A PEM file is a text file used to store digital certificates. It uses plain text headers and footers to indicate the beginning and end of the certificate data, which is encoded in Base64. PEM files of...
A PEM file is a text file used to store digital certificates. It uses plain text headers and footers to indicate the beginning and end of the certificate data, which is encoded in Base64. PEM files often use extensions like .crt, .cer, and .key to indicate what type of data is inside.
Opening a PEM file in a text editor shows the marked headers and footers around the encoded data sections. PEM files can be opened on various operating systems, but mobile devices may not properly support the format.
In contrast to PEM, DER files store certificates in binary format. DER is more compact but not human-readable like PEM. PEM certificates and keys can be converted to DER using utilities like OpenSSL.
A PEM file can contain multiple certificates and keys, with each one delimited by header and footer lines. For example:
PEM files themselves do not have a standard file extension. The extension indicates what type of data is inside – .crt and .cer for certificates, .key for private keys, etc. Programs needing to process the PEM file need to understand the file’s internal structure to parse it correctly.
We have provided tips on opening PEM files across operating systems, along with a list of compatible software. Please let us know if you need any other assistance working with PEM files.
OpenSSL
Apache HTTP Server
nginx