Struct Challenge 

pub struct Challenge {
    pub bytes: Vec<u8>,
    pub created_at: SystemTime,
}

A single-use challenge issued by the relying party before a ceremony.

Security contract: each Challenge must be used at most once and must expire after a short window (typically 60–300 seconds). The caller is responsible for enforcing both properties.

Fields

bytes: Vec<u8>

32 cryptographically random bytes.

created_at: SystemTime

When this challenge was generated — used for expiry checks.

Implementations

impl Challenge

pub fn new() -> Result<Self>

Generate a fresh 32-byte challenge using the OS cryptographic RNG.

32 bytes provides 256 bits of entropy — far beyond any brute-force threat.

Errors

Returns WebAuthnError::InvalidClientData if the system RNG fails (extremely unlikely; would indicate a kernel-level failure).

pub fn is_expired(&self, ttl_secs: u64) -> bool

Returns true if this challenge is older than ttl_secs seconds.

Returns true if the system clock has gone backwards since the challenge was created — treating an unverifiable age as expired is the safe default.

Trait Implementations

impl Clone for Challenge

fn clone(&self) -> Challenge

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Challenge

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.