Public Accountability vs. Secret Laws: Can They Coexist?: A Cryptographic Proposal
Public Accountability vs. Secret Laws: Can They Coexist?: A Cryptographic Proposal
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公共责任与秘密法律：它们可以共存吗？：密码学提案
DOI：
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发表时间：
2017
期刊：
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通讯作者：
Sunoo Park
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作者：
S. Goldwasser;Sunoo Park
“我们的法律并不广为人知；它们被统治我们的一小群贵族保守着秘密。我们确信这些古老的法律得到了严格的执行；然而，被一个人不知道的法律统治是一件极其痛苦的事情。”——弗朗茨·卡夫卡，《寓言与悖论》。 9/11 事件后，记者、学者和活动人士指出，由于对国家安全的担忧日益加剧，美国政府所有三个部门的秘密法律——其细节和有时仅仅存在就被列为绝密的法律体系——正在增加。当前关于政府希望对加密数字数据进行特殊访问的激烈争论中，关键问题之一是：可以建立哪些机制来确保政府机构以不损害国家安全目标的方式遵循商定的规则？当授予加密数据访问权限的规则本身可能是秘密的时，这将尤其具有挑战性。在这项工作中，我们展示了如何使用加密协议，特别是零知识证明的想法，可以在这种非同寻常的、看似陷入僵局的环境中确保政府的问责制和透明度。我们提出了一种高效的记录保存基础设施，具有多功能的可公开验证的审计，可以保护记录内容的（信息论）隐私以及记录被证明遵守的规则。我们的协议基于现有的区块链和加密工具，包括承诺和零知识SNARK，并满足不可删除（即无回溯）、完美的数据隐私、秘密数据的公开可审计性、可问责的删除和简洁性等特性。我们还提出了一种变体方案，可以要求实体根据记录内容（例如，违反规定）支付费用，同时仍然保护隐私。我们的方案可以直接在以太坊区块链上实例化（而保证较弱的简化版本可以用比特币实例化）。
"Our Laws are not generally known; they are kept secret by the small group of nobles who rule us. We are convinced that these ancient laws are scrupulously administered; nevertheless it is an extremely painful thing to be ruled by laws that one does not know."--Franz Kafka, Parables and Paradoxes. Post 9/11, journalists, scholars and activists have pointed out that it secret laws - a body of law whose details and sometime mere existence is classified as top secret - were on the rise in all three branches of the US government due to growing national security concerns. Amid heated current debates on governmental wishes for exceptional access to encrypted digital data, one of the key issues is: which mechanisms can be put in place to ensure that government agencies follow agreed-upon rules in a manner which does not compromise national security objectives? This promises to be especially challenging when the rules, according to which access to encrypted data is granted, may themselves be secret. In this work we show how the use of cryptographic protocols, and in particular, the idea of zero knowledge proofs can ensure accountability and transperancy of the government in this extraordinary, seemingly deadlocked, setting. We propose an efficient record-keeping infrastructure with versatile publicly verifiable audits that preserve (information-theoretic) privacy of record contents as well as of the rules by which the records are attested to abide. Our protocol is based on existing blockchain and cryptographic tools including commitments and zero-knowledge SNARKs, and satisfies the properties of indelibility (i.e., no back-dating), perfect data privacy, public auditability of secret data with secret laws, accountable deletion, and succinctness. We also propose a variant scheme where entities can be required to pay fees based on record contents (e.g., for violating regulations) while still preserving privacy. Our scheme can be directly instantiated on the Ethereum blockchain (and a simplified version with weaker guarantees can be instantiated with Bitcoin).