solution

st98 uses NetworkMiner to retrieve the public key. I use primefac to factorize the key and Wireshark to read the flag. The factored primes are below.

11807485231629132025602991324007150366908229752508016230400000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001
12684117323636134264468162714319298445454220244413621344524758865071052169170753552224766744798369054498758364258656141800253652826603727552918575175830897