PEM (Privacy Enhanced Mail) is a file format used to store cryptographic keys, certificates, and other sensitive data. PEM files are typically encoded in Base64, making them human-readable, and are often used for secure communication and authentication. They are commonly used in SSL/TLS configurations for web servers, VPNs, and other security-related applications. A PEM file usually contains a header and footer that clearly identify the type of data it holds, such as a private key, public key, or certificate. The data between the header and footer is the Base64-encoded representation of the actual cryptographic information. PEM format is a widely accepted standard for exchanging cryptographic keys and certificates across different systems and platforms. It's essential to handle PEM files with care, as they often contain sensitive information that could compromise security if exposed.