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@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 974 211 [][] LShift Ltd | Tel: +44 (0)20 7729 7060 [] [] http://www.lshift.net/ | Email: tonyg@lshift.net