module JSON::JWK::JWKizable::EC

def to_jwk(ex_params = {})
  params = {
    kty: :EC,
    crv: curve_name,
    x: Base64.urlsafe_encode64([coordinates[:x]].pack('H*'), padding: false),
    y: Base64.urlsafe_encode64([coordinates[:y]].pack('H*'), padding: false)
  }.merge ex_params
  params[:d] = Base64.urlsafe_encode64([coordinates[:d]].pack('H*'), padding: false) if private_key?
  JWK.new params
end