Survey and Benchmark of Block Ciphers for Wireless Sensor Networks

Cryptographic algorithms play an important role in the security architecture of wireless sensor networks (WSNs). Choosing the most storage- and energy-efficient block cipher is essential, due to the facts that these networks are meant to operate without human intervention for a long period of time with little energy supply, and that available storage is scarce on these sensor nodes. However, to our knowledge, no systematic work has been done in this area so far.We construct an evaluation framework in which we first identify the candidates of block ciphers suitable for WSNs, based on existing literature and authoritative recommendations. For evaluating and assessing these candidates, we not only consider the security properties but also the storage- and energy-efficiency of the candidates. Finally, based on the evaluation results, we select the most suitable ciphers for WSNs, namely Skipjack, MISTY1, and Rijndael, depending on the combination of available memory and required security (energy efficiency being implicit). In terms of operation mode, we recommend Output Feedback Mode for pairwise links but Cipher Block Chaining for group communications

Теоретико-концептуальный подход к проблеме качества и ценности информации в эргасистеме

The theoretical and conceptual approach to information quality and value problem is considered. The approach includes the choice and determination of types and qualitative forms of information manifestation that are characteristic of the ergatic systems, the efficient distribution in ergatic system of the accepted information measures, the main requirements on measures of quantity and quality of structural and content information, the principal of information value.Рассматривается теоретико-концептуальный подход к проблеме качества и ценности информации в эргасистеме, включающий выбор и определение видов и качественных форм проявления информации, характерных для эргасистем, рациональное распределение в эргасистеме апробированных информационных мер, основные требования к мерам количества и качества структурной и содержательной информации, принцип информационной ценности

Partition-Based Trapdoor Ciphers

Trapdoors are a two-face key concept in modern cryptography. They are primarily related to the concept of trapdoor function used in asymmetric cryptography. A trapdoor function is a one-to-one mapping that is easy to compute, but for which its inverse function is difficult to compute without special information, called the trapdoor. It is a necessary condition to get reversibility between the sender and the receiver for encryption or between the signer and the verifier for digital signature. The trapdoor mechanism is always fully public and detailed. The second concept of trapdoor relates to the more subtle and perverse concept of mathematical backdoor, which is a key issue in symmetric cryptography. In this case, the aim is to insert hidden mathematical weaknesses, which enable one who knows them to break the cipher. Therefore, the existence of a backdoor is a strongly undesirable property. This book deals with this second concept and is focused on block ciphers or, more specifically, on substitution-permutation networks (SPN). Inserting a backdoor in an encryption algorithm gives an effective cryptanalysis of the cipher to the designer

Locating Encrypted Data Hidden Among Non-Encrypted Data using Statistical Tools

This research tests the security of software protection techniques that use encryption to protect code segments containing critical algorithm implementation to prevent reverse engineering. Using the National Institute of Standards and Technology (NIST) Tests for Randomness encrypted regions hidden among non-encrypted bits of a binary executable file are located. The location of ciphertext from four encryption algorithms (AES, DES, RSA, and TEA) and three block sizes (10, 100, and 500 32-bit words) were tested during the development of the techniques described in this research. The test files were generated from the Win32 binary executable file of Adobe\u27s Acrobat Reader version 7.0.9. The culmination of this effort developed a technique capable of locating 100% of the encryption regions with no false negative error and minimal false positive error with a 95% confidence. The encrypted region must be encrypted with a strong encryption algorithm whose ciphertext appears statistically random to the NIST Tests for Randomness, and the size of the encrypted region must be at least 100 32-bit words (3,200 bits)

Cryptanalysis of Dedicated Cryptographic Hash Functions

In this thesis we study the security of a number of dedicated cryptographic hash functions against cryptanalytic attacks. We begin with an introduction to what cryptographic hash functions are and what they are used for. This is followed by strict definitions of the security properties often required from cryptographic hash functions. FSB hashes are a class of hash functions derived from a coding theory problem. We attack FSB by modeling the compression function of the hash by a matrix in GF(2). We show that collisions and preimages can easily be found in FSB with the proposed security parameters. We describe a meet-in-the-middle attack against the FORK-256 hash function. The attack requires 2^112.8 operations to find a collision, which is a 38000-fold improvement over the expected 2^128 operations. We then present a method for finding slid pairs for the compression function of SHA-1; pairs of inputs and messages that produce closely related outputs in the compression function. We also cryptanalyse two block ciphers based on the compression function of MD5, MDC-MD5 and the Kaliski-Robshaw "Crab" encryption algorithm. VSH is a hash function based on problems in number theory that are believed to be hard. The original proposal only claims collision resistance; we demonstrate that VSH does not meet the other hash function requirements of preimage resistance, one-wayness, and collision resistance of truncated variants. To explore more general cryptanalytic attacks, we discuss the d-Monomial test, a statistical test that has been found to be effective in distinguishing iterated Boolean circuits from real random functions. The test is applied to the SHA and MD5 hash functions. We present a new hash function proposal, LASH, and its initial cryptanalysis.The LASH design is based on a simple underlying primitive, and some of its security can be shown to be related to lattice problems

Cryptanalysis of Dedicated Cryptographic Hash Functions

In this thesis we study the security of a number of dedicated cryptographic hash functions against cryptanalytic attacks. We begin with an introduction to what cryptographic hash functions are and what they are used for. This is followed by strict definitions of the security properties often required from cryptographic hash functions. FSB hashes are a class of hash functions derived from a coding theory problem. We attack FSB by modeling the compression function of the hash by a matrix in GF(2). We show that collisions and preimages can easily be found in FSB with the proposed security parameters. We describe a meet-in-the-middle attack against the FORK-256 hash function. The attack requires 2^112.8 operations to find a collision, which is a 38000-fold improvement over the expected 2^128 operations. We then present a method for finding slid pairs for the compression function of SHA-1; pairs of inputs and messages that produce closely related outputs in the compression function. We also cryptanalyse two block ciphers based on the compression function of MD5, MDC-MD5 and the Kaliski-Robshaw "Crab" encryption algorithm. VSH is a hash function based on problems in number theory that are believed to be hard. The original proposal only claims collision resistance; we demonstrate that VSH does not meet the other hash function requirements of preimage resistance, one-wayness, and collision resistance of truncated variants. To explore more general cryptanalytic attacks, we discuss the d-Monomial test, a statistical test that has been found to be effective in distinguishing iterated Boolean circuits from real random functions. The test is applied to the SHA and MD5 hash functions. We present a new hash function proposal, LASH, and its initial cryptanalysis.The LASH design is based on a simple underlying primitive, and some of its security can be shown to be related to lattice problems