# File lib/json/jwk/jwkizable.rb, line 26
        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