SRTP KDF errata should be supported

[RKinsey]

At least one major SRTP implementation, libSRTP, uses a KDF that is incorrect according to both SP 800-135 and the original RFC 3711 because it treats SRTP and SRTCP IVs identically (both specs say SRTCP's index should be 16 bits shorter, which moves the label position in the IV).

However, there has been errata issued for RFC 3711 that changes the KDF behavior to match libSRTP's. The amended KDF has been approved by NIST since 2016 (see: https://csrc.nist.gov/CSRC/media/Publications/sp/800-135/rev-1/final/documents/sp800-135r1-informative-note-20160919.pdf), but is still unsupported by both ACVTS and the legacy ASKDFVS.

[celic]

Thanks for the information. I'll make sure this gets included.

[livebe01]

The fix for this is on Demo in release v1.1.0.28.

[livebe01]

The fix for this is on Prod in release v1.1.0.28.