Non-deterministic Random Bit Generator (NRBG)

March 4, 2025

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cyber risk assessment insurance cybersecurity best practices define rmm authentication TPRM ecosystem flaw hypothesis methodology high assurance guard 3rd party third-party CISOWhat’s an NRBG?

A Non-deterministic Random Bit Generator (NRBG) creates random numbers in specific ways.

Definition

An RBG that (when working properly) produces outputs that have full entropy. Contrast with a DRBG. Other names for nondeterministic RBGs are True Random Number (or Bit) Generators and, simply, Random Number (or Bit) Generators.
SOURCE: SP 800-90A

Used In a Sentence

You’re not going to get anywhere, Todd, if you keep using a broken NRBG to generate the numbers we require, c’mon now. How will we ever assess the third party cyber risk of anything without a functional NRBG?

More from NIST

NIST’s Randomness Beacon

NIST is implementing a source of public randomness–the NIST Randomness Beacon. The service (at https://beacon.nist.gov/home) uses two independent commercially available sources of randomness, each with an independent hardware entropy source and SP 800-90-approved components.

The Beacon is designed to provide unpredictability, autonomy, and consistency. Unpredictability means that users cannot algorithmically predict bits before they are made available by the source. Autonomy means that the source is resistant to attempts by outside parties to alter the distribution of the random bits. Consistency means that a set of users can access the source in such a way that they are confident they all receive the same random string.

Additional Random Number Generation Standards Development Bodies

Implementation-related References