Struct HotpManager 

pub struct HotpManager { /* private fields */ }

HOTP manager for generating and validating counter-based OTPs.

Implementations

impl HotpManager

pub fn new(config: HotpConfig) -> Self

Create a new HOTP manager with the given configuration.

pub fn with_defaults() -> Self

Create a new HOTP manager with default configuration.

pub fn generate_secret() -> Result<String>

Generate a cryptographically random 20-byte secret encoded as RFC 4648 Base32 (with padding).

pub fn generate(&self, secret_b32: &str, counter: u64) -> Result<String>

Generate an HOTP code for the given secret and counter value.

Implements RFC 4226 §5.3 — Dynamic Truncation.

pub fn validate( &self, secret_b32: &str, counter: u64, code: &str, ) -> Result<Option<u64>>

Validate an HOTP code against the expected counter value.

On success, returns the counter value that matched (which may be ahead of counter by up to look_ahead_window). The caller should persist matched_counter + 1 as the new expected counter.