Portable, customizable electronic device, namely, a handheld security testing device with onboard computer software development tools, open-source firmware, and an operating system reminiscent of a computer game, for use in interacting with and testing the security of other electronic devices by spoofing two-factor authentication, emitting and receiving infrared signals, storing access-control credentials, transmitting and receiving wireless signals, and scanning, analyzing and penetration-testing radio protocols, computer interfaces, USB ports, and computer hardware; computer hardware for detecting and identifying access to computer networks and resources, performing vulnerability scans, and penetration testing; all of the foregoing for use by IT security professionals, computer hardware and software engineers, and electronics hobbyists for testing the security of computers and computer networks, for learning electronics and software engineering, and for prototyping electronics and software