This article explains what PEM files are used for, how to open them depending on the program or operating system you are using, and how to convert them to another certificate file format.
What is a PEM file and how do you use it?
A PEM file is a Privacy Enhanced Mail Certificate file that is used to send email privately. The person receiving that email can be sure that the message was not modified in transit, was not shown to anyone else, and was sent by the person claiming to have sent it.
PEM files were born out of the complication of sending binary data via email. The PEM format encodes binary using base64, so it exists as an ASCII string.
The PEM format has been replaced by newer and more secure technologies, but the PEM container is still used to store certificate authority files, public and private keys, root certificates, and so on.
