09 a.m. |
| Smartcard RSA | 1,169 | Aug. 3, 2011, 8:41 p.m. |
| ORYX Stream Cipher Part II | 1,168 | Aug. 3, 2011, 7:17 p.m. |
| ORYX Stream Cipher Part I | 1,168 | Aug. 3, 2011, 6:40 p.m. |
| CMEA 1 | 1,179 | July 29, 2011, 1:13 p.m. |
| Kaskade-S/T — Part 5 | 1,247 | July 23, 2011, 7:19 p.m. |
| Broadcasting and low exponent — RSA Attack | 2,000 | July 22, 2011, 9:37 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,170 | July 20, 2011, 5:48 p.m. |
| Kaskade-S/T — Part 3 | 1,216 | July 6, 2011, 1:33 a.m. |
| Kaskade-S/T — Part 2 | 1,217 | July 3, 2011, 11:15 p.m. |
| Kaskade-S/T — Part 1 | 101 | July 3, 2011, 11:37 a.m. |
| Molehunt (Part 3/3) | 1,175 | July 2, 2011, 10:09 p.m. |
| Molehunt (Part 1/3) | 100 | July 2, 2011, 9:14 p.m. |
| Molehunt (Part 2/3) | 100 | July 2, 2011, 8:41 p.m. |
| Enigma Part 2 | 1,174 | June 29, 2011, 11:51 p.m. |
| Lattice Part 1 | 1,236 | June 11, 2011, 5:16 p.m. |
| Cracking SHA1-Hashed Passwords | 1,260 | June 11, 2011, 12:08 a.m. |
| Enigma Part 1 | 1,178 | June 10, 2011, 7:25 p.m. |
| Hybrid Encryption I | 1,183 | June 7, 2011, 6:23 p.m. |
| RSA with Special d | 14,494 | June 7, 2011, 5:43 p.m. |
| Not-so-Secret Message from Malawi — Part II (ECC) | 1,179 | June 7, 2011, 12:19 a.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,179 | June 5, 2011, 11:39 p.m. |
| Alice's Birthday Party (Part 1) | 1,180 | June 2, 2011, 7:10 p.m. |
| Alice's Birthday Party (Part 2) | 1,180 | June 2, 2011, 6:56 p.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,213 | May 23, 2011, 9:53 p.m. |
Gold5
Silver16
Bronze22
