One of the most powerful modules in the entire contrib module section is pgcrypto. It was originally written by one of the Skype sysadmins and offers countless functions to encrypt and decrypt data.
It offers functions for symmetric as well as asymmetric encryption. Due to the large number of functions, it is definitely recommended to check out the documentation page: https://www.postgresql.org/docs/current/static/pgcrypto.html.
Due to the limited scope of this chapter, it is impossible to dig into all the details of the pgcrypto module.
