Since they weren't mentioned in this thread, I'll point out that there are better sources of entropy than /dev/random, /dev/urandom, and the Windows API. For example, the two sites https://random.org/integers https://www.fourmilab.ch/hotbits/secure_generate.html both offer free random bits via a secure REST interface. Random.org is run by Mads Haahr of the School of Computer Science and Statistics at Trinity College, Dublin. They use background atmospheric radio noise to generate the entropy. Fourmilab is run by John Walker. He uses a source of radioactive decay (Ce 137) and a geiger counter to generate the entropy. Both sites have gone to some trouble in design and testing to ensure that their entropy is truly random. There are quotas on the number of bits you can retrieve per day for free at each of the sites. At random.org, you can purchase additional entropy at low cost. Regards, Yitz