先在StartSSL上申请免费一年的SSL证书，具体过程网上很多教程。然后把申请到的key和crt文件上传到服务器，比如/usr/local/nginx/certs/.

 Nginx配置SSL证书

直接贴上我的nginx的部分配置:

server {
        listen 443;
	server_name   liuzhichao.com www.liuzhichao.com ;
        ssl on;
        ssl_certificate /usr/local/nginx/ssl/ssl.crt;
        ssl_certificate_key /usr/local/nginx/ssl/ssl.key;if($http_transfer_encoding ~* chunked){return444;}

	gzip on;if(-d $request_filename){
		rewrite ^/(.*)([^/])$ $scheme://$host/$1$2/ permanent;}

	 root   /home/wwwroot/;

	 ssi off;
	 ssi_silent_errors off;
	 ssi_types text/shtml;

	 location /{
		 index  index.html index.htm index.shtml index.php;
		 autoindex	off;}

	location /nginx_status {
		stub_status on;
		access_log off;}

	 location ~(favicon.ico){ 
		 log_not_found off;
		 access_log   off;}

	 location ~* \.(gif|jpg|jpeg|png|bmp|swf)$ {
		 expires 1y;}

	 location ~* \.(js|css)$ {
		 expires 7d;}#------------
	 location ~*^(.+)\.(php[3-9]?|phtm[l]?)(\/.*)*$ {set $real_script_name $1.$2;set $path_info $3;if(!-f $document_root$real_script_name){return404;}

		  fastcgi_pass 127.0.0.1:8999; fastcgi_param HTTPS on;
		  include enable_php.conf;}}

现在重启Nginx，Chrome应该能正常显示Https.如果只想使用Https连接，可以再添加一个server，然后跳转到https

server {
        listen 80;
	server_name   liuzhichao.com www.liuzhichao.com ;
        rewrite     ^   https://$server_name$request_uri? permanent;}

 解决Firefox不信任StartSSL证书问题

wget http://cert.startssl.com/certs/ca.pem
wget http://cert.startssl.com/certs/sub.class1.server.ca.pem
cat ca.pem sub.class1.server.ca.pem >> ca-certs.crt
cat ca-certs.crt >> ssl.crt

再次重启Nginx，本想这下Firefox也应该能正常识别证书了，但是重启Nginx遇到了SSL: error:0906D066:PEM routines:PEM_read_bio:bad end line error错误。

[emerg]: SSL_CTX_use_certificate_chain_file("/usr/local/nginx/certs/ssl.crt")
 failed (SSL: error:0906D066:PEM routines:PEM_read_bio:bad end line error:140DC009:SSL routines:SSL_CTX_use_certificate_chain_file:PEM lib)
configuration file /usr/local/nginx/conf/nginx.conf test failed

这个的意思就是server.crt读取到意外错误行.这是因为我们在合并StartSSL提供的crt证书时，直接cat到了ssl.crt里。使用vi或者nano命令打开并编辑ssl.crt，找到：

-----END CERTIFICATE----------BEGIN CERTIFICATE-----

修改为：

-----END CERTIFICATE----------BEGIN CERTIFICATE-----

保存这个crt文件，再次重启Nginx服务，输入申请证书时私钥的密码,启动成功后，现在使用Firefox访问网站也能信任证书了。