Use coincurve instead of secp256k1-py

[czepluch]

Problem Definition

It seems that secp256k1-py is not being maintained anymore and that http://github.com/ofek/coincurve are maintaining a library instead.

Solution

Use http://github.com/ofek/coincurve instead of secp256k1-py
This should also remove the annoying warning from secp256k1-py when starting raiden.

[hrishikeshio]

I got functions for keys, sign and address converted to use coincurve.
Recover function does not seem to work work in coincurve as of latest version.
ofek/coincurve#1

[hrishikeshio]

Also, this: https://github.com/ofek/coincurve/blob/master/coincurve/ecdsa.py#L32

[ofek]

@czepluch @hrishikeshio Thanks for the interest in coincurve!

I've made the recovery workflow much easier in 4.2.0 by adding PublicKey.from_signature_and_message. Travis should be finished the deploy in less than an hour.

[hrishikeshio]

@ofek Thanks alot but now I am having a different issue. This function worked in earlier version.
ofek/coincurve#2

@czepluch Perhaps we should keep secp256k1.py for now and use coincurve later once it is more matured.
Also ethereum.py is using secp256k1.py so it is not easy to remove dependency on secp256k1.py completely.

[ofek]

Coincurve is stable!

@hrishikeshio You seem to be using coincurve as a drop-in replacement for secp256k1-py. This will cause issues because the 2 don't share the same API. Coincurve has an API that is MUCH easier to use. I've documented it here: https://github.com/ofek/coincurve#readme.

[czepluch]

@hrishikeshio Just make a PR for pyethereum changin to coincurve aswell.

[ofek]

@czepluch ethereum/pyethereum#708 :)

[czepluch]

Ah, excellent :) Thanks.