Struct NonceIssuer 

pub struct NonceIssuer { /* private fields */ }

Issues and checks nonces for one DIG-operated UDP STUN server process (SPEC.md §14.4). Holds nothing per-client: every issue/check call is a pure function of the secret, the source address, and the wall-clock second.

Implementations

impl NonceIssuer

pub fn new_random() -> Self

Build an issuer with a fresh, randomly generated secret (ring::rand::SystemRandom). The ordinary choice for a single-process deployment (SPEC.md §14.4 “Replicas”).

Panics

Only on catastrophic OS CSPRNG unavailability — the same posture as crate::new_transaction_id, for the same reason: there is no safe degraded fallback for a secret that must not be predictable.

pub fn from_secret(secret: [u8; 32]) -> Self

Build an issuer from an explicitly supplied secret — for a deployment running several server replicas behind one address that must share one issuer (SPEC.md §14.4 “Replicas”). The caller is responsible for generating and distributing secret safely; this constructor does no validation beyond the type system’s (any 32 bytes are accepted).

pub fn issue(&self, source: SocketAddr, now_unix_secs: u64) -> [u8; 20]

Mint a nonce for source at now_unix_secs, valid at THIS issuer for source alone, during the resulting bucket and the one after it (SPEC.md §14.4). Returns the raw 20 bytes; the caller base64url-encodes them into the wire NONCE attribute (crate::credential::encode_challenge does this).

pub fn check( &self, nonce_attr_value: &[u8], source: SocketAddr, now_unix_secs: u64, ) -> NonceCheck

Check a wire NONCE attribute value (the base64url text, exactly as carried) against source at now_unix_secs (SPEC.md §14.4). Recomputes the tag for the nonce’s OWN bucket (not now’s) before ever looking at freshness, so a forged nonce is Invalid rather than Stale regardless of what bucket number it claims.