---
title: Storing a DER-Encoded X.509 Certificate
framework: security
role: article
role_heading: Article
path: security/storing-a-der-encoded-x-509-certificate
---

# Storing a DER-Encoded X.509 Certificate

Import and export a certificate from a file.

## Overview

Overview Certificates are not secret and you often want to share them to disseminate a public key, but SecCertificate is an opaque type that you can’t distribute directly. Instead, you create a Distinguished Encoding Rules (DER) encoded data representation of the certificate using the SecCertificateCopyData(_:) function: You might send this data object over a network connection or store it in a .cer file: When you receive such a data object, you use the SecCertificateCreateWithData(_:_:) function to reverse the process: By leaving the first argument empty, you rely on the default allocator to allocate memory for the certificate. Note that in Objective-C, you call CFRelease to free the certificate’s memory when you are done with it. In Swift, the system manages the object’s memory automatically.