Anonymous Asynchronous Payment Channel from k-Time Accountable Assertion

Abstract

Accountable assertion enables a payer to make off-chain payments to a payee, and at the same time, the payer’s secret credentials can be revealed if she equivocates (i.e., makes conflicting statements to others). In this paper, we introduce a new construction of accountable assertion that allows an assertion to be accountable for k times. We also present a new construction of anonymous payment channels for the cryptocurrency Bitcoin that allows a payer with k-time accountable assertions to anonymously make off-chain payments to the payee. In particular, we define formal security models for the new constructions, we also prove that the k-time assertion can achieve strong secrecy, and the asynchronous payment channel can achieve anonymity and untraceability. The proposed anonymous payment channel with k-time accountable assertions ensures that: (1) the payee can anonymously receive funds at asynchronous points of sale, and (2) the payee can trace the real identities of payers when they equivocate, and penalize them afterward.