thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Security Fundamentals & Crypto · Foundational

Privacy-Enhanced Mail Format (PEM)

Base64-encoded certificate or key format wrapped in -----BEGIN----- and -----END----- lines.

Definition

PEM is the most common text format for certificates, keys, and CSRs on Linux and web servers. A single PEM file can hold multiple certificates, such as a full chain. Extensions include .pem, .crt, .cer, and .key.

Example

openssl x509 -in cert.der -inform der -out cert.pem converts a DER certificate to PEM.

Exam tip

PEM is Base64 text; DER is binary. If you can read BEGIN CERTIFICATE, it's PEM.

Related terms