# This is the UTCTF 2021 write up

## Small P Problem

I just write two interesting challenge that meaningful to me.

- The question require the share secret.
- The first steps we would need the secret key of A.
- We could use python to brute force the secret key of A.
- This is the small problem python that brute force and solve the challenge.
- The formula:
**A=(g**a)%p** where a is the secret key. Since it is hard to solve a with mathematic solution, we use brute force method.
- Then, we use formula
**sharesecret=((B**a)%p)**
- The flag is
**utflag{53919}**.

## Peeb Poob

This one is kinda fun.

- We open with Ghidra.
- Let look at encode();
- Let write the exact code in C programming. Source is here.
- Let reverse write the process in C programming. Look at the reverse process. It is reverse process.Source is here.
- We run it and get the flag! Have fun with this challenge
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- The flag is
**utflag{b33p_b00p_p33b_p00b}**.

Hope you guys enjoy this write up. Thanks to UTCTF for held this challenge.