openssl req -new -x509 -days 3650 -nodes -out server.crt -keyout server.key -subj "/C=XX/L=Default City/O=Default Company Ltd/"指定证书为2048位RSA：
openssl req -newkey rsa:2048 -x509 -days 3650 -nodes -out server.crt -keyout server.key -subj "/C=XX/L=Default City/O=Default Company Ltd/"查看证书信息：
openssl x509 -text -noout -in server.crt 生成ecc证书：
openssl ecparam -genkey -name prime256v1 -out server.key
# -name secp384r1
openssl req -new -x509 -days 3650 -key server.key -out server.cert标签：none