File Extension Database

Open CER File

CER extension files are security files provided and generated by a certification authority.

These files help the browser to verify if a website is secure and accessible without risk, verifying its authenticity.

These CER security certificates are typically installed on a web server.

If a user enters a URL to a website hosted on the same server, the browser checks the validity of the website by checking the attached certificate.

The public certificate included in the CER file maps a public key to a specific identity using a digital signature, which verifies the website.

Different encryption algorithms, such as Base 64 and DER, can be used to encrypt the contents of a CER certificate.

When browsing a validated website, the corresponding CER certificate can be viewed by clicking the padlock icon located on the browser page (usually located on the edge).

It is available for SSL-encrypted websites and can be easily detected by the "https://" prefix in the URL.

By double-clicking on said lock, it is possible to see the information contained in the CER file, at least in Edge, Firefox and Safari.

Software to open and work with a CER file

Typical CER application file locations:

  • %SystemRoot%\system32\rundll32.exe cryptext.dll
  • C:\Windows\system32\rundll32.exe cryptext.dll,CryptExtOpenCER %1

Typical CER mime types:

  • CryptExtOpenCER %1
  • application/x-x509-ca-cert

Frequently associated Windows objects:

  • CERFile

How Can I Open CER File on Windows

How Can I Open CER File on Mac OS

How Can I Open CER File on Android

If you downloaded a CER file on Android device you can open it by following steps below:

How to Open CER File on iPhone or iPad

To open CER File on iOS device follow steps below:

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CER file article translations

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