rp2040_entropy

A conditioned, best-effort RP2040 entropy seed.

The RP2040 has no cryptographic random-number generator. Its ring oscillator exposes one jitter-derived bit, which this driver samples no faster than once every 10 microseconds and conditions with SplitMix64. This follows the source and timing policy used by the Raspberry Pi Pico SDK, but deliberately does not claim cryptographic strength. Use the result to diversify non-secret PRNG state; do not generate keys from it.

Structs

BestEffortSeed

struct BestEffortSeed {
    pub words: [u64; 2],
    pub health: EntropyHealth,
}

A conditioned seed whose quality is explicitly best effort, not crypto.

Implements: Clone, Copy, Debug, Eq, PartialEq, StructuralPartialEq

References: EntropyHealth

EntropyHealth

struct EntropyHealth {
    pub bits: u16,
    pub ones: u16,
    pub transitions: u16,
}

Health evidence about the raw ROSC bits before conditioning.

Implements: Clone, Copy, Debug, Eq, PartialEq, StructuralPartialEq

Enums

EntropyError

enum EntropyError {
    OscillatorDisabled,
    SystemClockUsesOscillator,
}

Why the raw source could not safely be sampled.

Implements: Clone, Copy, Debug, Eq, From, PartialEq, StructuralPartialEq