| Advent-Challenge — Part 1 | 101 | June 14, 2018, 11:40 p.m. |
| Number Sequence — Part 8 | 100 | June 14, 2018, 11:31 p.m. |
| Heartbleed — Part 3 | 1,725 | Aug. 30, 2014, 6:20 p.m. |
| Heartbleed — Part 2 | 150 | Aug. 30, 2014, 12:03 a.m. |
| Heartbleed — Part 1 | 150 | Aug. 29, 2014, 11:35 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,111 | March 30, 2014, 8:10 p.m. |
| Brute-Force-Attack on Triple-DES with Reduced Key Space | 1,111 | March 29, 2014, 9:57 p.m. |
| Spanish Strip Cipher — Part 2 | 1,824 | March 29, 2014, 2:02 p.m. |
| Trifid Cipher | 101 | March 24, 2014, 7:29 p.m. |
| Hill Cipher with Sudoku Key | 200 | Sept. 5, 2013, 12:18 a.m. |
| From Russia with Love | 200 | Sept. 4, 2013, 11:40 p.m. |
| Broadcasting and low exponent — RSA Attack | 1,128 | Aug. 22, 2013, 12:30 p.m. |
| Hybrid Encryption I | 1,117 | Aug. 22, 2013, 1:51 a.m. |
| Alice's Birthday Party (Part 2) | 1,117 | Aug. 17, 2013, 1:43 a.m. |
| Snow White and the seven dwarfs | 101 | Aug. 16, 2013, 11:08 p.m. |
| Alice's Birthday Party (Part 1) | 1,117 | Aug. 15, 2013, 9:42 p.m. |
| RSA Factoring Challenge: RSA-704 | 0 | Aug. 15, 2013, 10:34 a.m. |
| A really long number sequence | 1,130 | Aug. 15, 2013, 10:23 a.m. |
| Nils away on travel | 125 | Aug. 12, 2013, 1:38 a.m. |
| Factorization Cipher — Part 2 | 1,145 | April 4, 2013, 5:35 a.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | March 30, 2013, 2:58 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | March 30, 2013, 2:05 a.m. |
| Zodiac Cipher | 100 | March 30, 2013, 1:25 a.m. |
| ¿No Hablas Español? No problemo! | 100 | March 29, 2013, 10:21 p.m. |
| Beaver Code | 100 | March 16, 2013, 1:44 p.m. |
| Reserve Hand Procedure — Part 1 | 110 | March 16, 2013, 2:25 a.m. |
| A hidden word | 108 | Jan. 18, 2013, 11:50 a.m. |
| Letter to the Templars — Part 3 | 1,660 | Oct. 13, 2012, 1:08 p.m. |
| Letter to the Templars — Part 2 | 200 | July 31, 2012, 4:28 p.m. |
| Factorization Cipher — Part 1 | 100 | July 31, 2012, 4:11 p.m. |
| Cracking SHA1-Hashed Passwords | 1,145 | July 29, 2012, 11:26 p.m. |
| Letter to the Templars — Part 1 | 108 | July 29, 2012, 8:41 p.m. |
| One-Time Pad with Flaws | 100 | July 14, 2012, 2:04 p.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 100 | July 13, 2012, 10:17 a.m. |
| Grille Cipher | 100 | June 22, 2012, 1:12 p.m. |
| Number Sequence — Part 4 | 102 | June 18, 2012, 8:05 p.m. |
| Number Sequence — Part 3 | 101 | June 18, 2012, 5:39 p.m. |
| Monoalphabetic Substitution | 100 | June 18, 2012, 5:02 p.m. |
| Number Sequence — Part 2 | 100 | June 18, 2012, 3:38 p.m. |
| Caesar Encryption | 100 | June 18, 2012, 3:36 p.m. |
| Original Caesar Cipher | 100 | June 18, 2012, 2:37 p.m. |
| Number Sequence | 100 | June 18, 2012, 2:29 p.m. |