> 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/authentication-factors/cryptographic-token-pki/integration-methods/sdk/android-development-kit/initializing-the-framework.md).

# Initializing the Framework

CredentialServicesKit establishes authentication with the VIDA Auth Credential Services by utilizing a bearer token.  Please refer to acquire bearer token flow  at API [authentication](/identity-stack/authentication/authentication-factors/cryptographic-token-pki/integration-methods/api/authentication.md) to get the bearer token.

To update the framework with a bearer token, the method `SetToken(context: Context, token: String)` should be invoked.

{% hint style="info" %}

* The bearer token expires in 300 seconds. 
* An expired token used for device registration shall return an error code 20018.
* Signatures can be generated even when the token has expired.
  {% endhint %}