---
title: SecExternalFormat.formatX509Cert
framework: security
role: symbol
role_heading: Case
path: security/secexternalformat/formatx509cert
---

# SecExternalFormat.formatX509Cert

Format for certificates. DER (distinguished encoding rules) encoded. X.509 is a standard for digital certificates from the International Telecommunication Union (ITU). This is the default for certificates.

## Declaration

```swift
case formatX509Cert
```