ANSI X9.82-3-2007 (R2017) consists of four parts:

• Part 1: Overview and Basic Principles
• Part 2: Entropy Sources
• Part 3: Deterministic Random Bit Generator Mechanisms
• Part 4: Random Bit Generator Construction

Part 1 should be read for a basic understanding of this Standard before reading Part 3. This part of ANSI X9.82 (Part 3) defines mechanisms for the generation of random bits using deterministic methods. The DRBG mechanisms are not sufficient by themselves to define a Random Bit Generator (RBG); Parts 2 and 4 of this Standard provide further requirements for the design of an RBG.

Part 3 includes:

• 1. A model for a deterministic random bit generator (DRBG),
• 2. Requirements for DRBG mechanisms,
• 3. Specifications for DRBG mechanisms that are based on hash functions or block ciphers, or are based on number theoretic problems,
• 4. Implementation issues, and
• 5. Assurance considerations.

A DRBG is based on a DRBG mechanism as specified in this part of the Standard and includes a source of entropy input. Part 3 specifies several diverse DRBG mechanisms, all of which provided acceptable security when this Standard was approved. However, in the event that new attacks are found on a particular class of mechanisms, a diversity of approved mechanisms will allow a timely transition to a different class of DRBG mechanism.

Random number generation does not require interoperability between two entities, e.g., communicating entities may use different DRBG mechanisms without affecting their ability to communicate. Therefore, an entity may choose a single appropriate DRBG mechanism for its applications; see Annex D for a discussion of DRBG selection.

The precise structure, design and development of a random bit generator is outside the scope of this Standard.