13,120 research outputs found
Low-Complexity Cryptographic Hash Functions
Cryptographic hash functions are efficiently computable functions that shrink a long input into a shorter output while achieving some of the useful security properties of a random function.
The most common type of such hash functions is collision resistant hash functions (CRH), which prevent an efficient attacker from finding a pair of inputs on which the function has the same output
Overview of blockchain technology cryptographic security
This thesis work is aimed at developing understanding of the hash functions and algorithms being used in blockchain technologies Bitcoin in comparison to Ethereum and private blockchain hash functions. This study attempts to answer one fundamental research question: âWhat considerations are important in assessing blockchain cryptographic security, with an emphasis on hash functionsâ.
The study was carried out qualitatively using a desk research approach and combining this approach with using two public blockchains-based cryptocurrencies; Ethereum and Bitcoin as case studies. The research aims to provide a holistic view of blockchain cryptographic security comparing Bitcoin and Ethereum as use cases, and thus providing a consolidated document which students studying cryptography can access to obtain a better understanding of what is involved in blockchain security. From an academic perspective, the research aims at providing a model which can be used in assessing what is important to consider in the cryptographic security of blockchains.
Three main categories of factors considered were presented in the proposed model which were strategical factors, complexity attributes and technical drivers. This results in a base crucial metrics such as absence of secret seeds, efficiency of verification, preimage collision resistance, fixed output size, low collision probability, and even distribution of preimages in output
Transparent code authentication at the processor level
The authors present a lightweight authentication mechanism that verifies the authenticity of code and thereby addresses the virus and malicious code problems at the hardware level eliminating the need for trusted extensions in the operating system. The technique proposed tightly integrates the authentication mechanism into the processor core. The authentication latency is hidden behind the memory access latency, thereby allowing seamless on-the-fly authentication of instructions. In addition, the proposed authentication method supports seamless encryption of code (and static data). Consequently, while providing the software users with assurance for authenticity of programs executing on their hardware, the proposed technique also protects the software manufacturersâ intellectual property through encryption. The performance analysis shows that, under mild assumptions, the presented technique introduces negligible overhead for even moderate cache sizes
Year 2010 Issues on Cryptographic Algorithms
In the financial sector, cryptographic algorithms are used as fundamental techniques for assuring confidentiality and integrity of data used in financial transactions and for authenticating entities involved in the transactions. Currently, the most widely used algorithms appear to be two-key triple DES and RC4 for symmetric ciphers, RSA with a 1024-bit key for an asymmetric cipher and a digital signature, and SHA-1 for a hash function according to international standards and guidelines related to the financial transactions. However, according to academic papers and reports regarding the security evaluation for such algorithms, it is difficult to ensure enough security by using the algorithms for a long time period, such as 10 or 15 years, due to advances in cryptanalysis techniques, improvement of computing power, and so on. To enhance the transition to more secure ones, National Institute of Standards and Technology (NIST) of the United States describes in various guidelines that NIST will no longer approve two-key triple DES, RSA with a 1024-bit key, and SHA-1 as the algorithms suitable for IT systems of the U.S. Federal Government after 2010. It is an important issue how to advance the transition of the algorithms in the financial sector. This paper refers to issues regarding the transition as Year 2010 issues in cryptographic algorithms. To successfully complete the transition by 2010, the deadline set by NIST, it is necessary for financial institutions to begin discussing the issues at the earliest possible date. This paper summarizes security evaluation results of the current algorithms, and describes Year 2010 issues, their impact on the financial industry, and the transition plan announced by NIST. This paper also shows several points to be discussed when dealing with Year 2010 issues.Cryptographic algorithm; Symmetric cipher; Asymmetric cipher; Security; Year 2010 issues; Hash function
Hardware-based Security for Virtual Trusted Platform Modules
Virtual Trusted Platform modules (TPMs) were proposed as a software-based
alternative to the hardware-based TPMs to allow the use of their cryptographic
functionalities in scenarios where multiple TPMs are required in a single
platform, such as in virtualized environments. However, virtualizing TPMs,
especially virutalizing the Platform Configuration Registers (PCRs), strikes
against one of the core principles of Trusted Computing, namely the need for a
hardware-based root of trust. In this paper we show how strength of
hardware-based security can be gained in virtual PCRs by binding them to their
corresponding hardware PCRs. We propose two approaches for such a binding. For
this purpose, the first variant uses binary hash trees, whereas the other
variant uses incremental hashing. In addition, we present an FPGA-based
implementation of both variants and evaluate their performance
IMPROVING SMART GRID SECURITY USING MERKLE TREES
AbstractâPresently nations worldwide are starting to convert their aging electrical power infrastructures into modern, dynamic power grids. Smart Grid offers much in the way of efficiencies and robustness to the electrical power grid, however its heavy reliance on communication networks will leave it more vulnerable to attack than present day grids. This paper looks at the threat to public key cryptography systems from a fully realized quantum computer and how this could impact the Smart Grid. We argue for the use of Merkle Trees in place of public key cryptography for authentication of devices in wireless mesh networks that are used in Smart Grid applications
High-level Cryptographic Abstractions
The interfaces exposed by commonly used cryptographic libraries are clumsy,
complicated, and assume an understanding of cryptographic algorithms. The
challenge is to design high-level abstractions that require minimum knowledge
and effort to use while also allowing maximum control when needed.
This paper proposes such high-level abstractions consisting of simple
cryptographic primitives and full declarative configuration. These abstractions
can be implemented on top of any cryptographic library in any language. We have
implemented these abstractions in Python, and used them to write a wide variety
of well-known security protocols, including Signal, Kerberos, and TLS.
We show that programs using our abstractions are much smaller and easier to
write than using low-level libraries, where size of security protocols
implemented is reduced by about a third on average. We show our implementation
incurs a small overhead, less than 5 microseconds for shared key operations and
less than 341 microseconds (< 1%) for public key operations. We also show our
abstractions are safe against main types of cryptographic misuse reported in
the literature
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