CrossCTF_2017: Close Friends

Category: Cryptography Points: 20 Description:

Alice and Bob are very close friends. They share their secrets with each other and they do not want others to intercept it. So they decided to implement their own RSA to encrypt their messages. File here

Write-up

This is a Fermat's RSA attack challenge requiring us to use it's functions. Only doable in python

$ ./solve.py 
Flag: CrossCTF{its_g00d_t0_hav3_c1o5e_friend5_i5nt_it}

Therefore, the flag is CrossCTF{its_g00d_t0_hav3_c1o5e_friend5_i5nt_it}.