Varmistusonetimepassword

Varmistusonetimepassword is a term used to describe a one-time password used to verify a user's identity in authentication processes. It forms a common component of two-factor authentication (2FA) and multi-factor authentication (MFA).

OTPs are generated by algorithms such as HOTP and TOTP (standards RFC 4226 and RFC 6238). A six- or eight-digit code is typically valid for a short time window or for a single use, after which it becomes useless.

Delivery methods include software authenticator apps, hardware tokens, SMS messages, or email. In enterprise settings, OTPs may be integrated with identity providers and access management systems.

Security considerations: OTPs improve security by requiring possession of the verification device, but they can be compromised via phishing, malware, or SIM-swapping in SMS deliveries. Therefore, OTPs are often combined with other controls and phishing-resistant methods when possible, such as WebAuthn or FIDO2 tokens.

Implementation notes: configure reasonable code lengths, use secure channels (HTTPS), protect secret seeds, enforce rate limiting and lockouts, and rotate secrets. Educate users about phishing and device security.

See also: two-factor authentication, one-time password, TOTP, HOTP, WebAuthn.