• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.4203-4225
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• 2014

Fuzzy identity-based cryptography introduces the threshold structure into identity-based cryptography, changes the receiver of a ciphertext from exact one to dynamic many, makes a cryptographic scheme more efficient and flexible. In this paper, we propose the first fuzzy identity-based signcryption scheme in lattice-based cryptography. Firstly, we give a fuzzy identity-based signcryption scheme that is indistinguishable against chosen plaintext attack under selective identity model. Then we apply Fujisaki-Okamoto method to obtain a fuzzy identity-based signcryption scheme that is indistinguishable against adaptive chosen ciphertext attack under selective identity model. Thirdly, we prove our scheme is existentially unforgeable against chosen message attack under selective identity model. As far as we know, our scheme is the first fuzzy identity-based signcryption scheme that is secure even in the quantum environment.

• ETRI Journal
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• 제37권3호
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• pp.512-522
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• 2015

Recent developments in identity-based cryptography (IBC) have provided new solutions to problems related to the security of mobile ad hoc networks (MANETs). Although many proposals to solve problems related to the security of MANETs are suggested by the research community, there is no one solution that fits all. The interdependency cycle between secure routing and security services makes the use of IBC in MANETs very challenging. In this paper, two novel methods are proposed to eliminate the need for this cycle. One of these methods utilizes a key pool to secure routes for the distribution of cryptographic materials, while the other adopts a pairing-based key agreement method. Furthermore, our proposed methods utilize threshold cryptography for shared secret and private key generation to eliminate the "single point of failure" and distribute cryptographic services among network nodes. These characteristics guarantee high levels of availability and scalability for the proposed methods. To illustrate the effectiveness and capabilities of the proposed methods, they are simulated and compared against the performance of existing methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권7호
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• pp.2554-2571
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• 2014

Certificate-based cryptography is a new cryptographic paradigm that provides an interesting balance between identity-based cryptography and traditional public key cryptography. It not only simplifies the complicated certificate management problem in traditional public key cryptography, but also eliminates the key escrow problem in identity-based cryptography. As an extension of the signcryption in certificate-based cryptography, certificate-based signcryption provides the functionalities of certificate-based encryption and certificate-based signature simultaneously. However, to the best of our knowledge, all constructions of certificate-based signcryption in the literature so far have to be based on the costly bilinear pairings. In this paper, we propose a certificate-based signcryption scheme that does not depend on the bilinear pairings. The proposed scheme is provably secure in the random oracle model. Due to avoiding the computationally-heavy paring operations, the proposed scheme significantly reduces the cost of computation and outperforms the previous certificate-based signcryption schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권2호
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• pp.881-896
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• 2016

Certificate-based cryptography is a useful public key cryptographic primitive that combines the merits of traditional public key cryptography and identity-based cryptography. It not only solves the key escrow problem inherent in identity-based cryptography, but also simplifies the cumbersome certificate management problem in traditional public key cryptography. In this paper, by giving a concrete attack, we first show that the certificate-based encryption scheme without bilinear pairings proposed by Yao et al. does not achieve either the chosen-ciphertext security or the weaker chosen-plaintext security. To overcome the security weakness in Yao et al.'s scheme, we propose an enhanced certificate-based encryption scheme that does not use the bilinear pairings. In the random oracle model, we formally prove it to be chosen-ciphertext secure under the computational Diffie-Hellman assumption. The experimental results show that the proposed scheme enjoys obvious advantage in the computation efficiency compared with the previous certificate-based encryption schemes. Without costly pairing operations, it is suitable to be employed on the computation-limited or power-constrained devices.

• ETRI Journal
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• 제45권6호
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• pp.1090-1102
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• 2023

Authenticated multiple key agreement (AMKA) protocols provide participants with multiple session keys after one round of authentication. Many schemes use Diffie-Hellman or authenticated key agreement schemes that rely on hard integer factorizations that are vulnerable to quantum algorithms. Lattice cryptography provides quantum resistance to authenticated key agreement protocols, but the certificate always incurs excessive public key infrastructure management overhead. Thus, a lightweight lattice-based secure system is needed that removes this overhead. To answer this need, we provide a two-party lattice- and identity-based AMKA scheme based on bilateral short integer or computational bilateral inhomogeneous small integer solutions, and we provide a security proof based on the random oracle model. Compared with existing AMKA protocols, our new protocol has higher efficiency and stronger security.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권7호
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• pp.3629-3647
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• 2017

Certificate-based cryptography is a useful public key cryptographic primitive that combines the merits of traditional public key cryptography and identity-based cryptography. It not only solves the key escrow problem inherent in identity-based cryptography, but also simplifies the cumbersome certificate management problem in traditional public key cryptography. So far, four short certificate-based signature schemes have been proposed. However, three of them fail in achieving the existential unforgeability under adaptive chosen-message attacks and the remaining one was not constructed in the normal framework of certificate-based signature. In this paper, we put forward a new short certificate-based signature scheme. The proposed scheme is devised in the normal framework of certificate-based signature and overcomes the security weaknesses in the previous short certificate-based signature schemes. In the random oracle model, we formally prove that it achieves the existential unforgeability against adaptive chosen-message attacks. Performance comparison shows that it is efficient and practical.

• 한국컴퓨터정보학회논문지
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• 제22권9호
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• pp.49-55
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• 2017

Despite the Openflow's switch migration occurs after the channel was established in secure manner (optional), the current cryptography protocol cannot prevent the insider attack as the attacker possesses a valid public/private key pair. There are methods such as the certificate revocation list (CRL) or the online certificate status protocol (OCSP) that tries to revoke the compromised certificate. However, these methods require a management system or server that introduce additional overhead for the communication. Furthermore, these methods are not able to mitigate power abuse of an insider. In this paper, we propose a role-based identity-based cryptography (RB-IBC) that integrate the identity of the node along with its role so the nodes within the network can easily mitigate any role abuse of the nodes. Besides that, by combining with IBC, it will eliminate the need of exchanging certificates and hence improve the performance in a secure channel.

• 융합보안논문지
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• 제15권5호
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• pp.3-8
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• 2015

모바일 클라우드 컴퓨팅 시스템은 일반적으로 데이터 보호와 상호 인증을 위하여 공개키 암호화 기법을 사용하고 있는데 최근 전통적인 공개키 암호화 기술의 변형인 ID-기반 암호화(IBC)가 주목받고 있다. IBC의 증명서-무통제 접근은 클라우드 환경의 동적인 성격에 더 적합하지만, 모바일 장치에 대하여 처리 오버헤드를 최소화하는 보안 프레임워크가 필요하다. 본 논문에서는 모바일 클라우드 컴퓨팅에서의 계층적 ID-기반 암호화(HIBE)의 사용을 제안한다. HIBE는 사용자 인증과 개인키 생성 등의 권한을 위임하여 최상위 공개키 생성기의 업무량을 감소시킬 수 있으므로 모바일 네트워크에 적합하다. 모바일 클라우드 시스템에서 ID-기반 인증과 ID-기반 신분확인 기법을 제안하고, 또한 안전한 데이터처리를 위한 ID-기반 인증 스킴에 대하여 기술하였다. 제안된 스킴은 단방향 해쉬 함수와 XOR 연산으로 설계하여 모바일 사용자를 위한 저 계산 비용을 갖는다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권2호
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• pp.1043-1063
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• 2019

With delegating proxy to process data before outsourcing, data owners in restricted access could enjoy flexible and powerful cloud storage service for productivity, but still confront with data integrity breach. Identity-based data auditing as a critical technology, could address this security concern efficiently and eliminate complicated owners' public key certificates management issue. Recently, Yu et al. proposed an Identity-Based Public Auditing for Dynamic Outsourced Data with Proxy Processing (https://doi.org/10.3837/tiis.2017.10.019). It aims to offer identity-based, privacy-preserving and batch auditing for multiple owners' data on different clouds, while allowing proxy processing. In this article, we first demonstrate this scheme is insecure in the sense that malicious cloud could pass integrity auditing without original data. Additionally, clouds and owners are able to recover proxy's private key and thus impersonate it to forge tags for any data. Secondly, we propose an improved scheme with provable security in the random oracle model, to achieve desirable secure identity based privacy-preserving batch public auditing with proxy processing. Thirdly, based on theoretical analysis and performance simulation, our scheme shows better efficiency over existing identity-based auditing scheme with proxy processing on single owner and single cloud effort, which will benefit secure big data storage if extrapolating in real application.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권12호
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• pp.3261-3273
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• 2013

In the paper, we propose a novel adaptively secure hierarchical identity-based signature scheme from lattices. The size of signatures in our scheme is shortest among the existing hierarchical identity-based signature schemes from lattices. Our scheme is motivated by Gentry et al.'s signature scheme and Agrawal et al.'s hierarchical identity-based encryption scheme.