Privacy Enhanced Mail (PEM) files are concatenated certificate containers frequently used in certificate installations when multiple certificates that form a complete chain are being imported as a single file. They are a defined standard in RFCs 1421 through 1424. They can be thought of as a layered container of chained certificates. A .pem file is a container format that may just include the public certificate or the entire certificate chain (private key, public key, root certificates):
- Private Key
- Server Certificate (crt, puplic key)
- (optional) Intermediate CA and/or bundles if signed by a 3rd party
How to create a self-signed PEM file:
openssl req -newkey rsa:2048 -new -nodes -x509 -days 3650 -keyout key.pem -out cert.pem
How to create a PEM file from existing certificate files that form a chain:
- (optional) Remove the password from the Private Key by following the steps listed below:
- Type openssl rsa -in server.key -out nopassword.key and press Enter.
- Enter the pass phrase of the Private Key.
- Combine the private key, public certificate and any 3rd party intermediate certificate files:
- cat nopassword.key > server.pem
- cat server.crt >> server.pem
- Repeat this step as needed for third-party certificate chain files, bundles, etc:
cat intermediate.crt >> server.pem
- Download NetIQ Cool Tool OpenSSL-Toolkit.
- Select Create Certificates | PEM with key and entire trust chain
- Provide the full path to the directory containing the certificate files.
- Provide the filenames of the following:
- private key
- public key (server crt)
- (conditional) password for private key
- (conditional) any intermediate certificate chain file(s)
For additional information, please see TID 7015502 - Common Mistakes in SSL Certificate Management & Implementation.
The following details the structure of a typical .pem file (including the entire certificate chain):
-----BEGIN RSA PRIVATE KEY-----
(Private Key: domain_name.key contents)
-----END RSA PRIVATE KEY-----
(Primary SSL certificate: domain_name.crt contents)
(Intermediate certificate: certChainCA.crt contents)