1. Field of the Invention
The invention relates to the field of random number generators.
2. Prior Art
Circuits for generating random numbers, or more accurately, pseudo random numbers are well-known in the art. One such circuit using a slow oscillator and fast oscillator is disclosed in U.S. Pat. No. 4,694,412. Other pseudo random number generators are described in U.S. Pat. Nos. 5,007,087 and 4,855,690. Systems for scrambling bits are also known such as shown in U.S. Pat. No. 4,791,594.
In "An LSI Random Number Generator (RNG)", published in Proc. Advances in Cryptology Conference on CRYPTO, 1984 by Fairfield, Mortenson and Coulthart, a slow and a fast oscillator are used where the natural variation in frequency of the slow oscillator is relied upon for developing the random signal. As will be seen the present invention improves upon this circuit.