• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.05a
• /
• pp.233-236
• /
• 2008

Wire wireless integrated service of BcN(Broadband convergence Network) is expanding. Information Security issue is highlighted for opposing attack of getting information illegally on wire wireless network. The user of PKI(Public Key Infrastructure) cipher system among Information security technology receives various security services about authentication, confidentiality, integrity, non-repudiation and access control etc. A mobile client and server are loaded certificate and wireless internet cryptography module for trusted data send receive. And data sends receives to each other after certification process through validity check of certificate. Certificate and data security system is researched through PKI on wireless network environment and data security system in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.19 no.11
• /
• pp.2291-2302
• /
• 1994

This paper shows the implementation and design of special processor for linearly shift knapsack public key cryptography system. We highten the density of existing knapsack vector and shift the vectors linearly in order to implement the structure of linearly shift knapsack system which has the stronger cryptosystem. As it needs the parallel processing at each path according to the characteristics of this system. we propose the pipelined parallel structure and implement this system into VLSL. Also we evaluate this system and compare with other systems. The processing speed of this system is 550kb/s when dimension is 100. It is possible to use this system at the place of requiring high speed security to enlarge the structure of it.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.6
• /
• pp.1316-1322
• /
• 2005

Specially, though electronic commerce and electron signature technology through internet rose, PKI (Public Key Ifrastructure) is one of technologies. PKI brought several kind of new standards in encryption base technology. In spite of several kind of standardizations consist lively, shortcoming of solutions that apply PKI is expensive and slow. If main interest of encryption technology including PKI is the fast speed and security that improve, this is very serious problem. The various kinds alternatives about these problem are presented. But, we must consider about replace expense and stability etc. still. So, I propose that use suitable encryption policy by method to solve such problem. I improved some problems of existent PKI structure. Subject of this treatise designs and embody communication component could use easily and simply short message communication or simplicity way encryption communication.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.4 no.5
• /
• pp.968-988
• /
• 2010

Anonymous hierarchical identity based encryption (HIBE) is an extension of identity based encryption (IBE) that can use an arbitrary string like an e-mail address for a public key, and it additionally provide the anonymity of identity in ciphertexts. Using the anonymous HIBE schemes, it is possible to construct anonymous communication systems and public key encryption with keyword search. This paper presents an anonymous HIBE scheme with constant size ciphertexts under prime order symmetric bilinear groups, and shows that it is secure under the selective security model. Previous anonymous HIBE schemes were constructed to have linear size ciphertexts, to use composite order bilinear groups, or to use asymmetric bilinear groups that is a special type of bilinear groups. Our construction is the first efficient anonymous HIBE scheme that has constant size ciphertexts and that uses prime order symmetric bilinear groups. Compared to the previous scheme of composite order bilinear groups, ours is ten times faster. To achieve our construction, we first devise a novel cancelable random blinding technique. The random blinding property of our technique provides the anonymity of our construction, and the cancellation property of our technique enables decryption.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.9
• /
• pp.4527-4547
• /
• 2018

Signcryption is a cryptographic primitive that provides authentication (signing) and confidentiality (encrypting) simultaneously at a lower computational cost and communication overhead. With the proposition of certificateless public key cryptography (CLPKC), certificateless signcryption (CLSC) scheme has gradually become a research hotspot and attracted extensive attentions. However, many of previous CLSC schemes are constructed based on time-consuming pairing operation, which is impractical for mobile devices with limited computation ability and battery capacity. Although researchers have proposed pairing-free CLSC schemes to solve the issue of efficiency, many of them are in fact still insecure. Therefore, the challenging problem is to keep the balance between efficiency and security in CLSC schemes. In this paper, several existing CLSC schemes are cryptanalyzed and a new CLSC scheme without pairing based on elliptic curve cryptosystem (ECC) is presented. The proposed CLSC scheme is provably secure against indistinguishability under adaptive chosen-ciphertext attack (IND-CCA2) and existential unforgeability under adaptive chosen-message attack (EUF-CMA) resting on Gap Diffie-Hellman (GDH) assumption and discrete logarithm problem in the random oracle model. Furthermore, the proposed scheme resists the ephemeral secret leakage (ESL) attack, public key replacement (PKR) attack, malicious but passive KGC (MPK) attack, and presents efficient computational overhead compared with the existing related CLSC schemes.

• The KIPS Transactions:PartC
• /
• v.19C no.4
• /
• pp.225-230
• /
• 2012

Since one of weak points of public crypto-systems is to require the verification of public key, identity based crypto-systems were proposed as an alternative. However, such techniques need a private key generator which can be a single point of failure. To improve such weakness, threshold identity-based crypto-systems were proposed. In this paper, we propose a new threshold identity-based encryption scheme which is constructed to extend an identity-based encryption scheme by Cocks. Since the proposed scheme is based on quadratic residues, it has smaller complexity of encryption. And we prove that the proposed scheme is secure against a chosen identity attack.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.7
• /
• pp.3455-3474
• /
• 2018

As a unique form of signed-digit representation, non-adjacent form (NAF) minimizes Hamming weight by removing a stream of non-zero bits from the binary representation of positive integer. Thanks to this strong point, NAF has been used in various applications such as cryptography, packet filtering and so on. In this paper, to improve the NAF conversion speed of the $NAF_w$ algorithm, we propose a new NAF conversion algorithm, called w-bit Shifting Non-Adjacent Form($SNAF_w$), where w is width of scanning window. By skipping some unnecessary bit comparisons, the proposed algorithm improves the NAF conversion speed of the $NAF_w$ algorithm. To verify the excellence of the $SNAF_w$ algorithm, the $NAF_w$ algorithm and the $SNAF_w$ algorithm are implemented in the 8-bit microprocessor ATmega128. By measuring CPU cycle counter for the NAF conversion under various input patterns, we show that the $SNAF_2$ algorithm not only increases the NAF conversion speed by 24% on average but also reduces deviation in the NAF conversion time for each input pattern by 36%, compared to the $NAF_2$ algorithm. In addition, we show that $SNAF_w$ algorithm is always faster than $NAF_w$ algorithm, regardless of the size of w.

• The KIPS Transactions:PartC
• /
• v.11C no.5
• /
• pp.569-576
• /
• 2004

Conventional researches of standard tool validating public key cryptographic algorithm have been studied for the internet environment, not for the mobile internet. It is important to develop the validation tool for establishment of interoperability and convenience of users in mobile internet. Therefore, this paper presents the validation tool of Elliptic Curie Cryptography algorithm that can test if following X9.62 technology standard specification. The validation tool can be applied all information securities using ECDSA, ECKCDSA, ECDH, etc. Moreover, we can en-hace the precision of validation through several experiments and perform the validation tool in the online environment.

• International Journal of Computer Science & Network Security
• /
• v.22 no.6
• /
• pp.212-222
• /
• 2022

There has been a rapid increase in the use of cloud email services. As a result, email encryption has become more commonplace as concerns about cloud privacy and security grow. Nevertheless, this increase in usage is creating the challenge of how to effectively be searching and filtering the encrypted emails. They are popular technologies of solving the issue of the encrypted emails searching through searchable public key encryption. However, the problem of encrypted email filtering remains to be solved. As a new approach to finding and filtering encrypted emails in the cloud, we propose a ciphertext-based encrypted policy attribute-based encryption scheme and keyword search procedure based on hidden policy ciphertext. This feature allows the user of searching using some encrypted emails keywords in the cloud as well as allowing the emails filter-based server toward filter the content of the encrypted emails, similar to the traditional email keyword filtering service. By utilizing composite order bilinear groups, a hidden policy system has been successfully demonstrated to be secure by our dual system encryption process. Proposed system can be used with other scenarios such as searching and filtering files as an applicable method.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.8
• /
• pp.1172-1179
• /
• 2022

This paper describes a design of point scalar multiplier for public-key cryptography based on binary Edwards curves (BEdC). For efficient implementation of point addition (PA) and point doubling (PD) on BEdC, projective coordinate was adopted for finite field arithmetic, and computational performance was improved because only one inversion was involved in point scalar multiplication (PSM). By applying optimizations to hardware design, the storage and arithmetic steps for finite field arithmetic in PA and PD were reduced by approximately 40%. We designed two types of point scalar multipliers for BEdC, Type-I uses one 257-b×257-b binary multiplier and Type-II uses eight 32-b×32-b binary multipliers. Type-II design uses 65% less LUTs compared to Type-I, but it was evaluated that it took about 3.5 times the PSM computation time when operating with 240 MHz. Therefore, the BEdC crypto core of Type-I is suitable for applications requiring high-performance, and Type-II structure is suitable for applications with limited resources.