AES128 or AES256 by default?

Simon Josefsson simon at
Thu May 15 11:34:50 CEST 2008

There is a debian bug:

Which asks that we make AES-256 the default preferred cipher.  Right now
AES-128 is the default preferred cipher.  Of course, today AES-256 is
supported as well (it is the second preferred default cipher).

What do people think here?

I don't care strongly, but I find the arguments for AES-256 rather weak.
According to RFC 3766, to match a 256 bit symmetric key size, you need a
~15kb large RSA key or a ~500b large DSA key.  People don't use that
kind of public key sizes today as far as I know, as they become very
big.  The few who do should be able to tweak the GnuTLS cipher
preference accordingly.


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