SPDM RNG

Random number generator for SPDM protocol operations, implemented via OpenPRoT crypto service.

Overview

This crate implements the SpdmRng trait from spdm-lib by delegating to the centralized crypto service. All randomness is generated using ChaCha20 CSPRNG seeded from system entropy.

Architecture

SpdmCryptoRng → CryptoClient → IPC → CryptoServer → RustCryptoBackend → ChaCha20Rng

Security Model

• Entropy Source: getrandom crate (platform-dependent: hardware RNG, /dev/urandom, etc.)
• PRNG: ChaCha20 stream cipher (NIST approved, used in TLS 1.3)
• Seeding: Fresh seed from system entropy on each crypto service operation

Usage

use openprot_spdm_rng::SpdmCryptoRng;
use spdm_lib::platform::rng::SpdmRng;

let mut rng = SpdmCryptoRng::new(handle::CRYPTO);
let mut challenge = [0u8; 32];
rng.get_random_bytes(&mut challenge)?;

Future Enhancements

When AST1060 hardware RNG driver is available, only the crypto backend needs updating:

• Modify RustCryptoBackend::OneShot<GetRandomBytes> to use hardware RNG
• No changes needed to this crate or any SPDM code

Dependencies

• spdm-lib — SPDM protocol library
• crypto-client — OpenPRoT crypto service client

License

Apache-2.0