When the key exchnage is DHE, the server key exchange message contains the key paramteres: g^y (the server's public DHE value), g, p. Can you clarify to me what is the server key exchange content if the key exchange is ECDHE? What paramters are included there?
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TL;DR: The public key and the name of the group.
RFC 4492 (especially section 5.4) has all the details for you.
What you basically do is the following:
- You send a point on the curve (your public key, ie $Q=y\cdot G$)
- You send a description of the curve, this is either:
- Some identifier for the curve, for example
23if you wanted to use the most-commonly used P-256. This is what happens always in practice, in fact many browsers don't even support explicit curve parameters. - A full description of the prime or binary curve, ie the relevant values to define the field, the relevant values to define the curve parameters over the field and the relevat base point.
