docs: def recoverPubkey(idText, cert, caPubkey):
      """
      A client can recover the server's pubkey using the identity string @idText,
      server's implicit @cert, and the trusted @caPubkey.
      """
      # Verify types
      assertType(cert, ec1Element)
      assertType(caPubkey, ec1Element)
  
      # Compute the pubkey
      return _exp(cert, idText)*cert + caPubkey