Re: 128 bit block ciphers

[Uri Blumenthal <uri@xxxxxxxxxxxxxx>]

Werner Koch says:
> How does OpenPGP cope with 128 bit block ciphers (AES)?
>    The data is encrypted in CFB mode, with a CFB shift size equal to
>    the cipher's block size.  The Initial Vector (IV) is specified as
>    all zeros.  Instead of using an IV, OpenPGP prefixes a 10-octet
>    string to the data before it is encrypted.  The first eight octets
>    are random, and the 9th and 10th octets are copies of the 7th and
> Wouldn't it be better to prefix it with 16 random bytes for 128 bit
> ciphers?  Maybe we can remove the special CFB mode for these ciphers?

Yes, it would be better to follow your propossal.
-- 
Regards,
Uri		uri@xxxxxxxxxxxxxx
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