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

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.

-- 
Jonathan Leffler                   #include <disclaimer.h>
Email: jleffler_at_earthlink.net, jleffler_at_us.ibm.com
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