Tags: factoring rsa-crypto rsa
Rating: 4.0
In this challenge, you connect to a server and can ask for RSA keys to be generated along with encrypted copies of the flag. The primes used in the keys are generated in a way that causes them to only have a small number of bits set to 1.
The public mudulus can be factored by exploiting this property in combination with a Hensel lift. Details in the writeup.
