DEMOS-2: Scalable E2E Verifiable Elections without Random Oracles
DEMOS-2: Scalable E2E Verifiable Elections without Random Oracles
复制标题
DEMOS-2：无需随机预言的可扩展端到端可验证选举
DOI：
10.1145/2810103.2813727
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Bingsheng Zhang
中科院分区：
文献类型：
--
作者：
A. Kiayias;T. Zacharias;Bingsheng Zhang
最近，Kiayias，Zacharias和Zhang提出了一种新的E2 E可验证的电子投票系统，称为“DEMOS”，首次提供E2 E可验证性，而不依赖于外部随机源或随机预言模型;这种系统的主要优点是选举审计员只需要选举成绩单和选民的反馈就可以明确宣布选举过程有效。不幸的是，与Helios等其他电子投票系统相比，DEMOS对选举机构（EA）的性能和存储造成了巨大的损失。主要原因是，由于EA形成计票结果证明的方式，它需要为每个投票者和投票者的每个可能选择预先计算一些密文。这种方法显然不适用于选票复杂的选举，选民在候选人数量上有指数级的投票方式。EA上的性能惩罚似乎是这种方法所固有的：投票者不能自己计算一个加密选票，因为他们似乎没有办法证明它是一个有效的密文。与上述相比，在这项工作中，我们构建了一个新的电子投票系统，保留了强大的E2 E特性的DEMOS（但对计算对手），同时完全消除了性能和存储惩罚的EA。我们通过一种新的加密构造来实现这一点，该构造使EA使用选民的硬币产生并证明公共参考字符串（CRS）的安全性，选民随后可以使用该公共参考字符串将非交互式零知识（NIZK）证明附加到他们的密文中。EA本身使用CRS通过NIZK证明最后的计数正确性。我们的结构具有类似的性能，太阳神和实用。我们的构造的隐私依赖于通过复杂性杠杆作用在双线性群上的SXDH假设。
Recently, Kiayias, Zacharias and Zhang-proposed a new E2E verifiable e-voting system called 'DEMOS' that for the first time provides E2E verifiability without relying on external sources of randomness or the random oracle model; the main advantage of such system is in the fact that election auditors need only the election transcript and the feedback from the voters to pronounce the election process unequivocally valid. Unfortunately, DEMOS comes with a huge performance and storage penalty for the election authority (EA) compared to other e-voting systems such as Helios. The main reason is that due to the way the EA forms the proof of the tally result, it is required to {\em precompute} a number of ciphertexts for each voter and each possible choice of the voter. This approach clearly does not scale to elections that have a complex ballot and voters have an exponential number of ways to vote in the number of candidates. The performance penalty on the EA appears to be intrinsic to the approach: voters cannot compute an enciphered ballot themselves because there seems to be no way for them to prove that it is a valid ciphertext. In contrast to the above, in this work, we construct a new e-voting system that retains the strong E2E characteristics of DEMOS (but against computational adversaries) while completely eliminating the performance and storage penalty of the EA. We achieve this via a new cryptographic construction that has the EA produce and prove, using voters' coins, the security of a common reference string (CRS) that voters subsequently can use to affix non-interactive zero-knowledge (NIZK) proofs to their ciphertexts. The EA itself uses the CRS to prove via a NIZK the tally correctness at the end. Our construction has similar performance to Helios and is practical. The privacy of our construction relies on the SXDH assumption over bilinear groups via complexity leveraging.