Thank You; How Many VarBinary for each Ascii Char Aes Encrypted KeySize=256,BlockSize=256

From: Phil C. (charlestek_at_rcn.com)
Date: 02/25/05 

Date: Fri, 25 Feb 2005 10:10:49 -0500

Joe,

Thanks again for the detailed advice.
VarBinary seems also somewhat nebulous to me, as the definition I get from
Robert Viera's
Sql Server 2000 Programming Book says:
"Size in Bytes: 'Varies' ", "Variable length binary data with a maximum
length of
8,000 bytes."

So lets say I use UTF8, for 50 ascii characters I would expect 50 bytes, and
from the above VarBinary
definition, this implies that I could get away with the database column as
VarBinary 1 ???

Phil

"Joe Kaplan (MVP - ADSI)" <joseph.e.kaplan@removethis.accenture.com> wrote
in message news:uElSEj0GFHA.1172@TK2MSFTNGP12.phx.gbl...
> I'd suggest the best thing to do would be to try it out and see. AES uses
> padding backed on the block size, so you should get consistent sizes back.
> Assuming you are using UTF8 encoding to convert your plain text to a byte
> array for encryption, you could potentially get variable sizes of input
> data, but if all of the characters you are encoding are ASCII, then that
> should be consistent as well.
>
> You might also consider converting your encrypted data to Base64 to store
> in the db. That might be easier to deal with than storing as raw binary.
> It will be 4/3 the size of the original byte array, but then you can just
> use varchar.
>
> Joe K.
>
> "Phil C." <charlestek@rcn.com> wrote in message
> news:OHdnoOsGFHA.3916@TK2MSFTNGP12.phx.gbl...
>> Hi. I'm wanting to encrypt customer name, address, etc. information
>> using Aes with a KeySize of 256 and a BlockSize of 256. Either for each
>> ascii character or say for a maximum length 50 characters for a field,
>> how many bytes will this generate and how do I translate
>> this into the number of VarBinary ???items that I allocate in my Sql
>> Server 2000 table??
>>
>> Phil
>> Boston, MA
>>
>
>