加密HTTP協議，也就是HTTPS用到的SSL證書，幾個免費的地方
1、騰訊雲DV SSL 證書
https://cloud.tencent.com/product/ssl
2、Let’s Encrypt
https://letsencrypt.org/
4、CloudFlare SSL
https://www.cloudflare.com/
4、StartSSL
https://www.startcomca.com/
5、Wosign沃通SSL
https://www.wosign.com/
6、loovit.net AlphaSSL
https://www.lowendtalk.com/entry/register?Target=discussion%2Fcomment%2F2306096