[Cryptography Team] Re: KryptOn MakoEnvelope signedAndSealedFrom:to:object:

[Chris Muller]

Hi Tony, it may very well be the other way around.  I
am honestly no encryption expert, just a skilled
implementor.  I will try to find the web reference
that recommended that.

As for ECB, I'm sorry I have no idea what that means. 
This is exactly the kind of critique I need your guys'
help with.  I am hoping that the usage and management
are mostly ok, but there may be some tightening needed
in the cryptography layer.

This is a very worthy discussioon for the cryptography
list, I hope you don't mind that I have copied that
list here.

Cheers,
  Chris

--- Tony Garnock-Jones <tonyg at lshift.net> wrote:

> Hi Chris,
> 
> In the comment to method MakoEnvelope
> class>>signedAndSealedFrom:to:object:, you write
> "Security experts
> recommend putting the signed inside the sealed".
> 
> Isn't it the other way around? According to
> http://www-cse.ucsd.edu/users/mihir/papers/oem.html
> the least insecure
> method is to encrypt, then MAC.
> 
> Also: On digging into the implementation of
> enciphering, it looks like
> the default cipher, Rijndael, is being used in ECB
> mode. Have I analysed
> that correctly? (If so, there are other modes that
> might be better: AEAD
> modes such as EAX or GGM; at a minimum, CTR, but an
> AEAD mode would be
> better, of course)
> 
> Regards,
>   Tony
> --
>  [][][] Tony Garnock-Jones     | Mob: +44 (0)7905
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