Linux Kernel Development, Second Edition

Appendix B. Kernel Random Number Generator

The Linux kernel implements a strong random number generator that is theoretically capable of generating true random numbers. The random number generator gathers environmental noise from device drivers into an entropy pool. This pool is accessible from both user processes and the kernel as a source of data that is not only random but also non-deterministic to an outside attacker. Such numbers are of use in various applications, most notably cryptography.

True random numbers differ from the pseudo-random numbers generated by functions such as those found in the C library. Pseudo-random numbers are created by a deterministic function. Although the function may generate a sequence of numbers that exhibit ...