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Search Search CSRC MENU Search Search Projects Publications Expand or Collapse Drafts for Public Comment All Public Drafts Final Pubs FIPS (standards) Special Publications (SP s ) IR (interagency/internal reports) CSWP (cybersecurity white papers) ITL Bulletins Project Descriptions Journal Articles Conference Papers Books Topics Expand or Collapse Security & Privacy Applications Technologies Sectors Laws & Regulations Activities & Products News & Updates Events Glossary About CSRC Expand or Collapse Computer Security Division Cryptographic Technology Software Security Group Hardware Security Group Security Engineering and Risk Management Applied Cybersecurity Division Cybersecurity and Privacy Applications National Cybersecurity Center of Excellence (NCCoE) National Initiative for Cybersecurity Education (NICE) Contact Us Information Technology Laboratory Computer Security Resource Center Publications NIST SP 800-90C Recommendation for Random Bit Generator (RBG) Constructions Share to Facebook Share to X Share to LinkedIn Share ia Email Documentation Topics Date Published: September 2025 Author(s) Elaine Barker (NIST) , John Kelsey (NIST) , Kerry McKay (NIST) , Allen Roginsky (NIST) , Meltem Sönmez Turan (NIST) Abstract The NIST Special Publication (SP) 800-90 series of documents supports the generation of high-quality random bits for cryptographic and non-cryptographic use. SP 800-90A, Recommendation for Random Number Generation Using Deterministic Random Bit Generators , specifies several deterministic random bit generator (DRBG) mechanisms based on cryptographic algorithms. SP 800-90B, Recommendation for the Entropy Sources Used for Random Bit Generation , provides guidelines for the development and validation of entropy sources. This document (SP 800-90C) specifies constructions for the implementation of random bit generators (RBGs) that include DRBG mechanisms as specified in SP 800-90A and that use entropy sources as specified in SP 800-90B. Constructions for four classes of RBGs — namely, RBG1, RBG2, RBG3, and RBGC — are specified in this document. The NIST Special Publication (SP) 800-90 series of documents supports the generation of high-quality random bits for cryptographic and non-cryptographic use. SP 800-90A, Recommendation for Random Number Generation Using Deterministic Random Bit Generators, specifies several deterministic random bit... See full abstract The NIST Special Publication (SP) 800-90 series of documents supports the generation of high-quality random bits for cryptographic and non-cryptographic use. SP 800-90A, Recommendation for Random Number Generation Using Deterministic Random Bit Generators , specifies several deterministic random bit generator (DRBG) mechanisms based on cryptographic algorithms. SP 800-90B, Recommendation for the Entropy Sources Used for Random Bit Generation , provides guidelines for the development and validation of entropy sources. This document (SP 800-90C) specifies constructions for the implementation of random bit generators (RBGs) that include DRBG mechanisms as specified in SP 800-90A and that use entropy sources as specified in SP 800-90B. Constructions for four classes of RBGs — namely, RBG1, RBG2, RBG3, and RBGC — are specified in this document. Hide full abstract Keywords deterministic random bit generator (DRBG) ; entropy ; entropy source ; random bit generator (RBG) ; randomness source ; RBG1 construction ; RBG2 construction ; RBG3 construction ; RBGC construction ; subordinate DRBG (sub-DRBG) Control Families None selected Documentation Publication: https://doi.org/10.6028/NIST.SP.800-90C Download URL Supplemental Material: RBG project Publication Parts: SP 800-90A Rev. 1 SP 800-90B Document History: 09/05/12: SP 800-90C (Draft) 04/13/16: SP 800-90C (Draft) 09/07/22: SP 800-90C (Draft) 07/03/24: SP 800-90C (Draft) 09/25/25: SP 800-90C (Final) Topics Security and Privacy random number generation HEADQUARTERS 100 Bureau Drive Gaithersburg, MD 20899 X (link is external) facebook (link is external) linkedin (link is external) instagram (link is external) youtube (link is external) rss govdelivery (link is external) Want updates about CSRC and our publications? 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