Professor Chothia's research involves the development of new mathematical analysis techniques, and the application of these techniques to real world cyber security problems. He has many tier 1 cyber security publications, and has spoken at industry cyber security events, such as BlackHat, and hacker conferences, such as DEFCON, on work including payment security, transport ticketing, firmware analysis and formal protocol analysis. His team's rail work includes a detailed cryptographic analysis of the EuroRadio protocol, the protocols used in Positive Train Control and a proposal for a post quantum secure key management scheme for ERTMS. Professor Chothia has carried out rail cyber security projects for NCSC, the UN and the Office of Rail and Road.