Abstract:
Good randomness is a complex but necessary prerequisite in practical modern cryptography. However, missing that randomness can result in critical vulnerabilities. This thesis analyzes the vulnerabilities of repeated and factorable RSA keys in TLS. Using an up-to-date set of certificates from an internet-wide scan on 39 different ports, we searched for factorable and repeated keys using the methodology of Heninger et al. [14]. As a result, 1530 hosts were found to serve factorable keys (0.0042% of hosts) and 115,565 hosts (0.3133%) were found to serve repeated keys. Subsequently, we performed further analysis to identify device models serving factorable or repeated keys since their key generation algorithms are likely vulnerable.