US Patent 10318462 Secure crypto module including optical glass security layer

An optical electromagnetic radiation (EM) emitter and receiver are located upon a printed circuit board (PCB) glass security layer. A predetermined reference flux or interference pattern, respectively, is an expected flux or reflection pattern of EM emitted from the EM emitter, transmitted by the glass security layer, and received by the EM receiver. When the PCB is subject to an unauthorized access thereof the optical EM transmitted by glass security layer is altered. An optical monitoring device that monitors the flux or interference pattern of the optical EM received by the EM receiver detects a change in flux or interference pattern, in relation to the reference flux or reference interference pattern, respectively, and passes a tamper signal to one or more computer system devices to respond to the unauthorized access. For example, one or more cryptographic adapter card or computer system functions or secured crypto components may be disabled.