• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.25 no.2
• /
• pp.261-270
• /
• 2015

In information security devices, such as Smart Cards, vulnerabilities of the RSA algorithm which is used to protect the data were found in the Side Channel Analysis. The RSA is especially vulnerable to Power Analysis which uses power consumption when the algorithm is working. Typically Power Analysis is divided into SPA(Simple Power Analysis) and DPA(Differential Power Analysis). On top of this, there is a CA(Collision Analysis) which is a very powerful attack. CA makes it possible to attack using a single waveform, even if the algorithm is designed to secure against SPA and DPA. So Message blinding, which applies the window method, was considered as a countermeasure. But, this method does not provide sufficient safety when the window size is small. Therefore, in this paper, we propose a new countermeasure that provides higher safety against CA. Our countermeasure is a combination of message and exponent blinding which is applied to the window method. In addition, through experiments, we have shown that our countermeasure provides approximately 124% higher attack complexity when the window size is small. Thus it can provide higher safety against CA.

• Bulletin of the Korean Mathematical Society
• /
• v.46 no.4
• /
• pp.721-741
• /
• 2009

Consider RSA with N = pq, q < p < 2q, public encryption exponent e and private decryption exponent d. We first study cryptanalysis of RSA when certain amount of the Most Significant Bits (MSBs) or Least Significant Bits (LSBs) of d is known. The basic lattice based technique is similar to that of Ernst et al. in Eurocrypt 2005. However, our idea of guessing a few MSBs of the secret prime p substantially reduces the requirement of MSBs or LSBs of d for the key exposure attack. Further, we consider the RSA variant proposed by Sun and Yang in PKC 2005 and show that the partial key exposure attack works significantly on this variant.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2001.10b
• /
• pp.839-842
• /
• 2001

자바카드 API는 스마트 카드와 같은 작은 메모리를 가진 임베디드 장치에서 실행환경을 최적화하기 위해 구성되었다. 자바카드 API의 목적은 한정된 메모리를 가진 스마트카드 기반의 프로그램을 개발한 때 많은 이점을 제공한다. 본 논문에서는 자바 카드 API를 이용하여 공개키 암호 알고리즘 중에서 대표적인 RSA 알고리즘을 구현하는 것에 목적을 둔다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2002.11b
• /
• pp.1383-1386
• /
• 2002

Ad Hoc 네트워크는 베이스 스테이션이나 이동스위칭 센터와 같은 기존의 고정 된 infrastructure가 없는 이동 호스트들을 위한 새로운 패러다임이다. 본 논문에서는 기존의 Table-driven 방식과 On-demand 라우팅의 장점을 접목시킨 2-tier 계층구조를 사용한 다이나믹 라우팅 기법과 이를 바탕으로 효율적인 routing 경로를 확보하면서도 구조적으로 취약한 보안 위협 요소들에 대한 안정성을 제공하는 클러스터 노드간에 RSA기법을 사용한 인증 알고리즘을 제안한다.

• The Journal of the Korea Contents Association
• /
• v.6 no.11
• /
• pp.1-7
• /
• 2006

In this paper, a SOAP based ebXML cryptography system is proposed for the optimum XML document encryption using RSA algorithm in e-Marketplace. And ciphering algorithms of DES, 3DES, RSA, and proposed RSA were used for the performance analysis of ebXML cryptography system. The network performance of ciphering and deciphering times is evaluated for its enhancement of SOAP based ebXML ciphering e-Marketplace systems using the same block and document sizes by computer simulations.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.26 no.2
• /
• pp.335-344
• /
• 2016

It is known that power analysis is one of the most powerful attack in side channel analysis. Among power analysis single trace attack is widely studied recently since it uses one power consumption trace to recover secret key of public cryptosystem. Recently Sim et al. proposed new exponentiation algorithm for RSA cryptosystem with higher attack complexity to prevent single trace attack. In this paper we analyze the vulnerability of exponentiation algorithm described by Sim et al. Sim et al. applied message blinding and random exponentiation splitting method on $2^t-ary$ for higher attack complexity. However we can reveal private key using information exposed during pre-computation generation. Also we describe modified algorithm that provides higher attack complexity on collision attack. Proposed algorithm minimized the reuse of value that are used during exponentiation to provide security under single collision attack.

• Journal of Internet Computing and Services
• /
• v.5 no.6
• /
• pp.45-58
• /
• 2004

This paper consists of two parts, One is the ECC( GF(2/sup m/)) algorithm to improve the security strength and the processing time of SSL VPN and the other is the WLCAPT algorithm instead of LSNAT for the security strength of virtual server. In general when corporates use SSL protocol in order to build VPN, they use RSA algorithm with the problem of security and processing time about authentication and confidentiality, In this paper, a shared public key is generated with ECSPK which uses ECC( GF(2/sup m/)) algorithm to improve the security and processing time instead of RSA In addition, WLCAPT algorithm proposed in this paper is applied to virtual server which resides in the server side and then after NAT translation, the actual server of headquarter is securely communicated with it.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.9
• /
• pp.3841-3857
• /
• 2020

RSA is one of the best well-known public key cryptosystems. This methodology is widely used at present because there is not any algorithm which can break this system that has all strong parameters within polynomial time. However, it may be easily broken when at least one parameter is weak. In fact, many weak parameters are already found and are solved by some algorithms. Some examples of weak parameters consist of a small private key, a large private key, a small prime factor and a small result of the difference between two prime factors. In this paper, the new weakness of RSA is proposed. Assuming Euler's totient value, Φ (n), can be rewritten as Φ (n) = ad + b, where d is the private key and a, b ∈ ℤ, if a divides both of Φ (n) and b and the new exponent for the decryption equation is a small integer, this condition is assigned as the new weakness for breaking RSA. Firstly, the specific algorithm which is created for this weakness directly is proposed. Secondly, two equations are presented to find a, b and d. In fact, one of two equations must be implemented to find a and b at first. After that, the other equation is chosen to find d. The experimental results show that if this weakness has happened and the new exponent is small, original plaintext, m, will be recovered very fast. Furthermore, number of steps to recover d are very small when a is large. However, if a is too large, d may not be recovered because m which must be always written as m = h^a is higher than modulus.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.10 no.4
• /
• pp.81-93
• /
• 2000

In a methodological approach to improve the processing performance of modulo exponentiation which is the primary arithmetic in RSA crypto algorithm, we present a new RSA hardware architecture based on high-radix modulo multiplication and CRT(Chinese Remainder Theorem). By implementing the modulo multiplier using radix-16 arithmetic, we reduced the number of PE(Processing Element)s by quarter comparing to the binary arithmetic scheme. This leads to having the number of clock cycles and the delay of pipelining flip-flops be reduced by quarter respectively. Because the receiver knows p and q, factors of N, it is possible to apply the CRT to the decryption process. To use CRT, we made two s/2-bit multipliers operating in parallel at decryption, which accomplished 4 times faster performance than when not using the CRT. In encryption phase, the two s/2-bit multipliers can be connected to make a s-bit linear multiplier for the s-bit arithmetic operation. We limited the encryption exponent size up to 17-bit to maintain high speed, We implemented a linear array modulo multiplier by projecting horizontally the DG of Montgomery algorithm. The H/W proposed here performs encryption with 15Mbps bit-rate and decryption with 1.22Mbps, when estimated with reference to Samsung 0.5um CMOS Standard Cell Library, which is the fastest among the publications at present.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2012.05a
• /
• pp.53-53
• /
• 2012