Two new identity-based threshold ring signature schemes

The ring signature can guarantee the signer’s anonymity. Most proposed ring signature schemes have two problems: One is that the size of ring signature depends linearly on the ring size, and the other is that the signer can shift the blame to victims because of the anonymity. Some authors have studied the constant-size ring signature and deniable ring signature to solve these two problems. This paper shows that an identity-based ring signature scheme with constant size has some security problems by using an insecure accumulator and its verification process does not include the message m. Then we combine the concepts of “constant-size” and “deniable” to form an id-based deniable ring signature with constant-size signature. The new scheme with constant-size signature length is proposed based on an improved accumulator from bilinear pairings and it solves the problem of anonymity abuse.

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Identity-Based Linkable Ring Signature on NTRU Lattice

Security and Communication Networks ◽

10.1155/2021/9992414 ◽

2021 ◽

Vol 2021 ◽

pp. 1-17

Author(s):

Yongli Tang ◽

Feifei Xia ◽

Qing Ye ◽

Mengyao Wang ◽

Ruijie Mu ◽

...

Keyword(s):

Random Oracle Model ◽

Random Oracle ◽

Small Integer ◽

Rejection Sampling ◽

Signature Schemes ◽

Ring Signature ◽

Storage Overhead ◽

Signature Generation ◽

Identity Based ◽

And Storage

Although most existing linkable ring signature schemes on lattice can effectively resist quantum attacks, they still have the disadvantages of excessive time and storage overhead. This paper constructs an identity-based linkable ring signature (LRS) scheme over NTRU lattice by employing the technologies of trapdoor generation and rejection sampling. The security of this scheme relies on the small integer solution (SIS) problem on NTRU lattice. We prove that this scheme has unconditional anonymity, unforgeability, and linkability under the random oracle model (ROM). Through the performance analysis, this scheme has a shorter size of public/private keys, and when the number of ring members is small (such as N ≤ 8 ), this scheme has a shorter signature size compared with other existing latest lattice-based LRS schemes. The computational efficiency of signature has also been further improved since it only involves multiplication in the polynomial ring and modular operations of small integers. Finally, we implemented our scheme and other similar schemes, and it is shown that the time for the signature generation and verification of this scheme decreases roughly by 44.951% and 33.503%, respectively.

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