Compute Hashes With pgcrypto

The pgcrypto extension that comes with PostgreSQL adds access to some general hashing functions. Included are md5, sha1, sha224, sha256, sha384 and sha512. Any of these hashing functions can be applied to an arbitrary string using the digest function. Here are example of the md5 and sha1 algorithms:

> create extension pgcrypto;
CREATE EXTENSION

> select digest('Hello, World!', 'md5');
               digest
------------------------------------
 \x65a8e27d8879283831b664bd8b7f0ad4

> select digest('Hello, World!', 'sha1');
                   digest
--------------------------------------------
 \x0a0a9f2a6772942557ab5355d76af442f8f65e01

See the pgcrypto docs for more details.