• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.6
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• pp.185-190
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• 2009

As the use of RSA based on chinese remainder theorem(CRT-RSA) is being generalized, the security of CRT-RSA has been important. Since Bellcore researchers introduced the fault attacks on CRT-RSA, various countermeasures have been proposed. In 1999, Shamir firstly proposed a countermeasure using checking procedure. After Shamir's countermeasure was introduced, various countermeasures based on checking procedure have been proposed. However, Shamir's countermeasure was known to be vulnerable to the modified operand attack by Joey et al. in 2001, and the checking procedure was known to be vulnerable to the modified opcode attack by Yen et al. in 2003. Yen et al. proposed a new countermeasure without checking procedure, but their countermeasure was known to be also vulnerable to the modified operand attack by Yen and Kim in 2007. In this paper, we point out that pre, but countermeasures were vulnerable to the modified operand attack or the modified opcode attack.

• ETRI Journal
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• v.38 no.2
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• pp.326-336
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• 2016

We propose and describe new error control algorithms for redundant residue number systems (RRNSs) and residue number system product codes. These algorithms employ search techniques for obtaining error values from within a set of values (that contains all possible error values). For a given RRNS, the error control algorithms have a computational complexity of $t{\cdot}O(log_2\;n+log_2\;{\bar{m}})$ comparison operations, where t denotes the error correcting capability, n denotes the number of moduli, and ${\bar{m}}$ denotes the geometric average of moduli. These algorithms avoid most modular operations. We describe a refinement to the proposed algorithms that further avoids the modular operation required in their respective first steps, with an increase of ${\lceil}log_2\;n{\rceil}$ to their computational complexity. The new algorithms provide significant computational advantages over existing methods.

• The KIPS Transactions:PartC
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• v.19C no.1
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• pp.39-46
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• 2012

In this paper, we propose a key distribution scheme for flexible chipset pairing conditional access system. Chipset pairing conditional access system is the implementation of CA (Conditional Access) module by using both embedded secure chip in a Set-Top Box(STB) and smartcard, and the secure chip embedded in a STB forms a secure channel between the smartcard and the STB. In short, it is the system that a smartcard outputs encrypted CW (Control Word) to the STB, and the STB decrypts an encrypted CW by using the embedded secure chip. The drawback of this chipset pairing conditional access system is that one smartcard is able to be used for only one specified STB since it is the system using the STB bound to a smartcard. However, the key distribution scheme proposed in this paper overcomes a drawback of current chipset pairing conditional access system by using Chinese Remainder Theorem(CRT). To be specific, with this scheme, one smartcard can be used for multiple, not single, STBs, and applied to current chipset pairing without great changes.