Write-up of Hack.lu 2015’s Creative Cheating challenge.
The first challenge I solved on Hack.lu 2015, hosted by FluxFingers, was Creative Cheating.
Mr. Miller suspects that some of his students are cheating in an automated computer test. He captured some traffic between crypto nerds Alice and Bob. It looks mostly like garbage but maybe you can figure something out. He knows that Alice’s RSA key is (n, e) = (0x53a121a11e36d7a84dde3f5d73cf, 0x10001) (192.168.0.13) and Bob’s is (n, e) = (0x99122e61dc7bede74711185598c7, 0x10001) (192.168.0.37)
Upon inspection of the packet capture, we notice every packet from Alice (192.168.0.13) to Bob (192.168.0.37) contains a base64-encoded payload. E.g.