webauthn key & signature type

[spoonincode]

Finish adding webauthn key & signatures to eosio. There are still some unresolved questions (now solved; answers in bold) that came out of the prototype:

• where/how/if credential ID is stored - will not be stored as part of consensus; public storage discouraged regardless
• JSON parsing vs not parsing - We need to parse JSON, the "tricks" we discussed internally will not work due to item 4 on this list
• Compression of JSON or not - No
• Validation of HTTPS origin in signature or not (a public key would have an origin it is scoped to) - Yes we need to validate this
• Validation of user presence and/or user verification in signature (a public key would state some minimum level of verification requirement) - Doing this and maintaining the "symmetry" of recovered keys to the public keys in the authority is unwieldy, but it's probably useful to have this ability so will do it

Ideally all of these are answered before commencing work on the production implementation.

[jafri]

If credential ID is not stored as part of consensus or public storage, how will credentials be synced between nodes?

[spoonincode]

If credential ID is not stored as part of consensus or public storage, how will credentials be synced between nodes?

The public key that a credential ID references is part of consensus. It will be a PUB_WA_... thing. But the storage of the credential ID that is required to sign via the private key associated with that public key is left outside the scope of consensus.

[nksanthosh]

EOSJS related changes will be tracked in EOSIO/eosjs#537

[spoonincode]

#7421