INTRO (9) NetBSD Kernel Developer's Manual INTRO (9) NAME ...

RND (9) NetBSD Kernel Developer’s Manual RND (9)actually serviced by the interrupt handler, since on some systems interrupts can be shared.This function loses nearly all usefulness if it is called from a scheduled software interrupt. If thatis the only way to add the device as an entropy source, don’t.If it is desired to mix in the datum and to add in a timestamp, but not to actually estimate entropyfrom a source of randomness, passing NULL for rnd_source is permitted, and the device does notneed to be attached.rnd_add_data(rndsource_element_t ∗rnd_source , void ∗data , uint32_t len ,uint32_t entropy)adds (hopefully) random data to the entropy pool. len is the number of bytes in data andentropy is an "entropy quality" measurement. If every bit of data is known to be random,entropy is the number of bits in data.Timing information is also used to add entropy into the system, using inter-event timings.If it is desired to mix in the data and to add in a timestamp, but not to actually estimate entropyfrom a source of randomness, passing NULL for rnd_source is permitted, and the device does notneed to be attached.FILESThese functions are declared in src/sys/sys/rnd.h and defined in src/sys/dev/rnd.c.SEE ALSOrnd(4), rndctl(8)HISTORYThe random device was introduced in NetBSD 1.3.AUTHORSThis implementation was written by Michael Graff using ideas and algorithms gatheredfrom many sources, including the driver written by Ted Ts’o.BUGSThe only good sources of randomness are quantum mechanical, and most computers avidly avoid having truesources of randomness included. Don’t expect to surpass "pretty good".NetBSD 3.0 October 20, 1997 2