Please use other for secp256k1

[mattn]

Current implementation use github.com/ipsn/go-secp256k1 to marshal keys for secp256k1. But go-secp256k1 is cgo module. It is bits hard to publish binary executables which use go-did. Do you have plan to use other?

[mattn]

There are some candidates.

• https://github.com/dustinxie/ecc
• https://github.com/GincoInc/go-crypto
• https://github.com/ethereum/go-ethereum

[mattn]

@whyrusleeping What do you think?

[ericvolp12]

FYI I was updating a bunch of my deps today and realized I depend on https://github.com/decred/dcrd/tree/master/dcrec/secp256k1 which might provide what we need for this?

It's pure go and Copyfree licensed.