• 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.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권10호
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• pp.2692-2707
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• 2012

A separable identity-based ring signature scheme has been constructed as a fundamental cryptographic primitive for protecting user privacy. Using the separability property, ring members can be selected from arbitrary domains, thereby, giving a signer a wide range of ways to control privacy. In this paper we propose a generic method to construct efficient identity-based ring signature schemes with various levels of separability. We first describe a method to efficiently construct an identity-based ring signature scheme for a single domain, in which a signer can select ring identities by choosing from identities defined only for the domain. Next, we present a generic method for linking ring signatures constructed for a single domain. Using this method, an identity-based ring signature scheme with a compact structure, supporting multiple arbitrary domains can be designed. We show that our method outperforms the best known schemes in terms of signature size and computational costs, and that the security model based on the separability of identity-based ring signatures, presented in this paper, is highly refined and effective by demonstrating the security of all of the proposed schemes, using a model with random oracles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권5호
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• pp.2792-2810
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• 2017

Forward-secure signature is a specific type of signature, which can mitigate the damage caused by the signing key exposure. Most of the existing forward-secure (identity-based) signature schemes can update users' secret keys at each time period, achieve the existential unforgeability, and resist against classical computer attacks. In this paper, we first revisit the framework of forward-secure identity-based signatures, and aim at supporting flexible key update at multi time period. Then we propose a post-quantum forward-secure identity-based signature scheme from lattices and use the basis delegation technique to provide flexible key update. Finally, we prove that the proposed scheme is strongly unforgeable under the short integer solution (SIS) hardness assumption in the random oracle model.

• Journal of information and communication convergence engineering
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• 제7권1호
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• pp.24-29
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• 2009

Sahai and Waters first introduced the concept of Fuzzy Identity Based Encryption (FIBE) to provide an error-tolerance property for Identity Based Encryption (IBE) in 2005. Yang et al. extended this idea and introduced the concept of Fuzzy Identity Based Signature (FIBS) in 2008, and constructed a FIBS scheme based on Sahai and Waters's FIBE scheme. In this paper, we further formalize the notion and security model of FIBS scheme and propose a new construction of FIBS scheme based on bilinear pairing. The proposed FIBS scheme not only provide shorter public parameters, private key and signature, but also have useful structures which result in more efficient key extraction, signing and verification than that of Yang et al.'s FIBS scheme.

• 정보보호학회논문지
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• 제23권1호
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• pp.45-56
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• 2013

강한 지정된 검증자 서명은 서명자가 검증자를 지정하여 서명을 생성하며, 이렇게 생성된 서명은 지정된 검증자만이 서명자로부터 생성되었는지를 확신할 수 있다. 추가적으로, 지정된 검증자 이외의 어떤 누구도 이렇게 생성된 서명이 어떤 서명자에 의해 생성된 서명인지를 알아낼 수 없다는 특징을 가진다. 본 논문에서 우리는 사용자의 공개키가 ID라는 장점을 가지는 ID 기반의 강한 지정된 검증자 서명 기법을 제안한다. 우리가 제안하는 기법은 ID 기반의 강한 지정된 검증자 서명 분야에서 최초로 래티스에서 설계되었으며, 따라서 양자 컴퓨팅 환경에서도 안전하며 높은 연산 효율성을 가진다.

• ETRI Journal
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• 제34권2호
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• pp.235-244
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• 2012

An identity-based strong designated verifier signature scheme provides restricted verifiability only for a verifier designated by a signer and proper privacy for the signer. In this paper, we show that strong designated verifier signature schemes do not satisfy the self-unverifiability requirement in the sense that not only exposure of the verifier's secret key but also of the signer's secret key enables an attacker to verify signatures, which should have been the exclusive right of the verifier. We also present a generic method to construct a strong identity-based designated verifier signature scheme with self-unverifiability from identity-based key encapsulation and identity-based key sharing schemes. We prove that a scheme constructed from our method achieves unforgeability, non-transferability, and self-unverifiability if the two underlying components are secure. To show the advantage of our method, we present an example that outputs short signatures and we analyze its performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권5호
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• pp.2762-2777
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• 2017

A fuzzy identity based signature (FIBS) scheme allows a signer with identity ${\omega}$ to generate a signature which could be verified under identity ${\omega}^{\prime}$ if and only if ${\omega}$ and ${\omega}^{\prime}$ are within a certain distance of each other as judged by some metric. In this paper, we propose an efficient FIBS scheme from lattice assumption, which can resist quantum-computer attacks. Without using the Bonsai Tree technique, we utilize the lattice basis delegation technique to generate the private key, which has the advantage of keeping the lattice dimension invariant. We also prove that our proposed scheme is existentially unforgeable under an adaptive chosen message and identity attack in the random oracle model. Compared with existing scheme, our proposed scheme is much more efficient, especially in terms of communication overhead. Since our FIBS scheme possesses similar error-tolerance property, it can be well applied in post-quantum communication biometric authentication environments, where biometric identifiers such as fingerprints, voice, iris and gait are used in human identification.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권8호
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• pp.2010-2026
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• 2013

The combination of biometrics and cryptography gains a lot of attention from both academic and industry community. The noisy biometric measurement makes traditional identity based cryptosystems unusable. Also the extraction of key from biometric information is difficult. In this paper, we propose an efficient biometric identity based signature scheme (Bio-IBS) that makes use of fuzzy extractor to generate the key from a biometric data of user. The component fuzzy extraction is based on error correction code. We also prove that the security of suggested scheme is reduced to computational Diffie-Hellman (CDH) assumption instead of other strong assumptions. Meanwhile, the comparison with existing schemes shows that efficiency of the system is enhanced.

• 대한수학회보
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• 제46권4호
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• pp.743-769
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• 2009

An ID-based DNF signature scheme is an ID-based signature scheme with an access structure which is expressed as a disjunctive normal form (DNF) with literals of signer identities. ID-based DNF signature schemes are useful to achieve not only signer-privacy but also a multi-user access control. In this paper, we formally define a notion of a (non-interactive) ID-based DNF signature and propose the first noninteractive ID-based DNF signature schemes that are secure under the computational Diffie-Hellman and subgroup decision assumptions. Our first scheme uses random oracles, and our second one is designed without random oracles. To construct the second one, we use a novel technique that converts a non-interactive witness indistinguishable proof system of encryption of one bit into a corresponding proof system of encryption of a bit-string. This technique may be of independent interest. The second scheme straightforwardly yields the first ID-based ring signature that achieves anonymity against full key exposure without random oracles. We finally present two extensions of the proposed ID-based DNF signature schemes to support multiple KGCs and different messages.

• 문화기술의 융합
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• 제7권3호
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• pp.453-462
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• 2021

최근 전자서명법 개정으로 인해 공인인증서(현. 공동인증서) 지위가 만료됨에 따라 전자서명 기반의 공인인증서도 주민등록번호 대체수단에서 지휘가 상실되었다. 이로 인해 공인인증기관들은 방송통신위원회로부터 주민등록번호 대체수단 기반의 본인확인기관 지정심사를 통해 본인확인서비스 제공 기관으로 최근 지정받은 바 있다. 하지만, 기존의 주민등록번호 대체수단인 아이핀, 휴대폰, 그리고 신용카드들과 달리 인증서 발급 신청자의 신원확인 절차가 기존 대체수단들과는 상이한 부분이 존재하고 있다. 특히, 발급 신청자의 신원을 등록대행기관이 수행하고 있다. 본 연구에서는 전자서명 기반의 본인확인서비스 제공 시 대체수단 발급 과정에서 신원확인, 허무인 확인, 신원보증인 확인 등에 대한 개선방안들을 제안한다. 제안한 방안은 전자서명 기반의 본인확인서비스에 적용함으로써 이용자 개인정보보호와 보편·타당하고 안전한 본인확인서비스 제공이 가능함을 알 수 있다.