Improved security analysis for OMAC as a pseudorandom function

2009 ◽  
Vol 3 (2) ◽  
Author(s):  
Mridul Nandi
Keyword(s):  
Security Analysis ◽  
Pseudorandom Function

scholarly journals Orthros: A Low-Latency PRF

2021 ◽  
pp. 37-77
Author(s):  
Subhadeep Banik ◽  
Takanori Isobe ◽  
Fukang Liu ◽  
Kazuhiko Minematsu ◽  
Kosei Sakamoto
Keyword(s):  
Hardware Implementation ◽  
Block Cipher ◽  
State Of The Art ◽  
Security Analysis ◽  
Parallel Structure ◽  
Low Latency ◽  
Round Function ◽  
Minimum Latency ◽  
Primary Focus ◽  
Pseudorandom Function

We present Orthros, a 128-bit block pseudorandom function. It is designed with primary focus on latency of fully unrolled circuits. For this purpose, we adopt a parallel structure comprising two keyed permutations. The round function of each permutation is similar to Midori, a low-energy block cipher, however we thoroughly revise it to reduce latency, and introduce different rounds to significantly improve cryptographic strength in a small number of rounds. We provide a comprehensive, dedicated security analysis. For hardware implementation, Orthros achieves the lowest latency among the state-of-the-art low-latency primitives. For example, using the STM 90nm library, Orthros achieves a minimum latency of around 2.4 ns, while other constructions like PRINCE, Midori-128 and QARMA9-128- σ0 achieve 2.56 ns, 4.10 ns, 4.38 ns respectively.

scholarly journals Revisiting Variable Output Length XOR Pseudorandom Function

2018 ◽  
pp. 314-335 ◽  
Author(s):  
Srimanta Bhattacharya ◽  
Mridul Nandi
Keyword(s):  
Linear Equations ◽  
Security Analysis ◽  
Basic Structure ◽  
Authenticated Encryption ◽  
Security Proof ◽  
Simple Variant ◽  
Encryption Algorithms ◽  
The Cost ◽  
Mirror Theory ◽  
Pseudorandom Function

Let σ be some positive integer and C ⊆ {(i, j) : 1 ≤ i < j ≤ σ}. The theory behind finding a lower bound on the number of distinct blocks P1, . . . , Pσ ∈ {0, 1}n satisfying a set of linear equations {Pi ⊕Pj = ci,j : (i, j) ∈ C} for some ci,j ∈ {0, 1}n, is called mirror theory. Patarin introduced the mirror theory and provided a proof for this. However, the proof, even for a special class of equations, is complex and contains several non-trivial gaps. As an application of mirror theory, XORP[w] (known as XOR construction) returning (w−1) block output, is a pseudorandom function (PRF) for some parameter w, called width. The XOR construction can be seen as a basic structure of some encryption algorithms, e.g., the CENC encryption and the CHM authenticated encryption, proposed by Iwata in 2006. Due to potential application of XORP[w] and the nontrivial gaps in the proof of mirror theory, an alternative simpler analysis of PRF-security of XORP[w] would be much desired. Recently (in Crypto 2017) Dai et al. introduced a tool, called the χ2 method, for analyzing PRF-security. Using this tool, the authors have provided a proof of PRF-security of XORP[2] without relying on the mirror theory. In this paper, we resolve the general case; we apply the χ2 method to obtain a simpler security proof of XORP[w] for any w ≥ 2. For w = 2, we obtain a tighter bound for a wider range of parameters than that of Dai et al.. Moreover, we consider variable width construction XORP[∗] (in which the widths are chosen by adversaries adaptively), and also provide variable output length pseudorandom function (VOLPRF) security analysis for it. As an application of VOLPRF, we propose an authenticated encryption which is a simple variant of CHM or AES-GCM and provides much higher security than those at the cost of one extra blockcipher call for every message.

scholarly journals Achieve Efficient and Privacy-Preserving Compound Substring Query over Cloud

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Fan Yin ◽  
Rongxing Lu ◽  
Yandong Zheng ◽  
Xiaohu Tang
Keyword(s):  
Data Privacy ◽  
Homomorphic Encryption ◽  
Security Analysis ◽  
Privacy Preserving ◽  
Computing Technique ◽  
Searchable Symmetric Encryption ◽  
Single Attribute ◽  
Multiple Attributes ◽  
Pseudorandom Function ◽  
Extensive Performance

The cloud computing technique, which was initially used to mitigate the explosive growth of data, has been required to take both data privacy and users’ query functionality into consideration. Searchable symmetric encryption (SSE) is a popular solution that can support efficient attribute queries over encrypted datasets in the cloud. In particular, some SSE schemes focus on the substring query, which deals with the situation that the user only remembers the substring of the queried attribute. However, all of them just consider substring queries on a single attribute, which cannot be used to achieve compound substring queries on multiple attributes. This paper aims to address this issue by proposing an efficient and privacy-preserving SSE scheme supporting compound substring queries. In specific, we first employ the position heap technique to design a novel tree-based index to support substring queries on a single attribute and employ pseudorandom function (PRF) and fully homomorphic encryption (FHE) techniques to protect its privacy. Then, based on the homomorphism of FHE, we design a filter algorithm to calculate the intersection of search results for different attributes, which can be used to support compound substring queries on multiple attributes. Detailed security analysis shows that our proposed scheme is privacy-preserving. In addition, extensive performance evaluations are also conducted, and the results demonstrate the efficiency of our proposed scheme.

scholarly journals Cryptanalysis of AES-PRF and Its Dual

2018 ◽  
pp. 161-191
Author(s):  
Patrick Derbez ◽  
Tetsu Iwata ◽  
Ling Sun ◽  
Siwei Sun ◽  
Yosuke Todo ◽  
...  
Keyword(s):  
Security Analysis ◽  
Security Evaluation ◽  
Input State ◽  
Differential Attack ◽  
Feed Forward ◽  
Output State ◽  
Distinguishing Attack ◽  
Zero Correlation ◽  
Linear Attack ◽  
Pseudorandom Function

A dedicated pseudorandom function (PRF) called AES-PRF was proposed by Mennink and Neves at FSE 2018 (ToSC 2017, Issue 3). AES-PRF is obtained from AES by using the output of the 5-th round as the feed-forward to the output state. This paper presents extensive security analysis of AES-PRF and its variants. Specifically, we consider unbalanced variants where the output of the s-th round is used as the feed-forward. We also analyze the security of “dual” constructions of the unbalanced variants, where the input state is used as the feed-forward to the output of the s-th round. We apply an impossible differential attack, zero-correlation linear attack, traditional differential attack, zero correlation linear distinguishing attack and a meet-in-the-middle attack on these PRFs and reduced round versions. We show that AES-PRF is broken whenever s ≤ 2 or s ≥ 6, or reduced to 7 rounds, and Dual-AES-PRF is broken whenever s ≤ 4 or s ≥ 8. Our results on AES-PRF improve the initial security evaluation by the designers in various ways, and our results on Dual-AES-PRF give the first insight to its security.

scholarly journals Tight Security Analysis of EHtM MAC

2017 ◽  
pp. 130-150 ◽  
Author(s):  
Avijit Dutta ◽  
Ashwin Jha ◽  
Mridul Nandi
Keyword(s):  
Security Analysis ◽  
Domain Size ◽  
Message Authentication ◽  
Authentication Code ◽  
Natural Approach ◽  
Input Size ◽  
Beyond Birthday Bound ◽  
Tight Security ◽  
Pseudorandom Function ◽  
Exact Security

The security of a probabilistic Message Authentication Code (MAC) usually depends on the uniqueness of the random salt which restricts the security to birthday bound of the salt size due to the collision on random salts (e.g XMACR). To overcome the birthday bound limit, the natural approach to use (a) either a larger random salt (e.g MACRX3 uses 3n bits of random salt where n is the input and output size of the underlying non-compressing pseudorandom function or PRF) or (b) a PRF with increased domain size (e.g RWMAC or Randomized WMAC). Enhanced Hashthen- Mask (EHtM), proposed by Minematsu in FSE 2010, is the first probabilistic MAC scheme that provides beyond birthday bound security without increasing the randomness of the salt and the domain size of the non-compressing PRF. The author proved the security of EHtM as long as the number of MAC query is smaller than 22n/3 where n is the input size of the underlying non-compressing PRF. In this paper, we provide the exact security bound of EHtM and prove that this construction offers security up to 23n/4 MAC queries. The exactness is shown by demonstrating a matching attack.

FOOD SECURITY ANALYSIS OF STAVROPOL KRAI

2020 ◽  
pp. 85-90
Author(s):  
Yu.M. Sklyarova ◽  
I.Yu. Sklyarov ◽  
E.N. Lapina
Keyword(s):  
Food Security ◽  
Security Analysis ◽  
Stavropol Krai

CONSTITUTIONAL AND LEGAL EXPERIENCE OF INTERACTION OF BICAMERAL PARLIAMENTS OF THE CIS COUNTRIES IN THE SPHERE OF FOOD SECURITY

2020 ◽  
Vol 10 (5) ◽  
pp. 43-49
Author(s):  
MARINA MARKHGEYM ◽  
◽  
ANNA BEZUGLAYA
Keyword(s):  
Food Security ◽  
Security Analysis ◽  
Legal Doctrine ◽  
Commonwealth Of Independent States ◽  
Independent States ◽  
Cis Countries

The article presents the author’s analysis of constitutional texts, regulations and analytical materials of the countries of the Commonwealth of Independent States in order to consolidate in them the consolidated powers of the chambers of parliaments associated with the implementation of food security. Analysis of legal acts of the studied group of states showed that the sphere of food security (as part of the agrarian and food sphere/function) is one of the eventual spheres of interaction between the chambers of parliament. In the course of the study, two approaches of states to the formalization of provisions related to food security in constitutional texts were identified. The first approach is to consolidate norms that indirectly affect the field of food security (Belarus, Kazakhstan, Russia); the second - in the absence of such provisions (Tajikistan and Uzbekistan). It has been established that the interaction of the chambers of parliaments in the field of food security is implemented through the adoption of laws, as well as through various parliamentary events (parliamentary hearings, round tables, seminars, meetings, etc.). It is concluded that the available options for interaction between the chambers of parliaments of states in the field of food security reflect their independent approaches, which are developed on the basis of legal doctrine and practice.

Sign in / Sign up

Export Citation Format

Share Document