• Journal of the Chungcheong Mathematical Society
• /
• v.22 no.4
• /
• pp.789-797
• /
• 2009

Invertible transformations over n-bit words are essential ingredients in many cryptographic constructions. When n is large (e.g., n = 64) such invertible transformations are usually represented as a composition of simpler operations such as linear functions, S-P networks, Feistel structures and T-functions. Among them we will study T-functions which are probably invertible transformation and are very useful in stream ciphers. In this paper we will show that $f(x)=x+(g(x)^2{\vee}C)$ mod $2^n$ is a permutation with a single cycle of length $2^n$ if both the least significant bit and the third significant bit in the constant C are 1, where g(x) is a T-function.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.10a
• /
• pp.334-336
• /
• 2004

국내 전자상거래 제품과의 호환성과 확장성을 위하여 국내 전자서명 표준인 KCDSA(Korean Certificate-based Digital Signature Algorithm) 메커니즘을 PKCS(Public Key Cryptographic Standard) #11 암호 API(Application Programming Interface)에 기능을 추가한다. PKCS #11에서 정의한 키 관리(Hey Management) 함수의 입력 파라미터에 암호화할 키를 바로 입력하면 변조된 키를 전달할 수 있으므로, 본 논문에서는 안전한 키보호(Key Protection) 함수를 새로 정의하여 암호화할 키 대신 사용자 PIN(Personal Identification Number: 패스워드) 입력하여 사용자의 KCDSA 개인키와 공개키를 보다 더 안전하게 보관하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.5
• /
• pp.1069-1075
• /
• 2007

New BESA cryptographic algorithm is suitable network environment and wire/wireless communication network, on implement easy, security rate preservation, scalable & reconfigurable. Though proposed algorithm strengthens security vulnerability of TCP/IP protocol and keep security about many user as that have authentication function in network environment, there is important purpose. So that new BESA cryptographic algorithm implemented by hardware base cryptosystem and en/decryption is achieved at the same time, composed architecture.

• ETRI Journal
• /
• v.45 no.2
• /
• pp.346-357
• /
• 2023

Hardware security primitives, also known as physical unclonable functions (PUFs), perform innovative roles to extract the randomness unique to specific hardware. This paper proposes a novel hardware security primitive using a commercial off-the-shelf flash memory chip that is an intrinsic part of most commercial Internet of Things (IoT) devices. First, we define a hardware security source model to describe a hardware-based fixed random bit generator for use in security applications, such as cryptographic key generation. Then, we propose a hardware security primitive with flash memory by exploiting the variability of tunneling electrons in the floating gate. In accordance with the requirements for robustness against the environment, timing variations, and random errors, we developed an adaptive extraction algorithm for the flash PUF. Experimental results show that the proposed flash PUF successfully generates a fixed random response, where the uniqueness is 49.1%, steadiness is 3.8%, uniformity is 50.2%, and min-entropy per bit is 0.87. Thus, our approach can be applied to security applications with reliability and satisfy high-entropy requirements, such as cryptographic key generation for IoT devices.

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

• The KIPS Transactions:PartC
• /
• v.19C no.1
• /
• pp.9-18
• /
• 2012

In 2010, Pedro et al. proposed RFID distance bounding protocol based on WSBC cryptographic puzzle. This paper points out that Pedro et al.'s protocol not only is vulnerable to tag privacy invasion attack and location tracking attack because an attacker can easily obtain the secret key(ID) of a legal tag from the intercepted messages between the reader and the tag, but also requires heavy computation by performing symmetric key operations of the resource limited passive tag and many communication rounds between the reader and the tag. Moreover, to resolve the security weakness and the computation/communication efficiency problems, this paper also present a new RFID distance bounding protocol based on WSBC cryptographic puzzle that can provide strong security and high efficiency. As a result, the proposed protocol not only provides computational and communicational efficiency because it requires secure one-way hash function for the passive tag and it reduces communication rounds, but also provides strong security because both tag and reader use secure one-way hash function to protect their exchanging messages.

• Proceedings of the IEEK Conference
• /
• 2004.06a
• /
• pp.297-300
• /
• 2004

In cellular communication, subscriber authentication is an essential technique. The mobile station should operate in conjunction with the base station to authenticate the identity. In CDMA system, authentication is the process by which information is exchanged between a mobile station and base station for the purpose of confirming the mobile station. A successful authentication process means that the mobile station and base station process identical sets of shared secret data(SSD). SSD can be generated by authentication algorithms. The cryptographic hash function is a practical way of authentication algorithms. In this paper, we propose and implement MD5 and SHA-1 with modified structure.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.7 no.5
• /
• pp.1027-1032
• /
• 2012

Importance of security is emphasized along with development of local area network such as NFC, Bluetooth, WiFi etc., but research that is worth watching eagerly up to now is not gone. This paper proposed SSEN algorithm for security elevation of approximation communication network. Proposed SSEN algorithm is algorithm that special cryptographic function creates own key without necessity. Also, SSEN achieving certification function additionally, did so that can have more than performance about the processing speed and mistake of service voluntarily.

• Journal of the Chungcheong Mathematical Society
• /
• v.21 no.2
• /
• pp.259-268
• /
• 2008

To the design of secret key, there are two types of basic approaches called the tame approach and the wild approach. In the tame approach we try to use only simple primitives such as linear feedback shift registers and to prove mathematical theorems about their cryptographic properties. In the wild approach we try to use crazy compositions of operations which mix a variety of domains in a nonlinear and nonalgebraic way. There are several papers which try to bridge this gap by considering semi-wild constructions. A T-function on n-bit words plays an important role in semi-wild constructions. In this paper we study the invertibility and the period of some T-functions. Especially we characterize some polynomials which has a single cycle property.

• Journal of IKEEE
• /
• v.22 no.1
• /
• pp.38-45
• /
• 2018

An integrated cryptographic processor that efficiently integrates ARIA, AES block ciphers and Whirlpool hash function into a single hardware architecture is described. Based on the algorithm characteristics of ARIA, AES, and Whirlpool, we optimized the design so that the hardware resources of the substitution layer and the diffusion layer were shared. The round block was designed to operate in a time-division manner for the round transformation and the round key expansion of the Whirlpool hash, resulting in a lightweight hardware implementation. The hardware operation of the integrated ARIA-AES-Whirlpool crypto-processor was verified by Virtex5 FPGA implementation, and it occupied 68,531 gate equivalents (GEs) with a 0.18um CMOS cell library. When operating at 80 MHz clock frequency, it was estimated that the throughputs of ARIA, AES block ciphers, and Whirlpool hash were 602~787 Mbps, 682~930 Mbps, and 512 Mbps, respectively.