.CER File Extension

A .CER file is a Internet Security Certificate, created by N/A.

Open with Mozilla Firefox. Available for Linux, Windows, and Mac.

What is a .CER file?

A .CER file is a type of digital file known as an Internet Security Certificate. These files are used to help secure and authenticate the identity of a website. They are issued by trusted organizations called Certificate Authorities, such as VeriSign or Thawte. When a .CER file is installed on a web server, it serves as a form of verification that the website hosted on that server is genuine and secure. This is important for ensuring safe communications and transactions over the internet.

You can open a .CER file using various programs and web browsers. Popular web browsers like Mozilla Firefox, Google Chrome, Microsoft Edge, and Apple Safari can all handle .CER files. These browsers use the certificate to check the security of websites you visit. Additionally, software like Adobe Acrobat Reader DC and Adobe Acrobat DC can also open .CER files, typically to verify digital signatures on PDF documents. For Mac users, Apple Keychain Access, which is included with the operating system, allows you to manage .CER files by adding them to your keychain for system-wide use. This helps in automatically trusting the certificates for any applications that require them.


Our goal is to help people find the most up-to-date information about file extensions for Windows, Mac, Linux, Android and iOS. We researched over 10,000 file extensions and their respective programs that open those files. If you want to suggest edits or updates about .CER file formats, example files, or programs that are compatible. Please contact us.

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