On Anonymity with Identity Escrow

摘要

Anonymity with identity escrow attempts to allow users of a service to remain anonymous, while providing the possibility that the service owner can break the anonymity in exceptional circumstances, such as to assist in a criminal investigation. A protocol for achieving anonymity with identity escrow has been presented by Marshall and Molina-Jiminez. In this paper, we show that that protocol suffers from some serious flaws. We also identify some other less significant weaknesses of the protocol, and we present an improved protocol which fixes these flaws. Our improved protocol guarantees anonymity even if all but one of the escrow holders are corrupt.