---
title: certificationDeclaration
framework: matter
role: symbol
role_heading: Instance Property
path: matter/mtrdeviceattestationdeviceinfo/certificationdeclaration
---

# certificationDeclaration

The certification declaration of the device, if available.  This is a DER-encoded string representing a CMS-formatted certification declaration.  May be nil only if attestation verification failed.

## Declaration

```swift
var certificationDeclaration: Data? { get }
```