2023 Google CTF writeup
| Name | Category | Points | Solves |
|---|---|---|---|
| least common genominator | CRYPTO | 50 / 500 | 352 |
Someone used this program to send me an encrypted message but I can’t read it! It uses something called an LCG, do you know what it is? I dumped the first six consecutive values generated from it but what do I do with it?!
See attachments.
See solutions.
| Name | Category | Points | Solves |
|---|---|---|---|
| mytls | CRYPTO | 197 / 500 | 52 |
I implemented my own mTLS. It supports forward secrecy and it should be faster than yours!
nc mytls.2023.ctfcompetition.com 1337
See attachments.
See solutions.
| Name | Category | Points | Solves |
|---|---|---|---|
| cursved | CRYPTO | 237 / 500 | 36 |
This new signature scheme I built should be super secure. I know that you do not have a quantum computer, so what could possibly go wrong.
nc cursved.2023.ctfcompetition.com 1337
See attachments.
See solutions.
| Name | Category | Points | Solves |
|---|---|---|---|
| primes | CRYPTO | 228 / 500 | 39 |
I have prepared a flag for you but unfortunately it has been mangled somehow :/
See attachments.
See solutions.
| Name | Category | Points | Solves |
|---|---|---|---|
| mhk2 | CRYPTO | 308 / 500 | 18 |
I hid your flag using one of Murakami’s knapsacks
See attachments.
See solutions.
| Name | Category | Points | Solves |
|---|---|---|---|
| zip | CRYPTO | 406 / 500 | 6 |
Someone rolled their own implementation of PKZIP-compatible encryption to produce an encrypted ZIP file. The PKZIP-compatible cipher is old and known to be weak, but did the author leak sufficient information for you to decrypt the flag?
See attachments.
See solutions.
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