Use the openssl command to convert between formats as follows:

0. To convert a certificate from PEM to DER:
0. x509 –in input.crt –inform PEM –out output.crt –outform DER
0. To convert a certificate from DER to PEM:
0. x509 –in input.crt –inform DER –out output.crt –outform PEM
0. To convert a key from PEM to DER:
0. rsa –in input.key –inform PEM –out output.key –outform DER
0. To convert a key from DER to PEM:
0. rsa –in input.key –inform DER –out output.key –outform PEM