• Journal of Information Processing Systems
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• v.12 no.2
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• pp.310-321
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• 2016

TCS_SHA-3 is a family of four cryptographic hash functions that are covered by a United States patent (US 2009/0262925). The digest sizes are 224, 256, 384 and 512 bits. The hash functions use bijective functions in place of the standard compression functions. In this paper we describe first and second preimage attacks on the full hash functions. The second preimage attack requires negligible time and the first preimage attack requires $O(2^{36})$ time. In addition to these attacks, we also present a negligible time second preimage attack on a strengthened variant of the TCS_SHA-3. All the attacks have negligible memory requirements. To the best of our knowledge, there is no prior cryptanalysis of any member of the TCS_SHA-3 family in the literature.

• Journal of Information Processing Systems
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• v.6 no.4
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• pp.453-480
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• 2010

Cryptographic hash functions reduce inputs of arbitrary or very large length to a short string of fixed length. All hash function designs start from a compression function with fixed length inputs. The compression function itself is designed from scratch, or derived from a block cipher or a permutation. The most common procedure to extend the domain of a compression function in order to obtain a hash function is a simple linear iteration; however, some variants use multiple iterations or a tree structure that allows for parallelism. This paper presents a survey of 17 extenders in the literature. It considers the natural question whether these preserve the security properties of the compression function, and more in particular collision resistance, second preimage resistance, preimage resistance and the pseudo-random oracle property.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2388-2404
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• 2012

Cryptographic hash functions are widely used in many information security applications like digital signatures, message authentication codes (MACs), and other forms of authentication. In response to recent advances in cryptanalysis of commonly used hash algorithms, National Institute of Standards and Technology (NIST) announced a publicly open competition for selection of new standard Secure Hash Algorithm called SHA-3. One important aspect of this competition is evaluation of hardware performances of the candidates. In this work we present efficient hardware implementations of SHA-3 finalists: JH, Keccak and Skein. We propose high speed architectures using Look-Up Table (LUT) resources on FPGAs, to minimize chip area and to reduce critical path lengths. This approach allows us to design data paths of SHA-3 finalists with minimum resources and higher clock frequencies. We implemented and investigated the performance of these candidates on modern and latest FPGA devices from Xilinx. This work serves as performance investigation of leading SHA-3 finalists on most up-to-date FPGAs.

• Journal of Korea Multimedia Society
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• v.3 no.2
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• pp.133-139
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• 2000

In this paper we propose a secure and an efficient metering scheme for measuring the usage and the popularity of web pages. The proposed scheme is based on the cryptographic secure hash functions. Since the metering schemes based on cryptographic technology provides security, efficiency, accuracy and anonymity comparing to the existing metering schemes in WWW, they have the advantages that are secure against attempts by servers who inflate the number of clients and against attempt of collaboration of severs and clients.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.115-125
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• 2011

Cryptographic hash functions are also called one-way functions and they ensure the integrity of communication data and command by detecting or blocking forgery. Also hash functions can be used with other security protocols for signature, authentication, and key distribution. The SHA-1 was widely used until it was found to be cryptographically broken by Wang, et. al, 2005. For this reason, NIST launched the SHA-3 competition in November 2007 to develop new secure hash function by 2012. Many SHA-3 hash functions were proposed and currently in review process. To choose new SHA-3 hash function among the proposed hash functions, there have been many efforts to analyze the cryptographic secureness, hardware/software characteristics on each proposed one. However there are few research efforts on the SHA-3 from the point of power consumption, which is a crucial metric on hardware module. In this paper, we analyze the power consumption characteristics of the SHA-3 hash functions when they are made in the form of ASIC hardware module. Also we propose power efficient hardware architecture on Luffa, which is strong candidate as a new SHA-3 hash function. Our proposed low power architecture for Luffa achieves 10% less power consumption than previous Luffa hardware architecture.

• Asia pacific journal of information systems
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• v.30 no.1
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• pp.21-30
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• 2020

Bitcoin (BTC) is a type of cryptocurrency that supports transaction/payment of virtual money between BTC users without the presence of a central authority or any third party like bank. It uses some cryptographic techniques namely public- and private-keys, digital signature and cryptographic-hash functions, and they are used for making secure transactions and maintaining distributed public ledger called blockchain. In BTC system, each transaction signed by sender is broadcasted over the P2P (Peer-to-Peer) Bitcoin network and a set of such transactions collected over a period is hashed together with the previous block/other values to form a block known as candidate block, where the first block known as genesis-block was created independently. Before a candidate block to be the part of existing blockchain (chaining of blocks), a computation-intensive hard problem needs to be solved. A number of miners try to solve it and a winner earns some BTCs as inspiration. The miners have high computing and hardware resources, and they play key roles in BTC for blockchain formation. This paper mainly analyses the underlying cryptographic techniques, identifies some weaknesses and proposes their enhancements. For these, two modifications of BTC are suggested ― (i) All BTC users must use digital certificates for their authentication and (ii) Winning miner must give signature on the compressed data of a block for authentication of public blocks/blockchain.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.3
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• pp.323-330
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• 2021

Recently, the advantages of high-speed arithmetic in quantum computers have been known, and interest in quantum circuits utilizing qubits has increased. The Grover algorithm is a quantum algorithm that can reduce n-bit security level symmetric key cryptography and hash functions to n/2-bit security level. Since the Grover algorithm work on quantum computers, the symmetric cryptographic technique and hash function to be applied must be implemented in a quantum circuit. This is the motivation for these studies, and recently, research on implementing symmetric cryptographic technique and hash functions in quantum circuits has been actively conducted. However, at present, in a situation where the number of qubits is limited, we are interested in implementing with the minimum number of qubits and aim for efficient implementation. In this paper, the domestic hash function LSH is efficiently implemented using qubits recycling and pre-computation. Also, major operations such as Mix and Final were efficiently implemented as quantum circuits using ProjectQ, a quantum programming tool provided by IBM, and the quantum resources required for this were evaluated.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.6
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• pp.1251-1259
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• 2017

One-time password has been proposed for the purpose of addressing the security problems of the simple password system: fixed passwords and pre-shared passwords. Since it employs the consecutive hash values after a root hash value is registered at the server, the security weakness of the fixed passwords has been addressed. However, it has a shortcoming of re-registering a new root hash value when the previous hash chain's hash values are exhausted. Even though several one-time password systems not requiring re-registration have been proposed, they all have several problems in terms of constraint conditions and efficiency. In this paper, we propose the one - time password scheme based on a hash chain that generates one - time passwords using only two cryptographic hash functions at each authentication and satisfies the existing constraints without re-registration, Security requirements and efficiency.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.951-954
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• 2002

This paper presents the implementation of hash functions for IPSEC chip. There is an increasing interest in high-speed cryptographic accelerators for IPSec applications such as VPNs (virtual private networks). Because diverse algorithms are used in Internet, various hash algorithms are required for IPSec chip. Therefore, we implemented SHA-1, HAS-160 and MD5 in one chip. These hash algorithms are designed to reduce the number of gates. SHA-1 module is combined with HAS-160 module. As the result, the required logic elements are reduced by 27%. These hash algorithms have been implemented using Altera's EP20K1000EBC652-3 with PCI bus interface.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.4
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• pp.295-302
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• 2013

In the network coding, throughput can be increased by allowing the transformation of the received data at the intermediate nodes. However, the adversary can obtain more information at the intermediate nodes and make troubles for decoding of transmitted data at the sink nodes by modifying transmitted data at the compromised nodes. In order to resist the adversary activities, various information theoretic or cryptographic secure network coding schemes are proposed. Recently, a secure network coding based on the cryptographic hash function can be used at the random network coding. However, because of the computational resource requirement for cryptographic hash functions, networks with limited computational resources such as sensor nodes have difficulties to use the cryptographic solution. In this paper, we propose a new secure network coding scheme which uses linear transformations and table lookup and safely transmits n-1 packets at the random network coding under the assumption that the adversary can eavesdrop at most n-1 nodes. It is shown that the proposed scheme is an all-or-nothing transform (AONT) and weakly secure network coding in the information theory.