Crate nist_rand 

nist-rand — SP 800-90A/B/C CSPRNG Implementation

⚠️ DISCLAIMER: This code is NOT FIPS Verified and has NOT been officially audited by a NIST lab. Furthermore, this code does not receive any formal security audits. It implements the best practices and algorithms described by NIST SP 800-90A/B/C, but does not claim or provide official compliance or certification. Use at your own risk.

A high-assurance, production-ready Cryptographically Secure Pseudorandom Number Generator (CSPRNG) that implements the architectural design and algorithms described in NIST SP 800-90A/B/C.

Architecture

 ┌───────────────────────────────────────────────────────────────┐
 │                    SP 800-90C Blender                         │
 │  ┌──────────────┐  ┌────────────────┐  ┌──────────────────┐   │
 │  │ OS RNG       │  │ CPU Jitter     │  │ System State     │   │
 │  │ /dev/urandom │  │ (advance feat) │  │ /proc, TSC, ASLR │   │
 │  │ + 90B tests  │  │ Von Neumann    │  │ (advance feat)   │   │
 │  └──────┬───────┘  └───────┬────────┘  └────────┬─────────┘   │
 │         └──────────────────┴────────────────────┘             │
 │                            │ SHA3-512                         │
 └────────────────────────────┼──────────────────────────────────┘
                              │ 512-bit conditioned seed
 ┌────────────────────────────▼──────────────────────────────────┐
 │             Hash_DRBG (SP 800-90A § 10.1.1)                   │
 │                    SHA3-512 (FIPS 202)                        │
 │                reseed every 10 000 requests                   │
 └────────────────────────────┬──────────────────────────────────┘
                              │
                        fill() / NistRng

SP 800-90 Design Principles

Requirement	Standard	Implementation
Entropy source health tests	SP 800-90B § 4.4	rng::HealthTests (RCT + APT)
Multi-source entropy blending	SP 800-90C § 4.1	entropy::get_blended_entropy() with SHA3-512
Approved DRBG mechanism	SP 800-90A § 10.1.1	drbg::HashDrbg
Approved hash function	FIPS 202	SHA3-512
Reseed interval enforcement	SP 800-90A Table 2	Panic-on-overrun after 10 000 calls
Fail-safe on entropy failure	FIPS 140-3 § 9.2 (Aligns with)	panic! on health-test or reseed failure

Crate Features

Feature	Default	Description
rand_core	✓	Exposes NistRng implementing rand_core 0.10 traits
advance	✓	Adds CPU jitter, System state, and Hardware RNG (RDSEED/RDRAND) + extended 90B health tests
build_separator	✓	Embeds a random build-time salt (via build.rs)
zeroize	✓	Derives zeroize::ZeroizeOnDrop on HashDrbg; wraps all sensitive buffers in zeroize::Zeroizing so keying material is erased even on panic
exp_simd_rng	✗	Experimental: AVX-256 thermal jitter (implies advance)
exp_network_rng	✗	Experimental: UDP network-latency jitter (implies advance)

Modules

drbg

Hash_DRBG (SP 800-90A § 10.1.1) backed by SHA3-512.

entropy

Entropy sources and SP 800-90B continuous health tests.

rng

OS RNG reader and HealthTests state machine.

Structs

NistRngrand_core

A rand_core 0.10-compatible wrapper around the nist-rand pipeline.

NistRngPredictionResistantrand_core

A rand_core 0.10-compatible wrapper providing Prediction Resistance.

Functions

fill

Fills dest with cryptographically secure random bytes.

fill_prediction_resistant

Fills dest with cryptographically secure random bytes, with guaranteed Prediction Resistance (SP 800-90A § 8.7.2).

reseed

Forces an immediate reseed of the thread-local DRBG using fresh, SP 800-90C-conditioned entropy.