> 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/overview.md).

# Overview

VIDA Authentication Services provide multi-factor, biometric-first security to protect digital systems against unauthorized access and identity fraud. Leveraging facial biometrics, device binding, and PKI-backed cryptographic tokens, our platform ensures each authentication attempt is genuine and tamper-resistant.

With flexible integration methods like Phone Token, Face Token (via Liveness SDK or API), and Selfie ID, developers can choose the best fit for their app or platform. Whether you're securing logins, high-risk transactions, or continuous access, VIDA offers the tools to balance user experience with zero-compromise security.

| Name                                | Description                                                                                                                                                                                                                                   | Learn More                                                                                          |
| ----------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------- |
| **Cryptographic Token (PKI)**       | Leverages Public Key Infrastructure (PKI) to bind authentication to the user’s mobile device. Each action, such as login or payment is cryptographically signed using a Private Key and verified via VIDA’s Public Key, ensuring authenticity | [View Details](/identity-stack/authentication/authentication-factors/cryptographic-token-pki.md)    |
| **Biometric (Device + Face Token)** | Combines device binding with facial biometrics. Ensures the user is present (liveness) and matches the registered face.                                                                                                                       | [View Details](/identity-stack/authentication/authentication-factors/biometric-device-selfie-id.md) |