Imports System.Security.Cryptography

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Guest

I am trying to write an un-managed implementation of the Rijndael alogrithm to access a file encrypted through the RijndaelManaged class. I know the key and Initial vector passed in to the CreateEncryptor method but every impementation of the algorithm I come across has no provision for an Initial Vector parameter.
 
Hello,

Based on my understanding, currently you are asking for some information on
the implementation of Rijndael alogrithm, right?

One good resource on this topic is
http://fp.gladman.plus.com/cryptography_technology/rijndael/, which
provides Algorithm Specification and Algorithm Code in C/C++. It also
includes many code samples. I feel it should be helpful for you.

If you feel there is any we can do for you, please feel free to post here.
Thanks very much.

Best regards,
Yanhong Huang
Microsoft Community Support

Get Secure! ¨C www.microsoft.com/security
This posting is provided "AS IS" with no warranties, and confers no rights.
 
I already have several basic implementation samples of the alogrithm
including the implementation from the link you referenced, but none of
them use a user supplied Initial Vector.
 
Hello Vincent,

I am not familar with the internal implementation of Rijndael alogrithm.
Just now, I quickly go through the specs in that web site and didn't find
any evident IV implementation in it.

However, I found some info in Internet:

[From the CipherMode docs]
"The Cipher Block Chaining (CBC) mode introduces feedback. Before each
plain text block is encrypted, it is combined with the cipher text of the
previous
block by a bitwise exclusive OR operation. This ensures that even if the
plain text contains many identical blocks, they will each encrypt to a
different cipher text block. The initialization vector is combined with the
first plain text block by a bitwise exclusive OR operation before the block
is encrypted."

That is exactly what the IV is for :-)

For more information on it, please refer to this google link:
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&threadm=eSwCq7sC
DHA.2704%40TK2MSFTNGP11.phx.gbl&rnum=8&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3
DUTF-8%26oe%3DUTF-8%26q%3Dinitialization%2Bvector%2BRijndaelManaged%26sa%3DN
%26tab%3Dwg

Hope that help.

Best regards,
Yanhong Huang
Microsoft Community Support

Get Secure! ¨C www.microsoft.com/security
This posting is provided "AS IS" with no warranties, and confers no rights.
 
Hi Vincent,

Do you have any more concerns on the message that I posted? If there is any
we can do for you, please feel free to post here. I am glad to be of
assistance.

Thanks.

Best regards,
Yanhong Huang
Microsoft Community Support

Get Secure! ¨C www.microsoft.com/security
This posting is provided "AS IS" with no warranties, and confers no rights.
 
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