Re: TripleDES output size

On 5 Oct 2006 23:28:53 -0700, "Valery Pryamikov" <valery@xxxxxxxxx>
wrote:

Thanks for your reply but it doesn't help me.

I mean. Let's say I've a 5 chars string I want to encrypt.
Encrypting it using .NET framewirk TripleDESCryptoServiceProvider
gives me a string of 24 chars lenght.
Now how can I calculate the length of the crypted string based on the
size of the plain one?

Thanks.

HI,
3DES has 8 bytes (64 bits) block size.
if you use it with default CBC mode of encryption, the last block is
always padded to make it a full block. In case if plain text size is
exact multiple of 8 bytes, then the whole block of padding is added.

-Valery.
http://www.harper.no/valery

Arturo Buonanni wrote:
Hello to all,

I'm new to cryptography and I've to implement encryption of data into
a database.
I'm using .NET framework TripleDESCryptoServiceProvider to crypt and
decrypt strings.
Anyway I can not find any reference on how to calculate the length of
the encrypted string based on the length of the plain string.
As I've to store the encrypted data into table fields, I've to be sure
it fits into the field size.

Does anybody knows how to do this?

Thanks.
(I'm posting this also to microsoft.public.security.crypto)
.

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