How can I get access to password hashing in postgresql? Tried installing postgresql-contrib in ubuntu, still can't access hashing functions

So I'm trying to just hash some passwords in postgresql, and the only hashing solution that I've found for postgresql is part of the pgcrytpo package ( http://www.postgresql.org/docs/8.3/static/pgcrypto.html ) that is supposed to be in postgresql-contrib ( http://www.postgresql.org/docs/8.3/static/contrib.html ).

So I installed postgresql-contrib, (sudo apt-get install postgresql-contrib), restarted my server (as a simple way to restart postgresql).

However, I still don't have access to any of the functions for hashing that are supposed to be in postgresql-contrib, e.g.:

ninjawars=# select crypt('global salt' || 'new password' || 'user created date', gen_salt('sha256'));
ERROR:  function gen_salt(unknown) does not exist

ninjawars=# select digest('test', 'sha256') from players limit 1;
ERROR:  function digest(unknown, unknown) does not exist

ninjawars=# select hmac('test', 'sha256') from players limit 1;
ERROR:  function hmac(unknown, unknown) does not exist

So how can I hash passwords in postgresql, on ubuntu?