> For the complete documentation index, see [llms.txt](https://docs.vida.id/identity-stack/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.vida.id/identity-stack/authentication/introduction.md).

# Introduction

VIDA Authentication Services provide a secure, multi-factor authentication framework that combines **cryptographic device binding**, **facial biometrics**, and **identity verification** to protect applications from unauthorized access and fraud. By integrating **Public Key Infrastructure (PKI)** with advanced biometric technologies, VIDA ensures that only verified users and trusted devices can initiate high-risk actions such as logins, payments, or approvals.

The platform supports multiple authentication methods, including

* **Cryptographic Token (Phone Token):** A tamper-proof, PKI-based credential tied to a user’s mobile device.
* **Biometric (Device + Face Token):** Combines device-bound credentials with facial recognition and liveness detection.
* **Selfie ID:** Matches a live selfie against an enrolled image for re-authentication or step-up verification.

### Why Choose VIDA Authentication Services?

* **Tamper-Proof Security**: PKI-backed device authentication ensures that only trusted devices can initiate transactions.
* **Advanced Biometric Verification**: Combines face matching and liveness detection for secure and user-friendly authentication.
* **Fraud Prevention**: Stops tampered apps, cloned devices, and spoofing attacks in their tracks.
* **User Trust**: Provides peace of mind by ensuring all transactions are genuine and secure.