The term “One-Time Passcodes (OTP)” refers to single-use codes for authentication or transaction approval. OTPs can be delivered via app (e.g., TOTP/HOTP), SMS, email, push notification, or voice call and expire after a short period or a single use. The goal is to reduce risks from intercepted or reused passwords and to add extra security layers (MFA/2FA).
Methods & Algorithms: Support for TOTP (time-based, RFC 6238) and HOTP (counter-based, RFC 4226) as well as one-time codes via email/SMS/voice.
Provisioning & Enrollment: User onboarding with QR-code/seed provisioning, recovery codes, device binding, and optional device trust.
Channels & Delivery: Multi-channel delivery (app, SMS, email, push, voice), fallback logic, resend flows, and deliverability checks.
Security Policies: Configurable code length, validity window, drift tolerance, maximum failed attempts, rate-limiting/throttling, lockouts, and recovery.
Protections: Replay protection, anti-brute-force controls, IP/device reputation, risk-/context-based evaluation with step-up authentication.
Key Management: Secure storage of secrets (e.g., HSM/KMS), rotation, revocation, audit trails, and versioning.
Developer Interfaces: REST/GraphQL APIs, SDKs for mobile/web, webhooks for events (e.g., “OTP verified”), multi-tenant support and tenant policies.
User Experience & Accessibility: Auto-fill/auto-read (where permitted), masking, localized texts/templates, offline app codes, and clear error/help messaging.
Compliance & Logging: GDPR-compliant processing, traceability (logging), reporting and monitoring (success rates, delivery times, failed attempts).
Administration: Per-app/group policies, exceptions (break-glass), recovery flows, and user self-service (e.g., channel change, token reset).
An employee logs into a SaaS dashboard and confirms the sign-in with a 6-digit TOTP from an authenticator app.
A customer receives a password reset code via email that is valid for 10 minutes.
A bank transfer is approved using an SMS OTP or app push (step-up authentication).
An admin authorizes a high-risk action (creating an API key) via a one-time code triggered by a push notification.
A new device login is verified with a voice-call OTP because the user has no app access.
During user onboarding in an HR system, the email address is verified using a one-time confirmation code.
Note: SMS/email OTPs increase security but are more susceptible to phishing and SIM-swap than app-based TOTP. A risk-based combination with clear policies is recommended.