You can try to sign messages and send them to the ip:port. Sign the right message and you\'ll get the flag! Only problem---you don\'t have the signing key. I will give you this, though: sigs.txt is a file containing a bunch of signatures. I hope it helps. (P.S. Don\'t try and send the exact signatures in that file---that\'s cheating!)

Sources of the server and file with signatures are given.