Identity-based Threshold Research Articles

Identity-based threshold (multi) signature with private accountability for privacy-preserving blockchain

Identity-based threshold signature (IDTHS) allows a threshold number of signers to generate signatures to improve the deterministic wallet in the blockchain. However, the IDTHS scheme cannot determine the identity of malicious signers in case of misinformation. To solve this challenge, we propose an identity-based threshold (multi) signature with private accountability (for short AIDTHS) for privacy-preserving blockchain. From the public perspective, AIDTHS is completely private and no user knows who participated in generating the signature. At the same time, when there is a problem with the transaction, a trace entity can trace and be accountable to the signers. We formally define the syntax and security model of AIDTHS. To address the issue of identifying malicious signers, we improve upon traditional identity-based threshold signatures by incorporating zero-knowledge proofs as part of the signature and leveraging a tracer holding tracing keys to identify all signers. Additionally, to protect the privacy of signers, the signature is no longer achievable by anyone, which requires a combiner holding the keys to produce a valid signature. We give a concrete construction of AIDTHS and prove its security. Finally, we implement the AIDTHS scheme and compare it with existing schemes. The key distribution algorithm of AIDTHS takes 34.60 μs and the signature algorithm takes 13.04 ms. The verification algorithm takes 1 s, which is one-third of the time the TAPS scheme uses.

Fully distributed identity-based threshold signatures with identifiable aborts

Fully distributed identity-based threshold signatures with identifiable aborts

Identity-based threshold proxy re-encryption scheme from lattices and its applications

Identity-based threshold proxy re-encryption scheme from lattices and its applications

Identity-based threshold group signature scheme based on multiple hard number theoretic problems

We introduce in this paper a new identity-based threshold signature (IBTHS) technique, which is based on a pair of intractable problems, residuosity and discrete logarithm. This technique relies on two difficult problems and offers an improved level of security relative to an individual hard problem. The majority of the denoted IBTHS techniques are established on an individual difficult problem. Despite the fact that these methods are secure, however, a prospective solution of this sole problem by an adversary will enable him/her to recover the entire private data together with secret keys and configuration values of the associated scheme. Our technique is immune to the four most familiar attack types in relation to the signature schemes. Enhanced performance of our proposed technique is verified in terms of minimum cost of computations required by both of the signing algorithm and the verifying algorithm in addition to immunity to attacks.

Identity-Based Threshold Decryption Scheme from Lattices under the Standard Model

Identity-Based Threshold Decryption Scheme from Lattices under the Standard Model

Efficient identity-based threshold decryption scheme from bilinear pairings

Using Shamir’s secret sharing scheme to indirectly share the identity-based private key in the form of a pairing group element, we propose an efficient identity-based threshold decryption scheme from pairings and prove its security in the random oracle model. This new paring-based scheme features a few improvements compared with other schemes in the literature. The two most noticeable features are its efficiency, by drastically reducing the number of pairing computations, and the ability it gives the user to share the identity-based private key without requiring any access to a private key generator. With the ability it gives the user to share the identity-based private key, our ID-based threshold decryption (IBTD) scheme, the second of its kind, is significantly more efficient than the first scheme, which was developed by Baek and Zheng, at the expense of a slightly increased ciphertext length. In fact, our IBTD scheme tries to use as few bilinear pairings as possible, especially without depending on the suite of Baek–Zheng secret sharing tools based on pairings.

A New ID-based Threshold Ring Signcryption without Random Oracles

Signcryption is a cryptographic primitive which could provide authentication and confidentiality simultaneously with a computational cost lower than signing and encryption respectively, while the ring signcryption has anonymity in addition to authentication and confidentiality. In order to design an identity-based threshold ring signcryption, this paper presented an efficient identity-based threshold ring signcryption scheme without random oracles by means of secret sharing and bilinear pairing technique, and gave security analysis of the scheme. In the last, we proved this scheme satisfied indistinguishability against adaptive chosen ciphertext attacks and existential unforgeability against adaptive chosen message and identity attacks in terms of the hardness of DBDH problem and CDH problem.

Lattice-based identity-based resplittable threshold public key encryption scheme

Threshold public key encryption is a cryptographic primitive where a secret key of an organization is distributed among special members called decryption servers (insiders) and a certain threshold number of insiders must cooperate to decrypt any ciphertext. Threshold public key encryption with an additional randomized algorithm Tsplit is called resplittable threshold public key encryption (RTPKE). Cryptographic primitive RTPKE was introduced by Hanaoka et al. [Generic construction of chosen ciphertext secure proxy re-encryption, in CT-RSA, San Francisco, CA, USA, LNCS, O. Dunkelman, ed., Springer-Verlag, Heidelberg, 2012, pp. 349–364] in a generic construction of chosen ciphertext attack secure proxy re-encryption scheme. In MIST 2013 conference Singh et al. [Lattice based efficient threshold public key encryption scheme, J. Wirel. Mob. Netw. Ubiquitous Comput. Dependable Appl. (JoWUA) 4(4) (2013), pp. 93–107] presented lattice-based RTPKE scheme based on Regev's LWE [On lattices, learning with errors, random linear codes, and cryptography, in STOC, Baltimore, MD, USA, H.N. Gabow and R. Fagin, eds., ACM, University of Wales, Cardiff, 2005, pp. 84–93] assumption. In this paper, we propose lattice-based RTPKE scheme in the identity-based setting.

Two new identity-based threshold ring signature schemes

This paper presents two new identity-based threshold ring signature schemes. With these schemes, any group of t entities spontaneously conscript arbitrarily n−t entities to generate a publicly verifiable t-out-of-n signature on behalf of the group of n members, yet the actual signers remain anonymous. The schemes are proven to be existentially unforgeable against adaptive chosen message and identity attacks (EUF-IBTRS-CMIA) and unconditional signer ambiguity under the random oracle model.

Identity-based threshold ring signcryption from pairing

This paper presents an identity-based threshold ring signcryption scheme. With this technique, any group of t entities can choose n - t entities to generate a t-out-of-n signcryption on behalf of the group of n members, yet the actual signcrypters remain anonymous. The scheme is proven to be indistinguishable against adaptive chosen ciphertext attacks, existentially unforgeable against adaptive chosen message and identity attacks, and unconditional signcrypter ambiguity under the random oracle model. To the best of authors' knowledge, the scheme is the first security ID-based threshold ring signcryption scheme.

Efficient identity-based threshold signature scheme from bilinear pairings in standard model

We propose a new identity-based threshold signature (IBTHS) scheme from bilinear pairings enjoying the following advantages in efficiency, security and functionality. The round-complexity of the threshold signing protocol is optimal since each party pays no other communication cost except broadcasting one single message. The computational complexity of the threshold signing procedure is considerably low since there appears no other time-consuming pairing except two pairings for verifying each signature shares. The communication channel requirement of the threshold signing procedure is the lowest since the broadcast channel among signers is enough. It is provably secure with optimal resilience in the standard model. It is the private key associated with an identity rather than a private key of the private key generator (PKG) that is shared among signature generation servers.

Identity-based threshold ring signature scheme with constant signature size

Identity-based threshold ring signature scheme with constant signature size

On Access Security in Cloud Computing

Currently cloud computing brings along a lot of positive changes to our life, and at the same time it does lead to a lot of security concerns. In order to overcome these concerns, in this paper we first introduce system under study; second, we reduce the group authentication steps for key distribution by means of TPM-based certificates; third, we leverage the identity-based threshold cryptography to avoid single-point-of-failure; last, we design experiments to test our scheme and give related explanations.

Comparing General Paradigms on Data Secrecy Protection for Outsourced Files in Mobile Cloud Computing

The data secrecy of outsourced files in cloud server should be protected even though cloud servers are untrustworthy. In this paper, we extensively analyze the techniques on data privacy protection for secure cloud storage. We propose and compare several general paradigms on data secrecy protection including ID-based scheme, CLPKCbased scheme, key-escrow-based scheme, ID-based threshold decryption scheme, and trusted third party based scheme. After the analysis and comparison, ID-based threshold decryption scheme has the most advantages with respect to no constraints such as certificate and key escrow.

User-oriented key management scheme for content protection in OPMD environment

In this paper, we propose a key management scheme for content protection in the OPMD (One Person Multi Device) environment where one user owns multiple devices. IBTD (ID-Based Threshold Decryption) was applied for the proposed scheme, and this uses the user IDs and the device IDs as their public key. It is the key management scheme that can decrypt the encrypted content only when more than t secret sharing values are combined among the n secret sharing values generated by the contents server. Our scheme enables the users to use their own contents anytime and anywhere on any device that they own. For the contents server, it enables an effective key management which is user-oriented, not device-oriented.

Cryptanalysis and Improvement of an ID-Based Threshold Signcryption Scheme

Signcryption can realize the function of encryption and signature in a reasonable logic step, which can lower computational costs and communication overheads. In 2008, Fagen Li et al. proposed an efficient secure id-based threshold signcryption scheme. The authors declared that their scheme had the attributes of confidentiality and unforgeability in the random oracle model. In this paper, we show that scheme is insecure against malicious attackers and give our attacker method to forge the ciphertext. Following our method, any malicious attacker can forge a valid message in their scheme. Further, we propose a probably-secure improved scheme to correct the vulnerable and give the unforgeability and confidentiality of our improved scheme under the existing security assumption.

Cryptanalysis and Improvement of Selvi et al.’s Identity-Based Threshold Signcryption Scheme

Signcryption can realize the function of encryption and signature in a reasonable logic step, which can lower computational costs and communication overheads. In 2008, S. S. D. Selvi et al. proposed an identity-based threshold signcryption scheme. In this paper, we show that the threshold signcryption scheme of S. S. D. Selvi et al. is vulnerable if the attacker can replaces the group public key. Then we point out that the receiver uses the senders’ public key without any verification in the unsigncrypt stage cause this attack. Further, we propose a probably-secure improved scheme to correct the vulnerable and give the unforgeability and confidentiality of our improved scheme under the existing security assumption.

Secure Identity-based Threshold Broadcast Encryption in the Standard Model

The general threshold broadcast encryption is not suitable for the networks with the constraints of computation and energy. In this paper, two constructions of the proper threshold broadcast encryption to these networks are proposed. In the proposed schemes, any user can dynamically join the system as a possible recipient, and the sender can dynamically choose the set of recipients S and the threshold value t . The new schemes achieve constant size private keys and O ( n-t )-size ciphertexts. In addition, these schemes achieve full security in the standard model. Finally, we also show that they are provable security under n +1-Weak Decision Bilinear Diffie-Hellman Exponent ( n +1-wDBDHE) assumption and the static assumptions respectively.

Identity-based threshold decryption on access structure

For the applied limitation of the existing threshold decryption schemes based on the (t, n) structure, an identity-based threshold decryption scheme which can be applied on the access structure is proposed through designing a special distribution algorithm of the private key shares. The generation and distribution of private key shares, the encryption, the decryption and the combination are introduced in detail. The validity and security of the scheme are proved and analyzed. Comparisons with the existing schemes show that the proposed scheme is more flexible.

ID-based bidirectional threshold proxy re-signature

Based on Shao et al's ID-based proxy re-signature,an ID-based bidirectional threshold proxy re-signature scheme in the standard model was presented in this paper.The scheme eliminated the cost of restoring and managing certificates,and solved the difficult problem of excessive rights of the proxy in the proxy re-signature scheme.The scheme can tolerate tn/2 malicious proxies.This scheme proves to be robust and secure against the existential forgery under the adaptive chosen identity and message attacks,under the computation Diffie-Hellman assumption.