Recent work introduces zkay, a system for specifying and enforcing data privacy in smart contracts. While the original prototype implementation of zkay (v0.1) demonstrates the feasibility of the approach, its proof-of-concept implementation suffers from severe limitations such as insecure encryption and lack of important language features. In this report, we present zkay v0.2, which addresses its predecessor's limitations. The new implementation significantly improves security, usability, modularity, and performance of the system. In particular, zkay v0.2 supports state-of-the-art asymmetric and hybrid encryption, introduces many new language features (such as function calls, private control flow, and extended type support), allows for different zk-SNARKs backends, and reduces both compilation time and on-chain costs.

中文翻译：

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zkay v0.2：智能合约的实用数据隐私

最近的工作介绍了 zkay，这是一个用于在智能合约中指定和执行数据隐私的系统。虽然 zkay (v0.1) 的原始原型实现证明了该方法的可行性，但其概念验证实现受到严重限制，例如不安全的加密和缺乏重要的语言特性。在本报告中，我们介绍了 zkay v0.2，它解决了其前身的局限性。新的实施显着提高了系统的安全性、可用性、模块化和性能。特别是，zkay v0.2 支持最先进的非对称和混合加密，引入了许多新的语言特性（例如函数调用、私有控制流和扩展类型支持），允许使用不同的 zk-SNARKs 后端，以及减少编译时间和链上成本。