Polymerized RingCT: An Efficient Linkable Ring Signature for Ring Confidential Transactions in Blockchain

Abstract

In this work, we study and refer the privacy protection protocol used in the blockchain, in particular, the Ring Confidential Transaction protocol in current popular anonymous cryptocurrency Monero. Based on our observations on the underlying linkable ring signature and homomorphic commitment schemes, we design a new efficient RingCT protocol for protecting user’s transaction information. Our scheme is built on the Schnorr ring signature, the well-known Pedersen commitment and signature of knowledge. We show that the signature algorithm used in our scheme satisfies the security requirements under random oracle model and adaptive chosen message attack. Moreover, compared with other ring confidential transactions protocols, our scheme can significantly save the cost of operation and interaction linearly under multi-account operation, that is, unlike other schemes, the cost of its underlying signature algorithm doesn't grow linearly as the spender’s accounts grow.