Re: [TLS] A small detail in HMAC key generation for Finished message

2016-01-04 Thread Eric Rescorla
On Mon, Jan 4, 2016 at 4:11 PM, Martin Thomson wrote: > On 5 January 2016 at 05:03, Eric Rescorla wrote: > > Ask and ye shall receive: > http://tlswg.github.io/tls13-spec/#digital-signing > > > > "Following that padding is a context string used to disambiguate > signatures > > for different purp

Re: [TLS] A small detail in HMAC key generation for Finished message

2016-01-04 Thread Martin Thomson
On 5 January 2016 at 05:03, Eric Rescorla wrote: > Ask and ye shall receive: http://tlswg.github.io/tls13-spec/#digital-signing > > "Following that padding is a context string used to disambiguate signatures > for different purposes. > The context string will be specified whenever a digitally-sign

Re: [TLS] A small detail in HMAC key generation for Finished message

2016-01-04 Thread Eric Rescorla
On Mon, Jan 4, 2016 at 9:58 AM, Hubert Kario wrote: > On Monday 04 January 2016 09:44:57 Eric Rescorla wrote: > > On Mon, Jan 4, 2016 at 9:22 AM, Hubert Kario > wrote: > > > On Thursday 24 December 2015 01:04:59 Christian Huitema wrote: > > > > On Wednesday, December 23, 2015 3:05 PM, Eric Resco

Re: [TLS] A small detail in HMAC key generation for Finished message

2016-01-04 Thread Hubert Kario
On Monday 04 January 2016 09:44:57 Eric Rescorla wrote: > On Mon, Jan 4, 2016 at 9:22 AM, Hubert Kario wrote: > > On Thursday 24 December 2015 01:04:59 Christian Huitema wrote: > > > On Wednesday, December 23, 2015 3:05 PM, Eric Rescorla wrote: > > > >> Similarly, in the HKDF-Expand-Label, do we

Re: [TLS] A small detail in HMAC key generation for Finished message

2016-01-04 Thread Salz, Rich
> The idea is to make this prefix-free. I added it as an explicit byte but > would be ok with a different separator as long as we banned it from the > context strings. Perhaps explain that rationale in the doc? ___ TLS mailing list TLS@ietf.org https:/

Re: [TLS] A small detail in HMAC key generation for Finished message

2016-01-04 Thread Eric Rescorla
On Mon, Jan 4, 2016 at 9:22 AM, Hubert Kario wrote: > On Thursday 24 December 2015 01:04:59 Christian Huitema wrote: > > On Wednesday, December 23, 2015 3:05 PM, Eric Rescorla wrote: > > >> Similarly, in the HKDF-Expand-Label, do we assume a final null byte > > >> for the "label"?> > > > No. I wo

Re: [TLS] A small detail in HMAC key generation for Finished message

2016-01-04 Thread Hubert Kario
On Thursday 24 December 2015 01:04:59 Christian Huitema wrote: > On Wednesday, December 23, 2015 3:05 PM, Eric Rescorla wrote: > >> Similarly, in the HKDF-Expand-Label, do we assume a final null byte > >> for the "label"?> > > No. I wonder if we should instead add the '\0' explicitly in the > > 4.

Re: [TLS] A small detail in HMAC key generation for Finished message

2015-12-25 Thread Michael StJohns
On 12/23/2015 8:04 PM, Christian Huitema wrote: On Wednesday, December 23, 2015 3:05 PM, Eric Rescorla wrote: I wonder what the zero length string actually means. Is it a null-terminated string that would encode in binary as a one octet byte string of value 0, or an empty string that would enco

Re: [TLS] A small detail in HMAC key generation for Finished message

2015-12-23 Thread Christian Huitema
On Wednesday, December 23, 2015 3:05 PM, Eric Rescorla wrote: >> I wonder what the zero length string actually means. Is it a null-terminated >> string >> that would encode in binary as a one octet byte string of value 0, or an >> empty >> string that would encode in binary as a zero length str

Re: [TLS] A small detail in HMAC key generation for Finished message

2015-12-23 Thread Eric Rescorla
On Wed, Dec 23, 2015 at 2:19 PM, Christian Huitema wrote: > In the current 1.3 draft, section 6.3.4.3 specifies the content of the > Finished message. It contains this specification for key computation: > > client_finished_key = > HKDF-Expand-Label(BaseKey, "client finished", "", L) > > serve