RDRAND

RDRAND (for "read random"; known as Intel Secure Key Technology, codename Bull Mountain) is an instruction for returning random numbers from an Intel on-chip hardware random number generator which has been seeded by an on-chip entropy source. Intel introduced the feature around 2012, and AMD added support for the instruction in June 2015. (RDRAND is available in Ivy Bridge processors and is part of the Intel 64 and IA-32 instruction set architectures.)

The random number generator is compliant with security and cryptographic standards such as NIST SP 800-90A, FIPS 140-2, and ANSI X9.82. Intel also requested Cryptography Research Inc. to review the random number generator in 2012, which resulted in the paper Analysis of Intel's Ivy Bridge Digital Random Number Generator.

RDSEED is similar to RDRAND and provides lower-level access to the entropy-generating hardware. The RDSEED generator and processor instruction rdseed are available with Intel Broadwell CPUs and AMD Zen CPUs.