US Patent 7293054 Random number source and associated methods

A random number source includes a ring oscillator generating an internal clock signal having random phase noise, and a first linear feedback shift register connected to the ring oscillator. A counter is connected to a first tap of the first linear feedback shift register for generating a count signal. A feedback bit controller is connected to a second tap of the first linear feedback shift register for generating a random feedback bit for a time based upon the count signal. A second linear feedback shift register is connected to the feedback bit controller for generating a random number based upon the random feedback bit.