TLDR;
- RSA encryption/decryption oracle
- The oracle gives the flag ciphertext and the public modulus
- Just ask for the decryption of `c+n` where `c` is the flag ciphertext and `n` is the public modulus
- Note: The server expects and sends all values as bytes with little endian ordering

[writeup](https://jsur.in/posts/2020-04-13-dawgctf-2020-writeups#cha-cha-real-smooth)

Original writeup (https://jsur.in/posts/2020-04-13-dawgctf-2020-writeups#cha-cha-real-smooth).