  Recent results have shown the usefulness of tamper-proof hardware tokens as a
setup assumption for building UC-secure two-party computation protocols, thus
providing broad security guarantees and allowing the use of such protocols as
buildings blocks in the modular design of complex cryptography protocols. All
these works have in common that they assume the tokens to be completely
isolated from their creator, but this is a strong assumption. In this work we
investigate the feasibility of cryptographic protocols in the setting where the
isolation of the hardware token is weakened.
  We consider two cases: (1) the token can relay messages to its creator, or
(2) the creator can send messages to the token after it is sent to the
receiver. We provide a detailed characterization for both settings, presenting
both impossibilities and information-theoretically secure solutions.
