Skip to main content

Authentication Layer Overview

The Authentication Layer of Interstellar is responsible for verifying user identity and validating intent across sensitive operations such as transaction approvals and account recovery. It leverages both biometric factors and hardware-backed signatures via the device’s Secure Element (SE).

At its core, the layer is built around the Trusted Action Validation Protocol (TAVP) — previously referred to as TTVP — which enables secure, human-verified input through the use of randomized keypads and visual cryptography rendered in real time by the mobile device.

Core Components​

  • Biometric Authentication

    • Native biometric unlock (Face ID, fingerprint)
    • Unlocks SE for validation and key usage

  • TAVP (Trusted Action Validation Protocol)

    • Combines biometric unlocking, visual confirmation, randomized input, and SE signing
    • Protects user actions (e.g. transfers, recovery) from spoofing or malware interference

  • AUTH Extrinsics

    • AUTH-REQ: Initiates the validation challenge
    • AUTH-RSP: Returns the user’s SE-signed confirmation input

This layer is already implemented in Milestone 1 and is fully compatible with DSP2 and SCA requirements. Future updates will expand it to support on-device passkey emulation, secure delegation approvals, and wallet-level policy enforcement.