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Recommendation for Random Bit Generator Constructions: NIST Publishes SP 800-90C

NIST has released SP 800-90C, the final document in the SP 800-90 series, which supports the generation of high-quality random bits for cryptographic and non-cryptographic use.

NIST has released Special Publication (SP) 800-90C, Recommendation for Random Bit Generator (RBG) Constructions. It is the final document in the SP 800-90 series, which supports the generation of high-quality random bits for cryptographic and non-cryptographic use.

SP 800-90C specifies constructions for implementing random bit generators (RBGs) that include deterministic random bit generator (DRBG) mechanisms as specified in SP 800-90A and use entropy sources as specified in SP 800-90B.

SP 800-90C includes constructions for four classes of RBGs:

  1. An RBG1 construction provides random bits from a device that is initialized from an external RBG.
  2. An RBG2 construction includes an entropy source that is available on demand.
  3. An RBG3 construction includes an entropy source that is continuously accessed to provide output with full entropy.
  4. An RBGC construction allows the use of a chain of RBGs that consists of only RBGC constructions on the same computing platform.
    Released September 25, 2025
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