Key and certificate file formats

Files that hold cryptographic material: private and public keys, and the certificates that bind a public key to a name and are signed by someone who vouches for it. Web servers, email, code signing and SSH all depend on them.

Formats

.ASC

OpenPGP key

PGP and GnuPG keys: OpenPGP packets, as binary or base64 armour.

.DER

DER-encoded certificate or key

Certificates and keys in binary ASN.1: tag, length and value fields.

.JKS

Java KeyStore

Java’s older keystore: named keys and certificates, closed by a SHA-1 hash.

.PEM

Privacy-Enhanced Mail encoding

Keys and certificates as base64 text between BEGIN and END lines.

.PFX

PKCS #12 key and certificate bundle

A private key and its certificates in one password-protected file.

.PUB

OpenSSH public key

An SSH public key on one line: type, base64 key and a comment.