## TL;DRThe title made me come out of  smooth numbers. Maybe it can be cracked with Pollard's p − 1 algorithm?
\* or Williams' p + 1 algorithm according to P4's writeup. I'm not sure....
Then, with a quick Google "smooth CTF",  I find a [smooth writeup](https://github.com/BatmansKitchen/ctf-writeups/tree/master/2016-sharifctf). 
The tool [primefac](https://pypi.python.org/pypi/primefac) is able to factor N into p, q in a jiffy! Thus, we can decrypt the HTTPS traffic.
## Full writeup* In Wireshark, extract the server certificate. You may refer to [this](https://ctf.rip/bsides-sf-ctf-2017-root-crypto-challenge/)* `openssl x509 -inform DER -in certificate.der -text` to extract the *N* and *e*.* Factor *N* with `primefac` to *p*, *q** Run `./rsatool.py -n $n -p $p -q $q -e $e -v DER -o privkey.cert`. The rsatool can be found [here](https://github.com/ius/rsatool).* Follow this [tutorial](https://support.citrix.com/article/CTX116557) to decrypt the HTTPS in the pcap.* Get the flag: `SECCON{One of these primes is very smooth.}`