| Nils away on travel | 200 | Aug. 8, 2013, 7:19 p.m. |
| BCR code (Book-Caesar-RSA) | 1,216 | Jan. 15, 2013, 5:31 p.m. |
| A hidden word | 110 | Jan. 15, 2013, 3:09 p.m. |
| Smartcard RSA | 1,125 | Jan. 14, 2013, 7:40 p.m. |
| Factorization Cipher — Part 2 | 1,152 | Jan. 14, 2013, 4:02 p.m. |
| Letter to the Templars — Part 3 | 1,233 | Jan. 13, 2013, 8:35 p.m. |
| Letter to the Templars — Part 2 | 101 | Jan. 13, 2013, 8:25 p.m. |
| Number Sequence — Part 4 | 100 | Jan. 13, 2013, 8:07 p.m. |
| Beaver Code | 101 | Jan. 12, 2013, 8:02 p.m. |
| Letter to the Templars — Part 1 | 200 | July 17, 2012, 11:23 a.m. |
| Number Sequence — Part 3 | 200 | March 31, 2012, 7:28 p.m. |
| The Book Code: A Challenge for Bookworms | 200 | March 21, 2012, 11:36 p.m. |
| ECDH-Key Exchange for Beginners | 200 | Feb. 24, 2012, 3:06 p.m. |
| AES key — encoded in the machine readable zone of a European ePassport | 1,406 | Feb. 1, 2012, 7:17 p.m. |
| Factorization Cipher — Part 1 | 200 | Oct. 18, 2011, 3:28 a.m. |
| Grille Cipher | 150 | Oct. 15, 2011, 7:39 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 101 | Sept. 28, 2011, 12:33 p.m. |
| A really long number sequence | 1,398 | Sept. 23, 2011, 1:51 a.m. |
| Kaskade-S/T — Part 1 | 101 | Sept. 16, 2011, 11:43 p.m. |
| Enigma Part 1 | 1,162 | Sept. 9, 2011, 10:01 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 200 | Sept. 9, 2011, 12:24 p.m. |
| Pigpen with a twist — Part 1 | 200 | Sept. 5, 2011, 10:17 p.m. |
| Classical Ciphers^3 | 100 | Sept. 5, 2011, 5:21 p.m. |
| Modified Caesar Cipher | 200 | Sept. 2, 2011, 4:05 p.m. |
| Molehunt (Part 2/3) | 100 | Aug. 27, 2011, 11:52 a.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,165 | Aug. 21, 2011, 10:22 p.m. |
| Hybrid Encryption I | 1,168 | Aug. 21, 2011, 3:31 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,337 | Aug. 21, 2011, 12:48 p.m. |
| Alice's Birthday Party (Part 2) | 1,165 | Aug. 21, 2011, 12:45 p.m. |
| Alice's Birthday Party (Part 1) | 1,165 | Aug. 21, 2011, 3 a.m. |
| Number Sequence — Part 2 | 103 | Aug. 19, 2011, 2:42 p.m. |
| RSA: Two different keys — same ciphertext | 1,824 | Aug. 17, 2011, 4:29 p.m. |
| ADFGVX — Part 2 | 200 | Aug. 16, 2011, 11:32 a.m. |
| Letter from the Alleged Countess Julie von Ortenburg | 100 | Aug. 14, 2011, 2:15 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Aug. 14, 2011, 1:35 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Aug. 14, 2011, 12:43 a.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,166 | Aug. 13, 2011, 5:52 p.m. |
| Cracking SHA1-Hashed Passwords | 1,213 | Aug. 13, 2011, 4:56 p.m. |
| Monoalphabetic Substitution | 100 | Aug. 3, 2011, 5:01 p.m. |
| One-Time Pad with Flaws | 100 | Aug. 3, 2011, 4:31 p.m. |
| Caesar Encryption | 100 | Aug. 3, 2011, 2:08 p.m. |
| Original Caesar Cipher | 100 | Aug. 3, 2011, 1:45 p.m. |
| Number Sequence | 100 | Aug. 3, 2011, 1:44 p.m. |
Gold1
Silver1
Bronze0
