1. A random number generator comprising: a computer having a parallel port, said parallel port including data and control lines; a random number generator circuit for producing a random sequence of signals, said random number generator circuit including power supply means for powering said circuit from power supplied by one or more of the data and control lines of said parallel port; and electrical connecting means for transferring power from said computer to said power supply means via said parallel port and for communicated signals generated by said random number generator circuit to said computer through said parallel port.