VeloCash: Anonymous Decentralized Probabilistic Micropayments With Transferability
Taisei Takahashi, Taishi Higuchi, Akira Otsuka · IEEE Access · 2022
Micropayments are one of the challenges in cryptocurrencies. Micropayments on the blockchain have the problem that the fee is high for the transfer amount. As a countermeasure, a method called Layer-two has been proposed to consolidate transactions outside the blockchain and improve the blockchain’s throughput. As one of the existing Layer-two schemes, Decentralized Probabilistic Micropayments have been proposed. The winning amount is registered in the blockchain, and the lottery tickets are issued to be won with probability$p$, which allows us to aggregate approximately$(1/p)$transactions into one. Unfortunately, existing solutions do not allow for ticket transferability, and the smaller$p$, the more difficult it is to use them in the real world. Here we propose$\textsf {VeloCash}$, Decentralized Probabilistic Micropayments with Transferability, which preserves anonymity. By introducing tamper-proof assumptions for sending and receiving the tickets, we make$p$smaller. As a tamper-proof hardware assumption,$\textsf {VeloCash}$uses Attested Execution Secure Processors, a formal abstraction of secure processors with attested execution functionality and Direct Anonymous Attestation to achieve anonymity for sending and receiving tickets.$\textsf {VeloCash}$can detect double-spending attacks perfectly and revoke the adversary’s device.