• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1994.11a
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• pp.35-44
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• 1994

We propose an undeniable digital signature scheme which is practical since it has less computation and communication overhead than Chaum's one. We expect that this protocol be useful to develop secure systems such as electronic contract system, electronic mail system and electronic cash system.

• Journal of applied mathematics & informatics
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• v.31 no.3_4
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• pp.425-441
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• 2013

In literature, several strong designated verifier signature (SDVS) schemes have been devised using elliptic curve bilinear pairing and map-topoint (MTP) hash function. The bilinear pairing requires a super-singular elliptic curve group having large number of elements and the relative computation cost of it is approximately two to three times higher than that of elliptic curve point multiplication, which indicates that bilinear pairing is an expensive operation. Moreover, the MTP function, which maps a user identity into an elliptic curve point, is more expensive than an elliptic curve scalar point multiplication. Hence, the SDVS schemes from bilinear pairing and MTP hash function are not efficient in real environments. Thus, a cost-efficient SDVS scheme using elliptic curve cryptography with pairingfree operation is proposed in this paper that instead of MTP hash function uses a general cryptographic hash function. The security analysis shows that our scheme is secure in the random oracle model with the hardness assumption of CDH problem. In addition, the formal security validation of the proposed scheme is done using AVISPA tool (Automated Validation of Internet Security Protocols and Applications) that demonstrated that our scheme is unforgeable against passive and active attacks. Our scheme also satisfies the different properties of an SDVS scheme including strongness, source hiding, non-transferability and unforgeability. The comparison of our scheme with others are given, which shows that it outperforms in terms of security, computation cost and bandwidth requirement.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.1
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• pp.78-87
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• 2009

An attribute-based signature scheme is a signature scheme where a signer's private key is associate with an attribute set and a signature is associated with an access structure. Attribute-based signature schemes are useful to provide anonymity and access control for role-based systems and attribute-based systems where an identity of object is represented as a set of roles or attributes. In this paper, we formally define the definition of attribute-based signature schemes and propose the first efficient attribute-based signature scheme that requires constant number of pairing operations for verification where a policy is represented as a disjunctive normal form (DNF). To construct provably secure one, we introduce a new interactive assumption and prove that our construction is secure under the new interactive assumption and the random oracle model.

• ETRI Journal
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• v.38 no.2
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• pp.397-404
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• 2016

In group-oriented applications, it is often required to verify a group of signatures/messages. The individual verification of signed messages in such applications comes at a high cost in terms of computations and time. To improve computational efficiency and to speed up the verification process, a batch verification technique is a good alternative to individual verification. Such a technique is useful in many real-world applications, such as mail servers, e-commerce, banking transactions, and so on. In this work, we propose a new, efficient identity-based signature (IDS) scheme supporting batch verifications. We prove that the proposed IDS scheme and its various types of batch verifications is tightly related to the Computational Diffie.Hellman problem under a random oracle paradigm. We compare the efficiency of the proposed scheme with related schemes that support batch verifications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.11
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• pp.967-969
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• 2013

In this paper, we propose an efficient mult-signature scheme based on a bilinear mapping for shared data in the cloud and prove the security of the proposed scheme using the difficulty of the computational Diffie-Hellman problem. For verification, the scheme is using the sum of the hash values of stored data rather than the entire data, which makes it feasible to reduce the size of the downloaded data.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.1
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• pp.39-46
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• 2003

We propose a quantum signature scheme with message recovery implemented by a symmetrical quantum key cryptosystem and Creenberger-Horne-Zeilinger(CHZ) triplet states. The suggested scheme relies on the availability of an arbitrator and can be divided into two schemes . one is using a public board and the other is not. The two schemes give us the confidentiality of a message and the higher efficiency in transmission. We propose a quantum signature scheme with message recovery using Greenberger-Home-Zeilinger(GHZ) triplet states.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.7_8
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• pp.417-425
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• 2003

We propose an efficient one-time signature scheme for stream authentication by improving HORS. When one-time signatures are used for authenticating live streams, one of the most serious drawbacks is that its large signature size yields high communication overhead. Compared with the previous one-time signature schemes, proposed scheme has the smallest signature size. Moreover, verification overhead is very low. Compared with the previous schemes for stream authentication, signing overhead of our scheme is larger than that of HORS but much lower than those of BiBa or Powerball. Moreover, signing operation can be trivially parallelized without any additional risk because it does not require sharing of the secret key between distributed servers.

• Journal of Korea Multimedia Society
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• v.6 no.3
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• pp.518-526
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• 2003

According to the development of mobile communications, the future mobile communication systems are expected to provide high quality multimedia service to users. Therefore, many technical factors we needed in these systems. Especially the confidentiality and the security would be obtained through the introduction of the security for mobile communications. In this paper, we propose an efficient Proxy-Signcryption scheme, which can be performed digital signature and encryption by using the proxy agent who has more computational power under mobile communications environment. The proposed scheme provides non-repudiation and prevents creating illegal signature by the origin and proxy agent in a phase of proxy signature processing. This scheme also keeps the confidentiality and the security in mobile communication by means of confirming the signature by right receiver.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.691-696
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• 2010

The main idea is to protect the signer of a document against the document being digitally distributed without the cooperation of signer. This paper proposes a new scheme of undeniable signature, which is so effective and improved D. Chaum's scheme. And our scheme which is zero-knowledge proved by using one-way function and partition - selection method, shows that its communication(challenge-response) only needs much fewer times during the confirmation protocol and disavowal protocol respectively, being very useful for wireless network environment. In the meantime our scheme allows the verifier to verify that the signature is valid, while the signer doesn't know the original message and the signature, to preserve the privacy of the verifier.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.8
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• pp.2083-2100
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• 2023

The rise of Industry 5.0 has led to a smarter and more digital way of doing business, but with it comes the issue of user privacy and security. Only when privacy and security issues are addressed, will users be able to transact online with greater peace of mind. Thus, to address the security and privacy problems associated with industry blockchain technology, we propose a privacy protection scheme for online financial transactions based on verifiable ring signatures and blockchain by comparing and combining the unconditional anonymity provided by ring signatures with the high integrity provided by blockchain technology. Firstly, we present an algorithm for verifying ring signature based on distributed key generation, which can ensure the integrity of transaction data. Secondly, by using the block chain technique, we choose the proxy node to send the plaintext message into the block chain, and guarantee the security of the asset transaction. On this basis, the designed scheme is subjected to a security analysis to verify that it is completely anonymous, verifiable and unerasable. The protection of user privacy can be achieved while enabling online transactions. Finally, it is shown that the proposed method is more effective and practical than other similar solutions in performance assessment and simulation. It is proved that the scheme is a safe and efficient online financial transaction ring signature scheme.