TLS 1.2 with standard signature? Why hash->size == 36??

Carolin Latze carolin.latze at
Thu Oct 8 11:16:11 CEST 2009

Hi Simon,

I tried to use TLS 1.2 with and without sign callback, and I still see a
signature of 36 bytes... Even if there is a leading SHA-1 OID, shouldn't
it be max 35 then? Maybe we should check, whether I check the right

In gnutls_sig.c, method _gnutls_tls_sign_hdata, there is a structure
called dconcat. dconcat.size holds the hash size, right? and should hold the hash itself? dconcat.size has a value of 36
for me...

If I use the sign callback, I print the value of hash->size (=36) and
hash->data (cannot see the OID included in that value, so for me it
looks like it is really not SHA-1 only).

Maybe I check the wrong values?

BTW: I used the latest Snapshot, 2.9.8 to test it.

Sorry... :-/

Simon Josefsson wrote:
> Carolin Latze <carolin.latze at> writes:
>> Hi all,
>> according to RFC 5246, TLS 1.2 should use a standard signature, but if
>> I enable TLS 1.2 in GnuTLS and print out the hash size it says
>> 36... that does not sound like a standard signature.. I would expect
>> something like 20 for SHA1. Am I wrong?
> Hi!  With GnuTLS 2.9.7 I hope this should work better -- could you take
> a look?  It should have more solid TLS 1.2 support.
> Thanks,
> Simon

Carolin Latze
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