• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1C
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• pp.117-123
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• 2008

We propose an improved Diffie-Hellman(DH) key agreement protocol over a radio link in peer-to-peer networks. The proposed protocol ensures a secure establishment of the shared key between two parties through distance bounding(DB). Proposed protocol is much improved in the sense that we now reduce the number of messages exchanged by two, the number of parameters maintained by four, and 2(7682(k/64)-64) of XOR operations, where k is the length of the random sequence used in the protocol. Also, it ensures a secure reusability of DH public parameters. Start after striking space key 2 times.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1201-1208
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• 2010

In this paper, we propose an image encryption method using two linear MLCA(Maximum Length Cellular Automata). The encryption method first sets arbitrary 8 bit initial values. Next, we create high quality PN(pseudo noise) sequences by converting rows and columns with the set initial values. hen we generate a basis image using the set PN sequences. Lastly, the final image with high encryption level is produced by XOR operation of the basis image and the original image. In order to verify that the proposed method has the high encryption level, we performed histogram and stability analysis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.164-167
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• 2009

In this paper, we propose the image encryption using LFSR(Linear Feedback Shift Register) and 2D CAT(Two-Dimensional Cellular Automata Transform). First, a LFSR is used to create a PN(pseudo noise) sequence, which is identical to the size of the original image. Then, the created sequence goes through a XOR operation with the original image to convert the original image. Next, the gateway value is set to produce a 2D CAT basis function. Using the created basis function, multiplication is done with the converted original image to process 2D CAT image encipherment. Lastly, the stability analysis verifies that the proposed method holds a high encryption quality status.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.953-955
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• 2009

In this paper, we propose an image encryption method using two linear MLCA(Maximum Length Cellular Automata). The encryption method first sets arbitrary 8 bit initial values. Next, we create high quality PN(pseudo noise) sequences by converting rows and columns with the set initial values. Then we generate a basis image using the set PN sequences. Lastly, the final image with high encryption level is produced by XOR operating the basis image and the original image. In order to verify that the proposed method has the high encryption level, we performed histogram and stability analysis.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.3
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• pp.63-73
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• 2004

This paper proposes an efficient authentication scheme for multicast packet using recovery layer to provide source authentication. The problems of the existing schemes are as follows ： TESLA requires time synchronization between the sender and the receiver, md hash-based schemes have high communication overheads due to additional hash values and require many buffers and delay for verification on receivers. Our main focus is reducing the buffer size, communication and computation burden of the receiver. The proposed scheme in this paper is highly robust to packet loss using the recovery layer based on XOR operation. It also provides low communication overhead, low verification cost, non-repudiation of the origin, immediate verification and robustness against DoS attack on the receiver.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.4
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• pp.841-849
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• 2012

Cloud computing that provides IT service and computer resource based on internet is now getting attention. However, the encrypted data can be exposed because it is saved in cloud server, even though it is saved as an encrypted data. In this paper, user certification protocol is proposed to prevent from illegally using of secret data by others while user who locates different physical position is providing secret data safely. The proposed protocol uses one way hash function and XOR calculation to get user's certification information which is in server when any user approaches to particular server remotely. Also it solves user security problem of cloud.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.3
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• pp.477-486
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• 2022

This study aims to present a method using event sourcing patterns and blockchain as a way to cope with vulnerabilities in memory manipulation at the client level. To verify the plan, the method of running the memory operation application was analyzed, and the performance was compared and analyzed when the memory operation prevention plan was applied by fabricating a test application. As a result of the analysis, the usage of memory increased compared to the method of XOR operation by storing major data in one memory, but it was possible to prevent the operation of the memory operation program without significantly affecting the performance of the game.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.11
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• pp.8-15
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• 2009

Side-channel attacks including the differential power analysis attack are often more powerful than classical cryptanalysis and have to be seriously considered by cryptographic algorithm's implementers. Various countermeasures have been proposed against such attacks. In this paper, we deal with the masking method, which is known to be a very effective countermeasure against the differential power analysis attack and propose new gate-level conversion methods between Boolean and arithmetic masks. The new methods require only 6n-5 XOR and 2n-2 AND gates with 3n-2 gate delay for converting n-bit masks. The basic idea of the proposed methods is that the carry and the sum bits in the ripple adder are manipulated in a way that the adversary cannot detect the relation between these bits and the original raw data. Since the proposed methods use only bitwise operations, they are especially useful for DPA-securely implementing cryptographic algorithms in hardware which use both Boolean and arithmetic operations. For example, we applied them to securely implement the block encryption algorithm SEED in hardware and present its detailed implementation result.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.12
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• pp.29-40
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• 2008

The efficient hardware design of finite field multiplication is an very important research topic for and efficient $f(x)=x^n+x^k+1$ implementation of cryptosystem based on arithmetic in finite field GF($2^n$). We used special generating trinomial to construct a bit-parallel multiplier over finite field with low space complexity. To reduce processing time, The hardware architecture of proposed multiplier is similar with existing Mastrovito multiplier. The complexity of proposed multiplier is depend on the degree of intermediate term $x^k$ and the space complexity of the new multiplier is $2k^2-2k+1$ lower than existing multiplier's. The time complexity of the proposed multiplier is equal to that of existing multiplier or increased to $1T_X(10%{\sim}12.5%$) but space complexity is reduced to maximum 25%.

• The KIPS Transactions:PartD
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• v.13D no.4 s.107
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• pp.455-462
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• 2006

Recently, the filtering approach using vector approximation such as VA-file[1] or LPC-file[2] have been proposed to support similarity search in high dimensional data space. This approach filters out many irrelevant vectors by calculating the approximate distance from a query vector using the compact approximations of vectors in database. Accordingly, the total elapsed time for similarity search is reduced because the disk I/O time is eliminated by reading the compact approximations instead of original vectors. However, the search time of the VA-file or LPC-file is not much lessened compared to the brute-force search because it requires a lot of computations for calculating the approximate distance. This paper proposes a new bitmap index structure in order to minimize the calculating time. To improve the calculating speed, a specific value of an object is saved in a bit pattern that shows a spatial position of the feature vector on a data space, and the calculation for a distance between objects is performed by the XOR bit calculation that is much faster than the real vector calculation. According to the experiment, the method that this paper suggests has shortened the total searching time to the extent of about one fourth of the sequential searching time, and to the utmost two times of the existing methods by shortening the great deal of calculating time, although this method has a longer data reading time compared to the existing vector approximation based approach. Consequently, it can be confirmed that we can improve even more the searching performance by shortening the calculating time for filtering of the existing vector approximation methods when the database speed is fast enough.