Re: Oracle 10g R2 and TDE - change in space used?

Jonathan Leffler wrote:
> I've probably just not found the correct manual to read, but I looked in
> both the SQL Reference and the Advanced Security Guide and haven't found
> any information on the amount of extra space used if you're using TDE -
> transparent data encryption. Does each row (field?) grow, or is the
> extra key-related data stored somewhere else? For unsalted columns, it
> is conceivable that there is no growth; I fail to see how you can add
> salt to the encryption and not increase the storage a bit (enough for
> the salt, at least).
>
> Any pointers to where to look for the information would be gratefully
> received.

It is really a question of the number of bytes that will be stored by the algorithm you choose.

Look at the DBMS_CRYPTO built-in package (demos at www.psoug.org, Morgan's Library) and you will see an easy way to test out your largest string with your selected hash function, mac function, block cipher, chaining modifier, and padding modifier. They will all be different.

-- 
Daniel A. Morgan
http://www.psoug.org
damorgan_at_x.washington.edu
(replace x with u to respond)