Re: feedback requested regarding deprecation of TLS 1.0/1.1

[Jacob Bachmeyer <jcb62281 () gmail com>]

Hanno Böck wrote:
> Hello,
>
> I have no particular insight on the prevalence of TLS 1.0/1.1 these
> days, but I want to make a more general comment.
> My impression of OpenSSL is that it has a strong tendency to ship
> "bloat", i.e., features that either barely anyone needs, but that still
> get added (remember Heartbeat extension?), or that should've been
> deprecated long ago.
>
> If this effort to deprecate old protocols is a sign that this is
> changing, I welcome this. I'd recommend to have a look at other things
> in the OpenSSL codebase that should be trimmed.
>   

That actually raises another question:  what is actually to be gained 
from deprecating TLS1.0/1.1?  Did the protocol significantly change or 
is the only major difference new cipher suites?

In other words, what non-trivial code paths would dropping TLS1.0/1.1 
entirely allow removing?  (Concatenating SHA1+MD5 is trivial.)

> I also think there's probably potential to remove some obsolete
> ciphers (DSA?).

While DSA is definitely obsolete (advances in conventional computing 
have begun to approach the ability to plausibly solve 1024-bit keys, and 
DSA keys *MUST* be 1024-bit, supposedly to facilitate smartcard 
implementations), OpenSSL is also a general cryptographic library and 
applications can use its primitives for other purposes.  In particular, 
this means that dropping TLS1.0/1.1 cipher suites does *not* mean you 
can drop the ciphers that were used in those suites.



-- Jacob