HmacDrbg

Source: hash.ts:153

HMAC-SHA256 Deterministic Random Bit Generator. Implements the formal NIST SP 800-90A Rev.1 HMAC_DRBG specification.

Properties:

• Cryptographically secure (HMAC-SHA256 as PRF)
• Domain-separated via the context string (prevents cross-use of the same seed for different purposes, e.g. "earnmore:pan" vs "earnmore:expiry")
• Rejection-sampled outputs eliminate modular bias (FIPS 186-5 §B.4.2)

• See:
  • - NIST SP 800-90A Rev.1 — HMAC_DRBG (formal standard) - FIPS 186-5 §B.4.2 — Rejection sampling for unbiased output

Constructors

new HmacDrbg(seed: Buffer, context: string): HmacDrbg

Parameters

• seed (Buffer) — 32-byte Buffer from which all randomness is derived. Must originate from a CSPRNG (e.g. crypto.randomBytes).
• context (string, default: "\"\"") — Domain-separation string. Used as personalization_string.

Returns

HmacDrbg

Methods

nextByte(): number

Returns the next byte from the DRBG output stream

Returns

• number

nextInt(max: number): number

Returns an unbiased random integer in [0, max) using rejection sampling. Rejects bytes that would introduce modular bias (FIPS 186-5 §B.4.2).

Parameters

• max (number) — Upper bound (exclusive). Must be in [2, 256].

Returns

• number