**Full write-up:** https://www.sebven.com/ctf/2021/08/23/corCTF2021-4096.html
Cryptography – 360 pts (219 solves) – Chall author: qopruzjf
Having many bits in your RSA modulus sounds great, but its security is defined by its generation. And let me tell you, using a load of small primes is not the way too go! The modulus can easily be factored and hence the ciphertext decrypted.