Re: [IPsec] I-D on Using the ECC Brainpool Curves for IKEv2 Key Exchange

[Andrey Jivsov <[e-mail]>]

Sorry for bringing up this so late, but I just noticed the discussion 
about the point compression in this thread.

I posted the "Compact representation of an elliptic curve point" 
http://tools.ietf.org/html/draft-jivsov-ecc-compact that I think is 
helpful as a generic definition of a compressed point.

I know that 
https://datatracker.ietf.org/doc/draft-merkle-ikev2-ke-brainpool/ -03 
moved away from the compressed representation, but the preceding 
discussion is one of the reasons why I created this draft. It's 
unfortunate that with current state of ECC at IETF there is always an 
uncertainty/complexity such as "do we use an uncompressed point or 
compressed point; and there is IPR". There is also an issue of what's 
hashed and how the {x,y} is encoded. In the end in practice this means 
that there is no compression used.

I want to add as an alternative point of view that for new features or 
protocols there is also a way to reduce complexity by using only the 
compact point representation, such as in 
http://tools.ietf.org/html/draft-jivsov-ecc-compact.