RSA

RSA is one of the most common modern cryptosystems, known for it's public and private key encryption. If you see public and private keys, there is a strong chance that it is an RSA problem, or at least RSA derived.

Read this: https://ctf101.org/cryptography/what-is-rsa/

Follow this writeup and submit your solution: https://qy.sg/x-ctf-fact0r!z3-and-fact0r!z3_aga!n-crypto/