basalt / auth/src / matchTotpStep

Function: matchTotpStep()

> matchTotpStep(secret, token, options?): number | null

Defined in: auth/src/totp.ts:91

The TOTP step (counter) that token matches within the allowed window, or null. Constant-time over the window (no early exit → no timing side channel). The step is what enables replay prevention: persist the last-accepted step and reject any code whose step is ≤ it (RFC 6238 §5.2).

Parameters

secret

string

token

string

options?

VerifyTotpOptions = {}

Returns

number | null