| Number Sequence — Part 7 | 100 | Oct. 29, 2015, 3:30 p.m. |
| Number Sequence — Part 6 | 100 | Oct. 29, 2015, 2:53 p.m. |
| Number Sequence — Part 8 | 102 | Oct. 29, 2015, 2:39 p.m. |
| A hidden word | 150 | Jan. 7, 2013, 8:13 p.m. |
| BCR code (Book-Caesar-RSA) | 1,255 | Nov. 22, 2012, 8:58 p.m. |
| Letter to the Templars — Part 3 | 1,298 | Nov. 21, 2012, 8:35 p.m. |
| Letter to the Templars — Part 2 | 101 | Nov. 21, 2012, 8:24 p.m. |
| Letter to the Templars — Part 1 | 101 | Nov. 21, 2012, 8:19 p.m. |
| Beaver Code | 101 | Nov. 21, 2012, 7:32 p.m. |
| Number Sequence — Part 5 | 100 | Nov. 21, 2012, 7:11 p.m. |
| How do you become a big cryptographer? | 101 | Nov. 21, 2012, 3:10 a.m. |
| Number Sequence — Part 4 | 100 | Nov. 20, 2012, 11:04 p.m. |
| Number Sequence — Part 3 | 125 | April 3, 2012, 8:48 p.m. |
| The Book Code: A Challenge for Bookworms | 200 | March 21, 2012, 10:23 p.m. |
| ECDH-Key Exchange for Beginners | 150 | Feb. 25, 2012, 12:13 a.m. |
| Partial Key Exposure with RSA — Part 1 | 2,000 | Feb. 11, 2012, 2:53 p.m. |
| Factorization Cipher — Part 3 | 1,824 | Jan. 8, 2012, 1:11 a.m. |
| Lunchtime Attack on the Fully Homomorphic Encryption Scheme | 1,159 | Dec. 30, 2011, 6:27 p.m. |
| Pigpen with a twist — Part 3 | 1,222 | Dec. 23, 2011, 3:45 p.m. |
| Monoalphabetic substitution with camouflage — Part 4 | 200 | Dec. 22, 2011, 11:32 a.m. |
| Lattice Part 1 | 1,169 | Dec. 22, 2011, 12:27 a.m. |
| Monoalphabetic Substitution | 100 | Dec. 16, 2011, 11:43 a.m. |
| RSA: Two different keys — same ciphertext | 1,217 | Dec. 16, 2011, midnight |
| Kaskade-S/T — Part 1 | 100 | Dec. 14, 2011, 3:52 p.m. |
| Monoalphabetic substitution with camouflage — Part 2 | 1,547 | Dec. 13, 2011, 9:43 p.m. |
| Unusual encryption using a diophantine equation | 1,229 | Dec. 13, 2011, 12:25 p.m. |
| Playfair Encryption | 100 | Dec. 13, 2011, 1:34 a.m. |
| Zodiac Cipher | 100 | Dec. 12, 2011, 11:39 p.m. |
| One-Time Pad with Flaws | 100 | Dec. 12, 2011, 12:09 a.m. |
| Broadcasting and low exponent — RSA Attack | 1,207 | Dec. 11, 2011, 8:56 p.m. |
| Alice's Birthday Party (Part 2) | 1,151 | Dec. 11, 2011, 8:36 p.m. |
| Alice's Birthday Party (Part 1) | 1,151 | Dec. 11, 2011, 8:04 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 2 | 100 | Dec. 11, 2011, 5:45 p.m. |
| A modified homophonic cipher with reduced alphabets — Part 1 | 100 | Dec. 11, 2011, 5:14 p.m. |
| Monoalphabetic substitution with camouflage — Part 3 | 1,660 | Dec. 10, 2011, 8:34 p.m. |
| Caesar Encryption | 100 | Dec. 10, 2011, 3:23 p.m. |
| Pigpen with a twist — Part 1 | 101 | Dec. 10, 2011, 2:49 p.m. |
| Grille Cipher | 102 | Dec. 9, 2011, 11:29 p.m. |
| Classical Ciphers^3 | 100 | Dec. 9, 2011, 10:58 p.m. |
| Not-so-Secret Message from Malawi — Part I (RSA) | 1,151 | Dec. 8, 2011, 1:36 a.m. |
| Affine Codes / Modulo Arithmetic with N / Extended Euclid | 101 | Dec. 7, 2011, 10:35 p.m. |
| Factorization Cipher — Part 2 | 1,547 | Dec. 7, 2011, 9:47 p.m. |
| Factorization Cipher — Part 1 | 102 | Dec. 6, 2011, 7:53 p.m. |
| Modified Caesar Cipher | 101 | Dec. 6, 2011, 1:05 p.m. |
| Post-Quantum Cryptography: Unbalanced Oil and Vinegar System — Part 1 | 100 | Dec. 5, 2011, 1:01 p.m. |
| Number Sequence — Part 2 | 101 | Dec. 4, 2011, 11:30 p.m. |
| Number Sequence | 100 | Dec. 4, 2011, 11:26 p.m. |
| Original Caesar Cipher | 100 | Dec. 4, 2011, 10:45 p.m. |
Gold0
Silver1
Bronze1
