pub fn hotp(secret: &[u8], counter: u64) -> StringExpand description
HOTP (RFC 4226) for one counter value, SHA-1 and six digits.
The login path’s shape. A stored third-party seed goes through
hotp_with, which is the same function with the two constants unpinned;
this one stays because every caller in users.rs means exactly these
numbers and spelling them out at each call site invites one of them to
drift.