Trait RngProvider 

pub trait RngProvider:
    Send
    + Sync
    + 'static {
    // Required method
    fn fill_bytes(&self, dest: &mut [u8]);

    // Provided method
    fn next_u64(&self) -> u64 { ... }
}

Source of cryptographically secure random bytes.

The trait takes &self (not &mut self) on every method so a single Arc<dyn RngProvider> can be shared across tasks / threads without callers having to wrap it in a Mutex. Implementations that internally need mutation (a software DRBG, a ChaChaRng-backed test fixture, …) must supply their own interior mutability — see the CounterRng example in the test module.

Send + Sync + 'static lets the provider be held in Arc<dyn …> for the lifetime of a long-running listener.

Failure model

Implementations are expected to be infallible at the call boundary — randomness is required for crypto correctness, and there is no useful fallback at the Phantom Protocol layer. If the underlying source can fail (a hardware-RNG health-test trip, an OS RNG that returns EIO, …) the impl must surface that as a panic so the higher layer fails loudly rather than silently producing biased keys. The default OsRng follows this convention via getrandom’s Result::expect.

Required Methods

fn fill_bytes(&self, dest: &mut [u8])

Fill dest with cryptographically secure random bytes.

Provided Methods

fn next_u64(&self) -> u64

Convenience: return a single fresh u64 of randomness.

Default impl reads 8 bytes from fill_bytes and decodes them little-endian. Implementations with a faster word-aligned path (e.g., an HMAC-DRBG outputting 64-bit blocks) may override.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl RngProvider for OsRng

Available on non-crate feature fips only.