2017.9.5 postgresql加密函数的使用

需要安装的插件的名字：pgcrypto

官网地址：https://www.postgresql.org/docs/9.4/static/pgcrypto.html

stackoverflow:

https://stackoverflow.com/questions/8000740/how-do-i-install-pgcrypto-in-postgresql-9-1-on-windows/46046367#46046367

https://stackoverflow.com/questions/2647158/how-can-i-hash-passwords-in-postgresql

具体步骤：

1.add the extensions: create extension pgcrypto

2.check the extensions: select * from pg_available_extensions 

3.use the extensions: select '{SHA}'||encode(digest('test', 'sha1'), 'base64');