• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.1
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• pp.45-56
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• 2013

When a signer signs a message, strong designated verifier signature allows the signer to designate a verifier. Only the designated verifier can make sure that the signature is generated by the signer. In addition, no one except the designated verifier can know the signature generated by some signer. In this paper, we propose an identity-based strong designated verifier signature scheme where users' public keys are identities. Our proposed scheme is the first identity-based strong designated verifier scheme from lattices. Naturally, our proposed scheme is secure against quantum computing attacks and has low computational complexity.

• ETRI Journal
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• v.34 no.2
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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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• v.11 no.11
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• pp.5625-5641
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• 2017

Certificateless public key cryptography resolves the certificate management problem in traditional public key cryptography and the key escrow problem in identity-based cryptography. In recent years, some good results have been achieved in speeding up the computation of bilinear pairing. However, the computation cost of the pairing is much higher than that of the scalar multiplication over the elliptic curve group. Therefore, it is still significant to design cryptosystem without pairing operations. A multi-signer universal designated multi-verifier signature scheme allows a set of signers to cooperatively generate a public verifiable signature, the signature holder then can propose a new signature such that only the designated set of verifiers can verify it. Multi-signer universal designated multi-verifier signatures are suitable in many different practical applications such as electronic tenders, electronic voting and electronic auctions. In this paper, we propose a certificateless multi-signer universal designated multi-verifier signature scheme and prove the security in the random oracle model. Our scheme does not use pairing operation. To the best of our knowledge, our scheme is the first certificateless multi-signer universal designated multi-verifier signature scheme.