encryption for postgres

I need to save user ids and passwords to be used for access
to records in a database.  The passwords should be encrypted
before saving.  Are there builtin or standard php functions
to do encryption/decryption or does one need to add a library
to a standard php install (RedHat 7.1).

Cheers, Tom
Tom Hodges, hodges@xprt.net or tom_hodges@yahoo.com
ICQ 10149621, YahooMessenger tom_hodges
Mail: 14314 SW Allen Blvd, #317; Beaverton OR 97005 USA