> For the complete documentation index, see [llms.txt](https://docs.uidai.gov.in/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.uidai.gov.in/readme/app-to-app-credential-flows/uidai-specifications.md).

# UIDAI Specifications

UIDAI Specifications for PID Block Creation, Credential Exchange

### 1. Introduction

This is an API specification document to enable interaction between AUA/OVSE application and UIDAI's aadhaar app.

Aadhaar app released by UIDAI enables an AUA/OVSE application - app or portal to use face authentication using app-app intent or QR code intent in both android and ios environment. The aadhara provides following capabilities:

1. Secure interface to capture live person image for online Aadhaar auth/eKYC is supported by **CAPTURE intent** api. This intent provides pid block
2. Secure interface to capture live person image for offline match using UIDAI signed eKYC xml is supported by **OFFLINE FACE MATCH intent** api.
3. Secure interface to capture live person image for offline match using UIDAI signed eKYC xml is supported by **ONLINE FACE MATCH intent** api.
4. Secure exchange of the selective demographics attributes through **CREDENTIAL intent** api. Demographuic exchange could be with or without ONLINE or OFFLINE Face Authentication.

All Aadhaar enabled AUA applications to handle face biometric data in accordance to Aadhaar Registered Devices Technical Specification - version 2.0 (Revision 6)[**document link**](https://uidai.gov.in/images/resource/Aadhaar_Registered_Devices_2_0_4.pdf)

UIDAI has released a sample reference AUA/OVSE integration project to help developers quick start the headless app intents integration.