[rtcweb] Open Security issue: Crypto algorithms

[Harald Alvestrand <[e-mail]>]

security-arch-11 contains the following text:

    All implementations MUST implement DTLS 1.0, with the cipher suite
    TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA and the DTLS-SRTP protection
    profile SRTP_AES128_CM_HMAC_SHA1_80.  Implementations SHOULD
    implement DTLS 1.2 with the TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
    cipher suite.  Implementations SHOULD favor cipher suites which
    support PFS over non-PFS cipher suites and GCM over CBC cipher
    suites.  [[OPEN ISSUE: Should we require ECDSA?  Waiting for WG
    Consensus.]]


security-arch-10 contained the following text in the same spot:

    All implementations MUST implement both DTLS 1.2 and DTLS 1.0, with
    the cipher suites TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 and
    TLS_DHE_RSA_WITH_AES_128_CBC_SHA and the DTLS-SRTP protection profile
    SRTP_AES128_CM_HMAC_SHA1_80.  Implementations SHOULD favor cipher
    suites which support PFS over non-PFS cipher suites and GCM over CBC
    cipher suites.  [[OPEN ISSUE:  Should we require ECDHE?  Waiting for
    TLS WG Consensus.]]

So it seems that consensus has shifted from MUST for DHE_RSA to MUST for 
ECDHE_RSA (presumably based on a TLS WG consensus), with some arguing 
for inclusion of ECDSA in the mandatory ciphersuites, and has landed on 
DTLS 1.0 only being mandatory.

I tried to find the discussion in the archives, but failed - which makes 
it hard to have an opionion of where consensus is heading; there is a 
February note from Martin that's relevant, but that's all I found.

Minutes from last meetings are here:

https://tools.ietf.org/wg/rtcweb/minutes?item=minutes-92-rtcweb.html
https://tools.ietf.org/wg/rtcweb/minutes?item=minutes-91-rtcweb.html

I couldn't find anything relevant there either.

Do we have an idea on how to move forward with resolving the outstanding 
question?

(the trigger for the question is a colleague looking into the crypto 
code for our implementation; he would prefer to spend his time making 
sure the stuff we specify as mandatory works well.)

Harald