Data encryption and signal scrambling using programmable data conversion arrays

Abstract

A scrambling or encryption method involves analog-to-digital, digital-to-analog, analog-to-analog or digital-to-digital conversions that are constructed from one or more analog-to-digital or digital-to-analog conversions. For example, encryption of an analog signal converts the analog signal to an intermediate digital signal that is converted back into a scrambled analog signal. Encryption of a digital signal converts the digital signal to an intermediate analog signal that is converted back into an encrypted digital signal. The conversions between analog form and digital form and back can be repeated. A codec scrambling/descrambling and encryption/decryption implements one or more different analog-to-digital conversions and one or more digital-to-analog conversions. One embodiment of the codec includes a programmable conversion array that includes an array of transistors such as floating gate transistors in memory cells. Input circuitry applies an analog signal to gates of the transistors during an analog-to-digital conversion, and an encoder that generates an output digital value according to which transistor or transistors conduct while the analog signal is applied. For digital-to-analog conversion, a read circuit reads the threshold voltage of a transistor identified by a selected digital value to generate an analog voltage that is corresponds to the selected digital value. A selection circuit for the converter can route the digital output signal from the encoder to select a transistor to be read and route the analog output signal from the read circuit to the input circuitry. Accordingly, output values can be routed through the converter multiple times.