ARCT: An Efficient Aggregating Ring Confidential Transaction Protocol in Blockchain

Anonymous cryptocurrency is a branch of cryptocurrency designed to protect users' privacy. Ring Confidential Transaction (RingCT) protocol is widely used in anonymous cryptocurrencies (e.g. Monero) to hide transaction information. However, its expensive computing and storage costs slow down the performance of the system. In this work, we propose a high-efficient RingCT protocol which is called aggregation ring confidential transaction (ARCT). In our protocol, we build a compact aggregation proof for multiple accounts of the sender, which enables our protocol to linearly shorten the signature size compared to other protocols. In addition, in order to further protect the privacy information, we first implement hiding the amount of the sender's accounts. Our protocol can provide cryptocurrencies with better privacy protection and lower resource cost. Besides, it does not require a trust setting. For a typical n=2 input transaction with the ring size of 128, the signature size of our protocol is 93% less than it used in the original protocol. ARCT build on the techniques of inner product optimization algorithm and cryptographic accumulators. We show that our underlying algorithm satisfies the security under the random oracle model.