Message-ID: <4664983F.4010700@burntmail.com>
Date: Mon, 04 Jun 2007 18:54:55 -0400
From: Guy Rouillier <guyr-ml1@burntmail.com>
User-Agent: Thunderbird 2.0.0.0 (Windows/20070326)
MIME-Version: 1.0
To: pgsql-general@postgresql.org
Subject: Re: Encrypted column
References: <46645B01.6070605@terra.com.br>
In-Reply-To: <46645B01.6070605@terra.com.br>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Ranieri Mazili wrote:
> Hello,
> 
> I need to store users and passwords on a table and I want to store it 
> encrypted, but I don't found documentation about it, how can I create a 
> table with columns "user" and "password" with column "password" 
> encrypted and how can I check if "user" and "password" are correct using 
> a sql query ?

Many people consider two-way encryption to be insecure; two-way 
encryption means you can decrypt a value if you know the key, and it is 
insecure because you usually have to put the key into the source code. 
That means at least one person in your company, the programmer 
maintaining the source code, can learn all of your users' passwords. 
One way around that is to hash the value instead.  Then to validate, at 
runtime you hash the user-entered password using the same hash function, 
and validate that it matches the stored hash.  No one in your company 
ever knows end-user passwords.

-- 
Guy Rouillier