The transactions in blockchain framework, based cryptocurrencies are publicly available, thereby accessible to all users by design. However, the anonymity of blockchain transactions is necessary for acceptance of such frameworks. There is a need to preserve the privacy of the identities of the blockchain members and the transaction. The main challenge is that anonymity-provisioning mechanism must allow verification by other members for updating the blockchain. The pseudonymous attribute of most of the blockchain-based e-cash protocols is not sufficient for users to attain identity privacy and transaction privacy. This paper provides a comprehensive study of the threats and attacks that aim to deanonymize the e-cash protocols. We present a detailed survey of methods and protocols required for anonymity-provisioning of blockchain-based e-cash transactions. We discussed their features and limitations. We redefined anonymity on the blockchain and categorized the anonymity-provisioning methods and protocols with their outcomes. We provide guidelines for selecting an approach to design an anonymity-provisioning blockchain-based e-cash system. Furthermore, we provide directions for future research in anonymity-provisioning on blockchain-based e-cash protocols.

区块链框架中基于加密货币的交易是公开可用的，因此所有用户均可通过设计访问。但是，区块链交易的匿名性对于接受这样的框架是必要的。有必要保护区块链成员和交易身份的隐私。主要挑战在于，匿名供应机制必须允许其他成员进行验证以更新区块链。大多数基于区块链的电子现金协议的假名属性不足以使用户获得身份隐私和交易隐私。本文对旨在消除电子现金协议匿名性的威胁和攻击进行了全面研究。我们对基于区块链的电子现金交易进行匿名供应所需的方法和协议进行了详细调查。我们讨论了它们的功能和局限性。我们在区块链上重新定义了匿名性，并将匿名性提供方法和协议及其结果进行了分类。我们为选择一种设计基于匿名供应链的基于区块链的电子现金系统的方法提供了指导。此外，我们为基于区块链的电子现金协议的匿名提供未来的研究提供了指导。