(I apologize for the crossposting; I feel that this is relevant to the newsgroups and mailing lists that I've posted this to) Hi, we're trying to design and build a hardware random number generator for use in key generation for secret key cryptosystems (likely to be at least a one time pad, perhaps DES or IDEA), as part of a hardware design project. We'll be putting the transmitter and receiver on expansion cards for ibm-compatible pc's, and hopefully be able to keep as much of the work as possible in hardware. My question is, I am trying to come up with ways of building this true RNG (random number generator) using a few simple components. For my noise source, I will probably be using thermal noise in electrical components. I understand that noise has a Gaussian distribution through time (i assume time referring to the time interval between successive signals of a certain power/amplitude?), and will be finding the median of this distribution so as to sample the random binary bits on either side of this median. We will attempt to design something which will automatically find the median in a given set of conditions. (I am told this is called anti-biasing?) My questions are: does anyone know of any actual implementations of this sort of RNG? can anyone suggest a good introductory reference to noise, random behaviour or sampling from random sources? what sort of hardware requirements do the DES, IDEA and RSA algorithms have? We will not be using IC's built for the DES or RSA encryption, but will perhaps program a controller of some sort to do this. I am afraid that RSA (for the initial secret key exchange) will take too long on an 8088 or lesser processor. we're looking for bitrates of about 1kbits/s from the RNG, since 75% of that will likely be thrown away in the process of 'pairwise (something)'. (if two consecutive bits are the same, throw them out, if they are different, take the first one) I would appreciate any comments, answers, concerns, &c Junya hojunya@ecf.toronto.edu