[ADMIN] How To Change Password Hash Algorithm From MD5 to SHA-256

[ROMAIN, ERICKA W CTR DISA PEO-MA]

I am trying to get Postgres to use SHA as the password hash algorithm instead 
of MD5. This is a security requirement. I am running PostgreSQL 8.4 on a Red 
Hat Linux platform. I have installed pgcrypto and ran pgcrypto.sql. I also 
created a function SHA-256. The function looks like:

CREATE OR REPLACE FUNCTION sha256(bytea) returns text AS $$
      SELECT encode(digest($1, 'sha256'), 'hex')
    $$ LANGUAGE SQL STRICT IMMUTABLE;

I then created a new user. Then I queried pg_shadow and the encrypted password 
still has md5 at the beginning of the hash. How do I get postgres to use 
SHA-256?

Any help would be greatly appreciated.


Ericka Romain

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