Led a small research team that reverse-engineered and cracked the cryptographic security of Boston’s MBTA “T” fare collection system: magnetic and RFID cards. We built custom tooling end-to-end (Bitstir for magnetic-media forensics, a GNU Radio/USRP pipeline for RFID protocol capture, and an GPU-based brute-force framework) and demonstrated exploits that enabled arbitrary stored-value card creation and cloning. When our Professor Ron Rivest (inventor of MD5 hash, founder of RSA security) reached out to MBTA, they decided to call the FBI and file a federal lawsuit against us. We won, and set important precedent against overreach of the CFAA.