A privacy preserving two-factor authentication protocol for the Bitcoin SPV nodes

Abstract

In the Bitcoin network, the simplified payment verification protocol (SPV) enables a lightweight device such as a mobile phone to participate in the bitcoin network without needed to download and store the whole Bitcoin blocks. A Bitcoin SPV node initiates and verifies transactions of the Bitcoin network through the Bitcoin wallet software which is deployed on a resource constrained device such as a mobile phone. Thus, the security of the wallet is critical for the SPV nodes as it may affect the security of user's cryptocurrencies. However, there are some concerns about the security flaws within the SPV nodes which could lead to significant economic losses. Most of these vulnerabilities can be resolved by employing a secure user authentication protocol. Over the years, researchers have engaged in designing a secure authentication protocol. However, most proposals have security flaws or performance issues. Recently, Park et al. proposed a two-party authenticated key exchange protocol for the mobile environment. They claimed that their protocol is not only secure against various attacks but also can be deployed efficiently. However, after a thorough security analysis, we find that the Park et al.'s protocol is vulnerable to user forgery attack, smart card stolen attack and unable to provide user anonymity. To enhance security, we proposed an efficient and secure user authentication protocol for the SPV nodes in the mobile environment which can fulfill all the security requirements and has provable security. Additionally, we provide performance analysis which shows our proposed protocol is efficient for the SPV nodes in the Bitcoin network.

A Privacy Protection Method of Lightweight Nodes in Blockchain

“…Le et al [44] propose a two-tree oblivious random access memory (ORAM) construction to protect SPV clients' requests from a potentially malicious server. Zhou et al [45] proposed a privacy-preserving two-factor user authentication protocol for the SPV nodes in the Bitcoin network that meets all the security requirements and has provable security.…”