现在的nginx应该是只能从本地文件中读取证书。不过，应该可以修改代码添加通过http/tcp方式从远端服务器读取证书的方式。应该不是很困难。

低版本，编译会打印md5和sha1。我测试1.10版本，是打印md5和sha1的，1.11以上不打印了，可以查看
https://github.com/nginx/nginx/tree/master源代码代码仓库auto/summary文件，里面有描述。下面为我本地Ubuntu18.04编译指令：
在代码根目录运行，./auto/configure --prefix=/opt/nginx --with-http_stub_status_module --with-http_ssl_module --with-stream --with-stream_ssl_module --add-module=/home/lq/work/tongmingzhiyun/openresty/lua-nginx-module-0.10.21 --add-module=/home/lq/work/tongmingzhiyun/openresty/ngx_devel_kit-0.3.1
Configuration summary
+ using system PCRE library
+ using system OpenSSL library
+ md5: using OpenSSL library
+ sha1: using OpenSSL library
+ using system zlib library

nginx path prefix: "/opt/nginx"
nginx binary file: "/opt/nginx/sbin/nginx"
nginx modules path: "/opt/nginx/modules"
nginx configuration prefix: "/opt/nginx/conf"
nginx configuration file: "/opt/nginx/conf/nginx.conf"
nginx pid file: "/opt/nginx/logs/nginx.pid"
nginx error log file: "/opt/nginx/logs/error.log"
nginx http access log file: "/opt/nginx/logs/access.log"
nginx http client request body temporary files: "client_body_temp"
nginx http proxy temporary files: "proxy_temp"
nginx http fastcgi temporary files: "fastcgi_temp"
nginx http uwsgi temporary files: "uwsgi_temp"
nginx http scgi temporary files: "scgi_temp"