According to the Wikipedia entry for the Alternating Step pseudorandom number generator, there is no public cryptanalysis for this device since it was invented back in 1987 by C.G. Gunther. I have several questions about this:
- If it hasn't been cracked since 1987, why is it not considered to be a candidate for a "one way function" like the RSA crypto system, the discrete logarithm system, etc.?
- If it is unbreakable, why isn't everybody using it?
- Why doesn't Mr. Gunther have a U.S. patent for such a great invention?