DER files are digital certificates in binary format, instead of the instead of the ASCII PEM format. DER files may end with .der or .cer, so to differentiate between DER.cer and PEM.cer files, you may need to use a text editor to read the file. Both digital certificates and private keys can be encoded in DER format.
Hereof, what is a DER file?
.pem , .cer and .der are all file extensions for files that usually contain a X.509 v3 certificate. DER is the method of encoding the data that makes up the certificate. DER itself could represent any kind of data, but usually it describes an encoded certificate or a CMS container. .cer just stands for certificate.
What is Der certificate?
.DER = The DER extension is used for binary DER encoded certificates. .PEM = The PEM extension is used for different types of X.509v3 files which contain ASCII (Base64) armored data prefixed with a “—– BEGIN …” line.
What is PEM encoded certificate?
PEM or Privacy Enhanced Mail is a Base64 encoded DER certificate. PEM certificates are frequently used for web servers as they can easily be translated into readable data using a simple text editor. -----BEGIN CERTIFICATE----- and -----END CERTIFICATE----- show a certificate file in PEM format.