scholarly journals Strong Designated Verifier Signature Scheme with Undeniability and Strong Unforgeability in the Standard Model

2019 ◽  
Vol 9 (10) ◽  
pp. 2062
Author(s):  
Xiaodong Yang ◽  
Guilan Chen ◽  
Ting Li ◽  
Rui Liu ◽  
Meiding Wang ◽  
...  
Keyword(s):  
Standard Model ◽  
Signature Scheme ◽  
Signature Schemes ◽  
Private Key ◽  
Random Oracles ◽  
Computational Overhead ◽  
The Standard Model ◽  
Designated Verifier ◽  
Designated Verifier Signature ◽  
Strong Unforgeability

Strong designated verifier signature can provide an efficient way to protect the identity privacy of the signer and the integrity of the data transmitted over the public channel. These characteristics make it very useful in outsourcing computing, electronic voting, electronic bidding, electronic auction and other fields. However, most strong designated verifier signature schemes are unable to identify the real signature generator when the signer and the designated verifier dispute a signature. In addition, the existing strong designated verifier signature schemes in the standard model rarely satisfy strong unforgeability, and thus cannot prevent the attacker from forging a valid signature on any previously signed message. Therefore, designing a strong designated verifier signature scheme without random oracles that satisfies strong unforgeability and undeniability is very attractive in both practice and theory. Motivated by these concerns, we design the first undeniable strong designated verifier signature scheme without random oracles, in which the arbiter can independently perform the judgment procedure to prove whether a controversial signature is generated by the signer or the designated verifier. Under standard assumptions, the scheme is proved to be strongly unforgeable in standard model. Furthermore, it not only achieves non-transferability and privacy of the signer’s identity but also satisfies the undeniable property of traditional digital signature schemes. Performance analysis results show that the length of the signer’s private key, the designated verifier’s private key and signature length are 40 bits, 40 bits and 384 bits, respectively. Compared with he related schemes, the proposed scheme has higher performance in signature length, private key size and computational overhead. Finally, we show how to apply it to implement outsourcing computation in cloud computing.

scholarly journals Strongly Unforgeable Ring Signature Scheme from Lattices in the Standard Model

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
Geontae Noh ◽  
Ji Young Chun ◽  
Ik Rae Jeong
Keyword(s):  
Standard Model ◽  
Signature Scheme ◽  
Signature Schemes ◽  
Ring Signature ◽  
Arbitrary Ring ◽  
Computational Overhead ◽  
The Standard Model ◽  
First Time ◽  
Strong Unforgeability

In a ring signature scheme, a user selects an arbitrary ring to be able to sign a message on behalf of the ring without revealing the signer’s identity. Whistle-blowers especially find this useful. To date, various ring signature schemes have been proposed, all considered to be secure as existentially unforgeable with respect to insider corruption; that is, an adversary who chooses ring-message pairs for which he requests signatures, corrupts honest users, and obtains their signing keys can not produce forgeries for new ring-message pairs. Lattice-based ring signature schemes offer lower computational overhead and security from quantum attacks. In this paper, we offer a lattice-based scheme. We begin by showing that the existing ring signature schemes are not sufficiently secure, because existential unforgeability still permits a signer to potentially produce a new signature on previously signed messages. Furthermore, we show that existing ring signature schemes from lattices are not even existentially unforgeable with respect to insider corruption. We then improve previous schemes by applying, for the first time, the concept of strong unforgeability with respect to insider corruption to a ring signature scheme in lattices. This offers more security than any previous ring signature scheme: adversaries cannot produce new signatures for any ring-message pair, including previously signed ring-message pairs.

scholarly journals Attacks on One Designated Verifier Proxy Signature Scheme

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Baoyuan Kang
Keyword(s):  
Standard Model ◽  
Random Oracle Model ◽  
Random Oracle ◽  
Proxy Signature ◽  
Signature Scheme ◽  
Signature Schemes ◽  
Random Oracles ◽  
The Standard Model ◽  
New Construction ◽  
Designated Verifier

In a designated verifier proxy signature scheme, there are three participants, namely, the original signer, the proxy signer, and the designated verifier. The original signer delegates his or her signing right to the proxy signer, then the proxy signer can generate valid signature on behalf of the original signer. But only the designated verifier can verify the proxy signature. Several designated verifier proxy signature schemes have been proposed. However, most of them were proven secure in the random oracle model, which has received a lot of criticism since the security proofs in the random oracle model are not sound with respect to the standard model. Recently, by employing Water's hashing technique, Yu et al. proposed a new construction of designated verifier proxy signature. They claimed that the new construction is the first designated verifier proxy signature, whose security does not rely on the random oracles. But, in this paper, we will show some attacks on Yu et al.'s scheme. So, their scheme is not secure.

Key Replacement Attack on Two Certificateless Signature Schemes without Random Oracles

2010 ◽  
Vol 439-440 ◽  
pp. 1606-1611 ◽  
Author(s):  
Qi Xia ◽  
Chun Xiang Xu ◽  
Yong Yu
Keyword(s):  
Standard Model ◽  
Public Key ◽  
Signature Scheme ◽  
Signature Schemes ◽  
The Public ◽  
Random Oracles ◽  
The Standard Model ◽  
Replacement Attack ◽  
Certificateless Signature

Liu et al. proposed the first certificateless signature scheme without random oracles in 2007. However, Xiong et al. showed that Liu et al.'s scheme is insecure against a malicious-but-passive KGC attack and proposed an improved scheme. In ISA 2009, Yuan et al. also proposed a new certificateless signature scheme without random oracles. Although they claimed that the two schemes are secure in the standard model, this paper shows that both Xiong et al.'s improved scheme and Yuan et al.'s new scheme are vulnerable to key replacement attack, where an adversary, obtaining a signature on a message and replacing the public key of a signer, can forge valid signatures on the same message under the replaced public key. We also give the corresponding modifications of the two schemes to resist key replacement attack.

Some Thoughts on Strong Unforgeability in Ring Signature Schemes

2012 ◽  
Vol 457-458 ◽  
pp. 773-779
Author(s):  
Chen Wang
Keyword(s):  
Standard Model ◽  
Signature Scheme ◽  
Signature Schemes ◽  
Ring Signature ◽  
Modified Method ◽  
Ring Signatures ◽  
The Standard Model ◽  
Strong Unforgeability

A signature scheme is strongly unforgeable if the adversary cannot produce a new signature even on a queried message. Some methods have been proposed to enhance some regular signatures. However, if applied to ring signatures, such methods will break the anonymity, which is the soul of ring signatures. We introduce a modified method which can achieve both strong unforgeability and anonymity in the standard model. Applying this method to Shacham-Waters scheme, we get the first ring signature with strong unforgeability in the stand model.

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