Security Model and Definitions

TOTP (Time-based One-Time Password, RFC 6238) generates a short code from a shared secret and a moving time step (typically 30 seconds). The code changes every interval and can be verified server-side with synchronized time.

HOTP (HMAC-based One-Time Password, RFC 4226) derives codes from a secret and incrementing counter. Unlike TOTP, validity depends on counter synchronization, not wall-clock time.

Passkeys are public-key credentials built on WebAuthn/FIDO2. Private keys stay on user devices and authentication uses challenge-response cryptography, which significantly reduces phishing risk compared with shared-secret OTP methods.

• Sensitive records are encrypted client-side before any sync
• Master keys are not transmitted to backend services
• Service-side systems operate on ciphertext for vault content
• Passkey credential material remains under platform credential management

Vault records use AES-256-GCM for confidentiality and integrity. Authenticated encryption protects against silent ciphertext tampering and rejects modified payloads at decrypt time.

No software tool eliminates all account risk. Endpoint compromise, phishing of fallback channels, and poor recovery hygiene can still result in account loss or unauthorized access.

The migration goal is to minimize these residual risks through better credential types, tighter recovery handling, and explicit account ownership controls.

Definitions and security terminology on this page are anchored to public standards and security guidance:

• RFC 6238: TOTP algorithm
• RFC 4226: HOTP algorithm
• W3C WebAuthn Level 2
• NIST SP 800-63B (Digital Identity Guidelines)
• FIDO Alliance: Passkeys overview
• OWASP Authentication Cheat Sheet