[Pycrypto-checkins] [ pycrypto-Bugs-1559789 ] AES MODE_CBC require multiple of 16 bytes to work?

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Bugs item #1559789, was opened at 2006-09-16 08:11
Message generated for change (Comment added) made by nobody
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: AES MODE_CBC require multiple of 16 bytes to work?

Initial Comment:
It seems to me that the CBC algorithm is implemented a 
little odd...

When using the CBC mode it should be possible to pass 
data with lengths not a multiple of 16?

The following code produces the error:

from Crypto.Cipher import AES

a = AES.new('abcdefghabcdefgh', AES.MODE_CBC)
a.encrypt('This is a test    ')



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Comment By: Nobody/Anonymous (nobody)
Date: 2007-06-08 02:12

Message:
Logged In: NO 

You're right, this is not a bug.

I was not thinking about CFB, I was thinking about CTS. I was still wrong
though.

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Comment By: Dobes V (dobesv)
Date: 2007-05-01 14:56

Message:
Logged In: YES 
user_id=400635
Originator: NO

For CBC, there's no standard padding scheme and the algorithm requires
that you encrypt an even block in length.

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Comment By: Dobes V (dobesv)
Date: 2007-01-12 13:06

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user_id=400635
Originator: NO

Actually, no.  With CBC each block is XOR'ed with the next, one complete
block at a time.

You're probably thinking of CFB.


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