Delegation-Based Roaming Payment Protocol with Location and Purchasing Privacy Protection

We proposed a new delegation-based roaming payment protocol for portable communication systems (PCS), by leveraging the good performance of blind signature in the regard of user privacy, which can provide unlink ability between PCS and service providers. However, the ability to discover the malicious user´s identification is still remained. Home agents can detect the misbehavior and identify the mobile user if she/he doubly spends the e-cash in roaming. Due to the delegation-based authentication, the foreign agent can validate the communication without needing to reveal the real identity of the mobile user. Moreover, the computational cost can be reduced by using elliptic curve operations.