convert pem to der (crt)

# generate param key
openssl dsaparam -out dsaparam.pem 2048

# generate private key
openssl gendsa -out privatekey.pem dsaparam.pem

# generate certificat
openssl req -new -x509 -key privatekey.pem -out cert.pem -days 365

# convert to der (crt) format
openssl x509 -outform der -in cert.pem -out cert.crt