How to create ECDSA P-384 (secp384r1) using OpenSSL (-newkey)
In order to generate a ECDSA certificate using the P-384 curve, use the following form of the -newkey argument:
-newkey ec:<(openssl ecparam -name secp384r1)
Example:
openssl req -newkey ec:<(openssl ecparam -name secp384r1) -nodes -x509 -keyout ca.key -out ca.pem -days 365000