Good day: I happen to be very familiar with this subject, having developed, analyzed and qualified two different card-shuffling algorithms for real-money play in the online card game business. There is a fair bit of literature on this subject.
Some tips that I can share without breaking an NDA: 1) Do not use current time other than as an _adjunct_ to initial seeding of a quality PRNG. Under OpenBSD, you can obtain a good initial seed from /dev/?random, so why bother using time at all? 2) Use of a hardware device (HRNG), such as the SG-100 from Protego (Sweden) or motherboard HRNG is preferred to a PRNG, as its state cannot be observed in memory. 3) Qualify the quality of your random seed if it is coming from an HRNG. Some of these things have "warm-up time" and will initially produce poor entropy. 4) Do not use the % (modulo) operator to select a card. The residues from % introduce small amounts of bias, and this is a disqualifying factor for regulated gaming. 5) Knuth's "Art of Computer Programming" has an algorithm for fairly shuffling cards. Unfortunately it assumes perfect floating-point math, which a computer cannot really do. The algorithm, however, is worth studying. CHEERS -- Jack Bates Venice, CA, USA I play Texas Hold'Em at http://www.fulltiltpoker.com
