Using unpredictable information to minimize leakage from smartcards and other cryptosystems

摘要

Methods and apparatuses for securing cryptosystems against external monitoring attacks reduce the amount (and signal to noise ratio) of useful information leaked during processing. This is generally accomplished by incorporating unpredictable information (100, 200) into the cryptographic processing. An embodiment of the invention use clock skipping in which a clock decorrelator (240) coupled to a source of unpredictable information generates a second clock signal (260) from a first clock signal (220) using the unpredictable information, such that the second clock signal cannot be reliably predicted from the first clock signal; The techniques may be implemented in hardware or software, may use a combination of digital and analog techniques, and may be deployed in a variety of cryptographic devices.