Here, we will demonstrate how to enable PostgreSQL to use SSL for protection of database connections by encrypting all of the data passed over that connection. Using SSL makes it much harder to sniff the database traffic, including usernames, passwords, and sensitive data that are passed between a client and the database by someone listening to a network somewhere between them. An alternative to using SSL is running the connection over a Virtual Private Network (VPN).

Using SSL makes the data transfer on the encrypted connection a little slower, so you may not want to use it if you are sure that your network is safe. The performance impact can be quite large if you are creating lots of short connections, as setting up an SSL connection is quite CPU-heavy. In this case, you may want to run a local connection pooling solution, such as PgBouncer, to which you connect without encryption, and make the SSL-protected connection using stunnel, as described in the PgBouncer FAQ...