openssl ecparam -name secp384r1 -genkey -out key.pem

openssl req -new -key key.pem -out request.csr \
  -subj "/CN=GTS Root R4/O=Google Trust Services LLC/"


openssl x509 -req -in request.csr -signkey key.pem -out cert.pem -days 999999 \
  -extfile openssl.cnf -extensions v3_ca 



cat key.pem cert.pem > mitmproxy-ca.pem