what is a pem file

A PEM file is a container file format that is often used to store cryptographic keys. It can contain a certificate (public key), a private key, or both concatenated together. The format defines the structure and encoding type of the file used to store a bit of data. A single PEM file can contain multiple blocks of data that can be used in other programs. The file starts with "-----BEGIN <type>-----" and ends with "-----END <type>-----", with everything in between being base64 encoded. PEM files are commonly used to encode keyfiles, such as RSA keys used for SSH, and certificates used for SSL encryption. The typical PEM files are "key.pem" which contains the private encryption key, and "cert.pem" which contains certificate information. PEM files are a defined standard in RFCs 1421 through 1424. They are frequently required for certificate installations when multiple certificates are being imported as one file.