Static-Memory-Hard Functions, and Modeling the Cost of Space vs. Time
Static-Memory-Hard Functions, and Modeling the Cost of Space vs. Time
复制标题
静态内存硬函数，以及对空间与时间成本进行建模
DOI：
10.1007/978-3-030-03807-6_2
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Sunoo Park
中科院分区：
文献类型：
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作者：
T. Dryja;Quanquan C. Liu;Sunoo Park
从（Alwen and Serbinenko，Stoc，2015年）开始进行的一系列研究，加深了我们对密码学中记忆硬度的概念的理解，这是确定大规模密码裂缝攻击的哈希功能的有用属性，并显示了记忆 - 已显示出 - 与图形鹅卵石的定义具有复杂的联系，在记忆力范围内尚未统一保证迄今为止被证明是关于本文的一系列建议的。新的贡献是我们的贡献，如下所示。在运行时），不要考虑静态内存使用（例如，磁盘上的内存）。有可能允许更大的内存需求，我们提出了一个静态内存功能（SHF）的新定义，该定义考虑到静态内存：我们Oracle访问大型预处理字符串的内存使用情况，可以将其视为哈希功能描述的一部分。哈希功能将受益于动态 - 内存 - 固定型和静态内存。新的Pebble游戏（“黑麦克布尔游戏”）和在我们提出的测量下具有最佳复杂性的新图形结构。 ），为有限的参数设置提供了可行性的初始证明。在PAR上：他们仅考虑时间和空间成本之间的线性比率实际上，非线性权衡会导致对手从线性折衷方案中雇用不同的策略。
A series of recent research starting with (Alwen and Serbinenko, STOC 2015) has deepened our understanding of the notion of memory-hardness in cryptography—a useful property of hash functions for deterring large-scale password-cracking attacks—and has shown memory-hardness to have intricate connections with the theory of graph pebbling. Definitions of memory-hardness are not yet unified in the somewhat nascent field of memory-hardness, however, and the guarantees proven to date are with respect to a range of proposed definitions. In this paper, we observe two significant and practical considerations that are not analyzed by existing models of memory-hardness, and propose new models to capture them, accompanied by constructions based on new hard-to-pebble graphs. Our contribution is two-fold, as follows. First, existing measures of memory-hardness only account for dynamic memory usage (i.e., memory read/written at runtime), and do not consider static memory usage (e.g., memory on disk). Among other things, this means that memory requirements considered by prior models are inherently upper-bounded by a hash function’s runtime; in contrast, counting static memory would potentially allow quantification of much larger memory requirements, decoupled from runtime. We propose a new definition of static-memory-hard function (SHF) which takes static memory into account: we model static memory usage by oracle access to a large preprocessed string, which may be considered part of the hash function description. Static memory requirements are complementary to dynamic memory requirements: neither can replace the other, and to deter large-scale password-cracking attacks, a hash function will benefit from being both dynamic-memory-hard and static-memory-hard. We give two SHF constructions based on pebbling. To prove static-memory-hardness, we define a new pebble game (“black-magic pebble game”), and new graph constructions with optimal complexity under our proposed measure. Moreover, we provide a prototype implementation of our first SHF construction (which is based on pebbling of a simple “cylinder” graph), providing an initial demonstration of practical feasibility for a limited range of parameter settings. Secondly, existing memory-hardness models implicitly assume that the cost of space and time are more or less on par: they consider only linear ratios between the costs of time and space. We propose a new model to capture nonlinear time-space trade-offs: e.g., how is the adversary impacted when space is quadratically more expensive than time? We prove that nonlinear tradeoffs can in fact cause adversaries to employ different strategies from linear tradeoffs.
DOI：
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发表时间：
2018
期刊：
Financial Cryptography and Data Security (FC 2018
影响因子：
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作者：
Jeremiah Blocki, Samson Zhou
通讯作者：
Jeremiah Blocki, Samson Zhou
关于 Argon2i 的深度鲁棒性和累积卵石成本
DOI：
10.1007/978-3-319-70500-2_15
发表时间：
2017
期刊：
Theory of Cryptography. TCC 2017
影响因子：
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作者：
Blocki, J.;Zhou, S.
通讯作者：
Zhou, S.
持续的空间复杂性
DOI：
10.1007/978-3-319-78375-8_4
发表时间：
2018
期刊：
Advances in Cryptology – EUROCRYPT 2018
影响因子：
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作者：
Alwen, Joël;Blocki, Jeremiah;Pietrzak, Krzysztof
通讯作者：
Pietrzak, Krzysztof