将SHA-1证书更换为SHA-256证书
Migrating SSL Certificate from SHA-1 to SHA-256
SHA-256算法CSR生成命令：
openssl req -new -newkey rsa:2048 -nodes -sha256 -out wildcard.domain.tld.sha256.csr -keyout wildcard.domain.tld.key
Nginx SSL配置如下：
listen 443 ssl spdy;
ssl_certificate sha256.crt;
ssl_certificate_key sha256.key;
ssl_session_timeout 10m;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:EDH-DSS-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:!aNULL:!eNULL:!EXPORT:!CAMELLIA:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA:!DES-CBC3-SHA;
ssl_prefer_server_ciphers on;
ssl_session_cache shared:SSL:5m;
ssl_stapling on;
ssl_stapling_verify on;
ssl_trusted_certificate ca-certs.pem;
resolver 74.82.42.42 8.8.8.8;
add_header Strict-Transport-Security "max-age=31536000";