Implement ed25519 HD keyring

[iov-one]

Implement ed25519 HD keyring

[ethanfrey]

These may be useful links:

• https://github.com/alepop/ed25519-hd-key
• https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
• (maybe) https://github.com/bitcoinjs/bip39

[will-iov]

I've used https://github.com/bitcoinjs/bip39 before: solid with some multi-language support.

[ethanfrey]

Builds upon #52

[webmaster128]

The signatures from the keys should be verifiable with the normal ed25519 keyring #23

Could you elaborate what you mean by that @ethanfrey? What use case do you have in mind here? Right now we have no concept of verifying other people's signatures in a Keyring

[ethanfrey]

At one point, I thought we would expose verify in a keyring, but this is done in @iov/crypto:Ed25519.

I guess you are just using the Slip0010 class to create a private key to feed into the above class, so of course the signatures should verify with the same class. I guess a proper rewording would just be:

"Verify that you can generate a key in this KeyRing, properly sign a message, and verify the signature with @iov/crypto:Ed25519 using the public key returned from the keyring. This serves mainly as an example of normal usage of the HD Keyring, as well as a sanity check."

Does that work? If so, I will update the issue text.

[webmaster128]

Thanks for clarification, this makes sense. Given that Slip0010 outputs private keys only, the rest is done using @iov/crypto:Ed25519 anyway. So the requested feature comes for free :)

[webmaster128]

Status: the heavy work is done. Just the proper derivation paths are missing

[ethanfrey]

Yeah, looks like 95% done, just a bit of polish.
But then, I am not 100% sure how the polish would look.
Maybe we can leave this as is and polish it when we have a concrete issue to use it with multiple chains