Collections of all CTF challenges made by me.
For some reasons, I have made several CTF Crypto challenges. Inspired by Septyem, who was again inspired by Law, I think it's worthwhile to write them down.
Some of the challenges may be quite trivial, while others are, to some extend, a little of challenging at time when I made it. Learning further, however, these seemingly difficult challenges were not that hard any more. Hope you had the same feeling as me and really learned something from solving these challenges. Meanwhile, I will try my best to make more novel as well as meaningful challenges and bring you new knowledge about Cryptography.
May this repo be of some help to you 🙃
| Name | Event | DIfficulty | Summary | Flag Source | Writeup |
|---|---|---|---|---|---|
| Keyboard | NCTF 2019 | easy | intuitive keyboard cipher | \ | link |
| Sore | NCTF 2019 | easy | vigenere cipher | \ | link |
| babyRSA | NCTF 2019 | easy | recover RSA modulus, given |
\ | link |
| childRSA | NCTF 2019 | easy | Pollard's p-1 method | \ | link |
| Reverse | NCTF 2019 | easy | recover other DES subkeys given only 1 subkey | \ | link |
| easyRSA | NCTF 2019 | medium | RSA decryption when |
\ | link |
| NHP | 高校战“疫”网络安全分享赛 | medium | DSA nonce bias attack | \ | link |
| GGH | GYCTF 2020 | medium | Nguyen's attack against GGH | \ | link |
| CRT | VN招新赛(2020年2月) | easy | multiple solutions of CRT | \ | link |
| Fast | VN招新赛(2020年2月) | easy | factor via calculating gcd | \ | link |
| Backtrace | VN招新赛(2020年2月) | easy | backtrace MT19937 | \ | link |
| Sum | WMCTF 2020 | medium | solving a 180-n subset-sum problem via BKZ | \ | link |
| babySum | WMCTF 2020 | easy | solving a 120-n subset-sum problem via BKZ | \ | link |
| Game | WMCTF 2020 | easy | the BEAST attack | The Catcher in the Rye | link |
| babyProof | N1CTF 2020 | easy | gain knowledge by solving HNP | \ | link |
| RRSA | NCTF 2020 | easy | Common Modulus Attack | The Legend of 1900 | link |
| RRRSA | NCTF 2020 | medium | Common Modulus Attack Plus | Gone with the wind | link |
| Oracle | NCTF 2020 | easy | Mini Bleichenbacher Attack | \ | link |
| Logon | 春秋杯春季赛 2021 | easy | A simple instance of the ZeroLogon attack | \ | link |
| n1ogin | N1CTF 2021 | easy | CBC padding oracle + Timing attack | \ | link |