.cer is Internet Security Certificate
| Feature | Description |
|---|---|
| File extension | .cer |
| File format | X.509 |
| Purpose | To verify the identity of a website or server |
| Contents | The public key of the website or server, as well as the signature of a certificate authority (CA) |
What's on this Page
A CER file is a certificate file that contains the public key of a website or server. It is used to verify the identity of the website or server and to encrypt data that is sent between the website or server and the user's browser.
CER and CRT files are both types of certificate files, but they have different file extensions. CER files have the file extension .cer, while CRT files have the file extension .crt. The two file formats are technically the same, but they are often used for different purposes. CER files are typically used by web browsers to verify the identity of websites, while CRT files are typically used by operating systems to verify the identity of software.
There are a few different ways to open a CER file. You can use a text editor to view the contents of the file, or you can use a certificate viewer program to view and verify the certificate. Some popular certificate viewers include OpenSSL, Keychain Access, and Firefox's Certificate Manager.
To install a CER file on a web server, you will need to upload the file to the server's web root directory. Once the file is uploaded, you will need to configure your web server to use the certificate. The specific steps for configuring your web server will vary depending on the type of web server that you are using.
You can verify the authenticity of a CER file by using a certificate viewer program. Most certificate viewer programs will allow you to check the validity of the certificate, as well as the identity of the certificate authority that issued the certificate.
There are a few different ways to convert a CER file to another format. One way is to use a certificate converter program. There are a number of free and commercial certificate converter programs available. Another way to convert a CER file is to use a text editor to manually convert the file format.
The purpose of a CER file is to verify the identity of a website or server. When a user visits a website, the user's browser will check the website's certificate to make sure that the website is who it claims to be. If the certificate is valid, the user's browser will encrypt the data that is sent between the user's computer and the website. This helps to protect the user's data from being intercepted by third parties.
Certificate authorities (CAs) generate CER files. CAs are trusted organizations that are responsible for issuing digital certificates. When a website or server wants to obtain a digital certificate, they will need to submit a request to a CA. The CA will then verify the identity of the website or server and issue a digital certificate.
You can get a CER file from a CA. You can also get a CER file from the website or server that you want to visit. The website or server will typically provide a link to the CER file on their website.
CER files need to be updated when the website or server's certificate expires. The certificate will typically expire every one to three years. When the certificate expires, the website or server will need to obtain a new certificate from a CA.
There are a few security risks associated with CER files. One risk is that a malicious actor could create a fake CER file that appears to be from a legitimate website or server. If a user's browser trusts the fake CER file, the user's data could be intercepted by the malicious actor. Another risk is that a CER file could be compromised if the website or server's private key is stolen. If the private key is stolen, the attacker could use the key to create fraudulent certificates.