Can't run digest() on PosrgreSQL 9.3 on RDS Following the advice given on another answer, I tried using the digest() function on PostgreSQL 9.3 on AWS RDS:

devdb=&gt; SELECT digest('blah', 'sha1');
ERROR:  function digest(unknown, unknown) does not exist
LINE 1: SELECT digest('blah', 'sha1');
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.


Even though pgcrypto exist:

devdb=&gt; SHOW rds.extensions;



  btree_gin,btree_gist,chkpass,citext,cube,dblink,dict_int,dict_xsyn,earthdistance,fuzzystrmatch,hstore,intagg,intarray,isn,ltree,pgcrypto,pgrowlocks,pg_trgm,plperl,plpgsql,pltcl,postgis,postgis_tiger_geocoder,postgis_topology,sslinfo,tablefunc,tsearch2,unaccent,uuid-ossp


How can I enable the digest() function?

Updates

I have co-asked on the AWS RDS forum, will posts mutually updated.

digest() does not seem to exist on the db:

devdb=&gt; \df digest
                       List of functions
 Schema | Name | Result data type | Argument data types | Type
--------+------+------------------+---------------------+------
(0 rows)
The question was answered at the AWS forum by Shawn@AWS - The rds.extension list shows available, rather than installed, modules.

Thank you for using RDS Postgres. The &quot;rds.extension&quot; parameter shows you what extensions are available in RDS Postgres. You still need to execute the &quot;create extension&quot; command.
Using your test case:

postgres=&gt; show rds.extensions;
... ,pgcrypto, ...
postgres=&gt; create extension pgcrypto;
CREATE EXTENSION

postgres=&gt; SELECT digest('blah', 'sha1');
digest
\x5bf1fd927dfb8679496a2e6cf00cbe50c1c87145
(1 row)

Addendum
pg_available_extensions shows which extensions are available and which are already installed:
postgres=&gt; SELECT * FROM pg_available_extensions;

          name          | default_version | installed_version |                               comment
------------------------+-----------------+-------------------+---------------------------------------------------------------------
 chkpass                | 1.0             |                   | data type for auto-encrypted passwords
 xml2                   | 1.0             |                   | XPath querying and XSLT
 plpgsql                | 1.0             | 1.0               | PL/pgSQL procedural language
 pgcrypto               | 1.0             |                   | cryptographic functions
 postgres_fdw           | 1.0             |                   | foreign-data wrapper for remote PostgreSQL servers
...