Public Key Infrastructure

title: bsvalias Public Key Infrastructure
authors:
  - andy (nChain)
  - Ryan X. Charles (Money Button)
version: 1

Each paymail handle <alias>@<domain>.<tld> MUST be issued a stable ECDSA public key that SHOULD NOT be used as part of any on-chain transaction. Clients must be able to locate the public key from information within the .well-known/bsvalias configuration file:

{
  "bsvalias": "1.0",
  "capabilities": {
    "pki": "https://bsvalias.example.org/{alias}@{domain.tld}/id",
  }
}

The template values {alias} and {domain.tld} refer to the components of target paymail handle <alias>@<domain>.<tld> and must be substituted by the client before issuing a request.

PKI Flow

boundary "Client" as c
control "Paymail Service" as svc

activate c
  c --> c: Service Discovery
  ...
  c -> svc: GET <PKI URI>
  activate svc
    svc -> c: 200; application/json
  deactivate svc
deactivate c

Client Request

The capabilities.pki path returns a URI template. Clients should replace the {alias} and {domain.tld} template parameters and then make an HTTP GET request against this URI.

Standard HTTP caching headers SHOULD be supported, and clients that have previously requested the public key SHOULD NOT re-request information within any server-advertised caching window.

Server Responses

Below are the responses that have meaning to this protocol. A server may return other status codes, for example 5xx indicating some sort of server failure. Clients should treat status codes not specified as part of this specification as some sort of transient error and may retry at their leisure.

200 OK

Returned when a valid request for a known paymail handle has been received. The return message MUST have a content type of application/json. The response body MUST conform to the following schema:

{
  "bsvalias": "1.0",
  "handle": "<alias>@<domain>.<tld>",
  "pubkey": "..."
}

The public key MUST be a valid point on the secp256k1 curve, compressed, and hex-encoded. This means that the pubkey string length MUST be 66 bytes long (33 bytes binary, each byte encoded as two hex characters):

Start	Length	Value
00	02	"Odd/even" indicator, must be either 02 or 03
02	64	Elliptic curve point x-coordinate

304 Not Modified

No public key rotation has taken place since the previous request, based on caching headers supplied.

404 Not Found

The paymail handle was not found by this service.