Skip to main content

What is a PEM file?

A PEM (Privacy Enhanced Mail Certificate) file is a text file with the following:

  • One or more blocks of text content, each block starting with -----BEGIN <type>----- and ending with -----END <type>-----

  • Text within each block that uses only uppercase and lowercase letters, digits, and “+” and “/” (Base64 ASCII encoding).

Among other uses, PEM files are a common way of holding SSL certificates and their associated private keys. SSL providers use the PEM file format to make this information available to the user concerned.

A PEM file relevant to CacheFly may therefore have a block starting with -----BEGIN CERTIFICATE----- and ending with -----END CERTIFICATE-----, or a block starting with -----BEGIN RSA PRIVATE KEY----- and ending with -----END RSA PRIVATE KEY-----.