Certificates and keys
A category of file formats covered by Format Atlas.
About this category
CRTCRT and CER are extensions often used for X.509 certificates. The extension alone does not tell whether the file uses PEM text or DER binary encoding.CSRA CSR contains a public key and requested identity information, signed using the corresponding private key. It is submitted to a certificate authority; it is not an issued certificate.DERDER is a binary encoding of ASN.1 structures. A .der file may hold a certificate or another structure; identify its contents before use.PEMPEM encodes certificate-related structures as Base64 text between BEGIN and END labels. A .pem extension can contain a certificate, public key, private key, or other material.PFXPFX and P12 are extensions for PKCS#12 containers. They may include a private key and certificate chain, so handle the file and password securely.