[WG-IMS] IMS Authentication Scheme

[Răzvan Crainea]

Hello, Everyone!

According to the latest ETSI specifications [1], IMS supports the 
following authentication schemes:
* Digest-AKAv1-MD5 / Digest-AKAv2-SHA-256
* SIP Digest
* NASS-Bundled
* Early-IMS-Security

We already support SIP Digest, and as far as I know the most widely used 
one is the AKAv1 authentication, thus this is our main focus now. 
However, I was wondering whether the other ones are still in use (i.e. 
phones still supports them), or they have been completely dropped, 
either by phones, either by the OS they are running on. We were 
basically trying to figure out whether we should be focusing on 
implementing them as well, or they have been somehow obsoleted and 
nowadays most of the phones do support AKA/SIP Digest.

[1] 
https://www.etsi.org/deliver/etsi_ts/129200_129299/129229/17.02.00_60/ts_129229v170200p.pdf

Looking forward for your feedback!

-- 
Răzvan Crainea
OpenSIPS Core Developer / SIPhub CTO
http://www.opensips-solutions.com / https://www.siphub.com