论文标题
与密码学连接的转变局部保留景点
Locality-Preserving Hashing for Shifts with Connections to Cryptography
论文作者
论文摘要
我们能否通过占领周围环境样本来感知我们在不熟悉的环境中的位置?我们可以有效地加密只有一个人身体亲密的消息才能解密的消息吗?为了解决这种问题,我们介绍和研究一种新型的哈希功能,以查找均方根时间的变化。 A function $h:\{0,1\}^n\to \mathbb{Z}_n$ is a $(d,δ)$ {\em locality-preserving hash function for shifts} (LPHS) if: (1) $h$ can be computed by (adaptively) querying $d$ bits of its input, and (2) $\Pr [ h(x) \neq h(x \ ll 1) + 1] \leqδ$,其中$ x $是随机的,$ \ ll 1 $表示循环移动的左侧位。我们做出以下贡献。 *通过分布式离散日志近乎最佳的LPH:我们在通用组模型中为分布式离散对数的LPH和算法之间建立了一般的双向连接。使用Dinur等人的这种算法。 (Crypto 2018),我们获得的LPHS几乎是$δ= \ tilde o(1/d^2)$。这给出了一个与众不同的例子,说明基于群体的加密在量词后世界中有用。我们将阳性结果扩展到非循环和最差的LPH变体。 *多维LPH:我们获得了LPH的多维扩展的阳性和负结果,从而取得了最佳的二维LPH的进展。 *应用程序:我们通过介绍加密和算法应用来证明LPH的有用性。特别是,我们应用多维的LPH来获得有效的同构秘密共享的“包装”实现,并实现了对位置敏感的加密的倍率实现,其解密需要显着重叠的视图。
Can we sense our location in an unfamiliar environment by taking a sublinear-size sample of our surroundings? Can we efficiently encrypt a message that only someone physically close to us can decrypt? To solve this kind of problems, we introduce and study a new type of hash functions for finding shifts in sublinear time. A function $h:\{0,1\}^n\to \mathbb{Z}_n$ is a $(d,δ)$ {\em locality-preserving hash function for shifts} (LPHS) if: (1) $h$ can be computed by (adaptively) querying $d$ bits of its input, and (2) $\Pr [ h(x) \neq h(x \ll 1) + 1 ] \leq δ$, where $x$ is random and $\ll 1$ denotes a cyclic shift by one bit to the left. We make the following contributions. * Near-optimal LPHS via Distributed Discrete Log: We establish a general two-way connection between LPHS and algorithms for distributed discrete logarithm in the generic group model. Using such an algorithm of Dinur et al. (Crypto 2018), we get LPHS with near-optimal error of $δ=\tilde O(1/d^2)$. This gives an unusual example for the usefulness of group-based cryptography in a post-quantum world. We extend the positive result to non-cyclic and worst-case variants of LPHS. * Multidimensional LPHS: We obtain positive and negative results for a multidimensional extension of LPHS, making progress towards an optimal 2-dimensional LPHS. * Applications: We demonstrate the usefulness of LPHS by presenting cryptographic and algorithmic applications. In particular, we apply multidimensional LPHS to obtain an efficient "packed" implementation of homomorphic secret sharing and a sublinear-time implementation of location-sensitive encryption whose decryption requires a significantly overlapping view.