scholarly journals Key Protected Deputy Signature Scheme against the Deputy Signing Key Exposure

Author(s):  
Jianhong Chen ◽  
Kun Yu ◽  
Wenhao Wang

Key exposure is very harmful to a cryptographic system. To decrease the loss from the deputy signing key vulnerability in identity-based proxy signature systems, we propose the method of key protected deputy signature (IBKPDS) using the method of parallel key insulation. The proposed IBKPDS is based on identities and is shown to be secure with the cryptographic proof. In the proof, there is no random oracle. In an IBKPPS crypto-system, a user stores his short-lived deputy signing key by himself and saves two long-lived keys in two heavily guarded boxes respectively. The derived IBKPDS cryptographic system is heavily key-separated. A thief who wants to obtain crucial information can not corrupt the IBKPDS when he get only one long-lived key. In addition, the user can change the short-lived deputy signing keys frequently at low risk.

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Congge Xie ◽  
Jian Weng ◽  
Jinming Wen

In 2014, a new security definition of a revocable identity-based signature (RIBS) with signing key exposure resistance was introduced. Based on this new definition, many scalable RIBS schemes with signing key exposure resistance were proposed. However, the security of these schemes is based on traditional complexity assumption, which is not secure against attacks in the quantum era. Lattice-based cryptography has many attractive features, and it is believed to be secure against quantum computing attacks. We reviewed existing lattice-based RIBS schemes and found that all these schemes are vulnerable to signing key exposure. Hence, in this paper, we propose the first lattice-based RIBS scheme with signing key exposure resistance by using the left-right lattices and delegation technology. In addition, we employ a complete subtree revocation method to ensure our construction meeting scalability. Finally, we prove that our RIBS scheme is selective-ID existentially unforgeable against chosen message attacks (EUF-sID-CMA) under the standard short integer solutions (SIS) assumption in the random oracle model.


2021 ◽  
Vol 15 (1) ◽  
pp. 117-137
Author(s):  
Salome James ◽  
Gowri Thumbur ◽  
Vasudeva Reddy P.

In many real-world situations, signature schemes with message recovery plays a very important role to minimize the bandwidth for efficient communications. A proxy signature scheme is a kind of digital signature scheme that allows an original signer to designate his/her signing capacity to a proxy signer. The proxy signer generates a signature on a message on behalf of the original signer. Such signatures are very useful in various applications where the delegation rights is quite common, especially in distributed systems and grid computing. This paper presents a pairing-free proxy signature with message recovery scheme that integrates the advantages of proxy signatures and message recovery in identity based setting. This scheme improves the computational and communicational efficiency due to pairing-free and message recovery features. The proposed scheme is proven secure in the random oracle model under the hardness assumption of the ECDLP. The comparison results shows that the proposed scheme is superior to the related works from the aspect of security and performance.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Quanrun Li ◽  
Chingfang Hsu ◽  
Debiao He ◽  
Kim-Kwang Raymond Choo ◽  
Peng Gong

With the rapid development of quantum computing and quantum information technology, the universal quantum computer will emerge in the near decades with a very high probability and it could break most of the current public key cryptosystems totally. Due to the ability of withstanding the universal quantum computer’s attack, the lattice-based cryptosystems have received lots of attention from both industry and academia. In this paper, we propose an identity-based blind signature scheme using lattice. We also prove that the proposed scheme is provably secure in the random oracle model. The performance analysis shows that the proposed scheme has less mean value of sampling times and smaller signature size than previous schemes. Thus, the proposed scheme is more suitable for practical applications.


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