DER encoded RSA private key

DER encoded RSA private key is a private key format that stores the same information as PEM encoded RSA private key, but encoded in DER format instead of PEM format.

Examples
To view the contents of a file: openssl rsa -noout -text -inform DER -in example-der.key

To convert to PEM encoded RSA private key format: openssl rsa -inform DER -in example-der.key -out example-pem.key

Software

 * OpenSSL