The implementation guidance for practicing network isolation by referring to ISO-17799 standard

In these years, the company budgets are raised dramatically for eliminating the security problems or mitigating the security risks in companies, but the numbers of incidents happening on computer systems in intranet or internet are still increasing. Many researchers proposed the way–to isolate the computers storing sensitive information for preventing information on these computers revealed or vulnerability on these computers exploited. However, there are few materials available for implementing network isolation. In this paper, we define ways of network isolation, “physical isolation” and “logical isolation”. In ISO-17799, there is no implementation guidance for practicing network logical isolation but auditing network physical isolation. This paper also provides the implementation guidance of network isolation in two aspects. One is for the technique viewpoints. The other aspect is for management viewpoints. These proposed implementation outlines and security measures will be considered in revising the security plan, “The Implementation Plan for Information Security Level in Government Departments” [“The implementation plan for information security level in government departments,” National Information and Communication Security Taskforce, Taiwan R.O.C., Programs, Jul. 20 2005].     

An efficient multi-exponentiation scheme based on modified Booth's method

We propose an efficient multi-exponentiation algorithm based on the modified Booth' algorithm and Montgomery's modular multiplication algorithm. The multi-exponentiation algorithm can be used to implement fast modern cryptosystems. Owing to the reduced number of multiplications, this algorithm is about 10% faster than Pekmestzi's algorithms. The proposed algorithm can be implemented in hardware as a small component. The component can then be used to form an efficient modular multi-exponentiation module by combining it with an efficient Montgomery modular multiplication module.     

A parallel residue-to-binary conversion algorithm without trial division

In recent years, the conversion of residue numbers to a binary integer has been intensively studied. The Chinese Remainder Theorem (CRT) is a solution to this conversion problem of a number to the Residue Number System with a general moduli set. This paper presents a new division-free conversion approach for the conversion of residue numbers to a binary integer. The algorithm differs from others employing a great number of division instructions by using shift instructions instead. These simple instructions keep the power consumption lower. This algorithm can also be implemented with a lookup table or upon a vector machine. Both make the conversion process efficient. This division-free algorithm employs the concept of Montgomery multiplication algorithm. There are two variations of Montgomery algorithm proposed, which are algorithms MMA and IMA. The algorithm MMA is to transform the input number into the output presentation of Montgomery algorithm. Algorithm IMA is therefore inverse the computation of Montgomery algorithm to obtain the multiplicand. These two algorithms are in the complexity of O(n), where n is log₂ q_i. q_i is a modulus. The proposed algorithm for converting the residues to a binary integer therefore runs on O(n × log m) times on O(m) processors. There are O(log m) iterations of O(n) complexity. Compared with the traditional conversion algorithm, the advantages of this proposed algorithm are not only in employing simpler operations but also in performing fewer iterations.     

Parallel computational algorithms for generalized Chinese remainder theorem

Recently, the residue number system (RNS) has been intensively studied. The Chinese remainder theorem (CRT) is a solution to the conversion problem of a number to RNS with a general moduli set. This paper introduces the generalized CRT (GCRT) with parallel algorithms used for the conversion. The GCRT differs from the CRT because it has the advantage of having more applications than does the CRT. The GCRT, however, has a disadvantage in computational performance. To remedy this shortcoming, this paper proposes algorithms that calculate concurrently for some non-related program fragments of GCRT computation. These proposed algorithms also allow the GCRT to compute more efficiently.