Randomization enhanced Chaum's blind signature scheme

A blind signature enables a user to obtain signatures on any message from an authority who cannot acquire any information on the message being signed. A blind ring signature scheme is designed as a ring signature scheme with the blindness property. The scheme allows any member of a group anonymously sign a message on behalf of the group. Also, the user with the message can blind it before transmitting to the group. At Asiacrypt 2010, Rückert constructed the first blind signature scheme using ideal lattices. Recently, Zhang, Jiang and Zheng, and Alkadri, Bansarkhani and Buchmann proposed two improved blind signature schemes based on the SIS problem and the Ring SIS problem in 2018 and 2020, respectively. At WISA 2019, motivated by these blind signature schemes, Le, Duong and Susilo constructed the first lattice-based blind ring signature scheme provably secure under the hardness assumption of the SIS problem in random oracle model. In this paper, we show that Rückert’s scheme, Alkadri-Bansarkhani-Buchmann scheme and Zhang-Jiang-Zheng scheme, and Le-Duong-Susilo scheme do not achieve blindness, i.e. the signer can link a valid message-signature pair after interacting with various users. We show that the cause of vulnerabilities of the blind schemes is that the blinding factors to hide real messages being signed are exposed by specific algebraic relations in the underlying rings. To hide the blinding factors, we use homomorphic encryption schemes. Finally, we propose a generic construction from a semantically secure homomorphic encryption scheme and a one-more unforgeable blind signature scheme that does not achieve blindness to a new blind signature scheme that achieves blindness as well as one-more unforgeability.

An efficient provably secure identity-based blind signature (IBBS) scheme based on bilinear pairings is proposed. Assuming the intractability of the q-Strong Diffie-Hellman problem, our IBBS is unforgeable under adaptive chosen-message and ID attack. Because of avoiding using the inefficient MapToPoint function, our IBBS can offer advantages in runtime over the schemes available. Based on this ID-based blind signature scheme, we describe the first ID-based threshold blind signature (TBS) and show that it has security properties of unforgeability and robustness.

An efficient provably secure identity-based blind signature (IBBS) scheme based on bilinear pairings is proposed. Assuming the intractability of the q-Strong Diffie-Hellman problem, our IBBS is unforgeable under adaptive chosen-message and ID attack. Because of avoiding using the inefficient MapToPoint function, our IBBS can offer advantages in runtime over the schemes available. Based on this ID-based blind signature scheme, we describe the first ID-based threshold blind signature (TBS) and show that it has security properties of unforgeability and robustness.

Blind signature is a digital signature technology that enables the signature requester to obtain the valid signature of the signer without revealing the identity and content of the message to the signer. It is widely used in electronic cash, electronic voting and other fields. The message recovery technology is a technology that can hide the message in the signature, and only pass the signature without passing the message when it is delivered. In this paper, a blind signature scheme based on certificateless message recovery is proposed based on the combination of blind signature and message recovery technology, and based on certificateless public key cryptosystem. The signer can sign the blinded message under the certificateless cryptosystem, and the final blind signature result can only transmit the signature to reduce the conmmunication bandwidth. Security analysis shows that the scheme satisfies correctness, blindness, and unforgeability.KeywordsCertificatelessBlind signatureMessage recovery

Electronic voting is an alternative mechanism of ballot based voting which empowers voters to cast their secret and secure vote electronically over a public channel. Many onward-thinking countries are adopting the electronic voting system to upgrade their election process. E-voting system is more complicated to construct. Thus it expects more security as compared to the postal voting system. The objective of the paper is twofold. Firstly, we proposed an efficient blind signature scheme using the identity-based cryptosystem in the random oracle model. The proposed scheme uses the combination of Boldyreva’s blind signature scheme and Choon-Cheon’s Identity-based signature. Additionally, we reduce its security to the Gap Diffie-Hellman Complexity (GDH). Under the adaptive chosen message and ID attacks it is secure against existential forgery attack. We show our proposed system performed better as compared to existing systems. Secondly, we construct an E-voting system based on our ID-based blind signature and Boneh’s short signature scheme (EVS-ID-BS) that fulfills the E-voting security requirements. To the best of our knowledge, EVS-ID-BS is the first practical implementation of E-voting system based on ID-BS Scheme which is constructed in the random oracle model. Proposed EVS-ID-BS scheme provides batch verifiability for a significantly large number of voters, needs less bandwidth cost and require less interaction with election authority.

On the unlinkability of randomization-enhanced Chaum’s blind signature scheme

Blind signature is a kind of digital signature with significant applications in anonymous electronic voting and electronic payment. In this paper, first, we analyze a recently introduced blind signature scheme and show that, without obtaining the signing key, the attacker can forge a valid signature for any arbitrary message. In other words, Dameri et al.'s blind signature scheme is universally forgeable. Then, we propose a new blind signature scheme based on the discrete logarithm problem. Finally, we introduce an elliptic curve-based variant of the proposed scheme which has lower computational overhead.

In this paper, we consider a scenario where a bitcoin liquidity provider sells bitcoins to clients. When a client pays for a bitcoin online, the provider is able to link the client's payment information to the bitcoin sold to that client. To address the privacy concerns of clients, we require that the bitcoin provider cannot tell the relationship between the real identities of clients and the sold bitcoins in the blockchain. This requirement can be effectively achieved by using blind signatures. However, existing blind signature schemes are incompatible with the Elliptic Curve Digital Signature Algorithm (ECDSA) which is used by most of the existing bitcoin protocol, thus cannot be applied directly in Bitcoin. In this paper, we propose a new blind signature scheme that allows generating a blind signature compatible with the standard ECDSA. Afterwards, we make use of the new scheme to achieve bitcoin transaction anonymity. The new scheme is built on a variant of the Paillier cryptosystem and its homomorphic properties. As long as the modified Paillier cryptosystem is semantically secure, the new blind signature scheme has blindness and unforgeability.

Voting is always considered as the most important hallmarks in the democratic society. However, there are plenty of problems of the traditional election such as inconvenience, non-mobility, unfairness, non-anonymity, and so on. Furthermore, the cost of the traditional voting often places a heavy burden on the nation. To solve the problems of the traditional election, the concept of “electronic voting” is proposed, where people are allowed to vote over the Internet. The properties of mobility and convenience are the most significant reasons why people may adopt the electronic voting mechanism in the future. In this article, we are going to present an efficient and flexible voting scheme which allows the voter having at most t out of n choices at the same time by employing Chaum’s blind signature scheme and the concept of an oblivious transfer protocol, where n is the number of candidates. Our proposed electronic voting scheme not only achieves lots of essential requirements of general electronic voting schemes but also possesses better efficiency than that of other related works.

In order to solve the problem of computational complexity brought by bilinear pairing in identity based blind signature, a new ID-based blind signature scheme is proposed combined with Elgamal algorithm, and the blind signature scheme is applied to the field of civil aviation data transmission firstly. The signer is not visible to the original message and can't restore the original message by the signed message. The use of hash function to deal with both private key and the identity information is secure under the Random Oracle Model. Based on the classical Elgamal algorithm, the problem belongs to the discrete logarithm problem. The scheme is applied to the field of civil aviation data transmission and the experimental results show that it can effectively resist key recovery attacks and signature forgery attacks. The scheme has strong anti-attack ability and effective operation ability. Compared with other schemes, it needs less module operation and exponential operation. To sum up, this scheme is better than other schemes in the civil aviation's field.

The rapid growing big data enforces many organizations to shift their data and services like digital right management, e-payment, and e-voting systems to the cloud. In such cloud-assisted services, the blind signature scheme could be one of the cryptographic tools, which provides the integrity of data and user anonymity. It allows the user to ask the signer for signing on message without disclosing any information about the content to the signer. Since several blind signature schemes have been proposed, but due to the expensive computation and bandwidth cost, they are impractical for the cloud-assisted as well as Internet-based environment. In this paper, we propose a new provable secure identity-based blind signature scheme with message recovery (IDBS-MR) using the elliptic curve cryptography. The proposed IDBS-MR scheme does not transmit the message with the signature while the message is recovered during verification round; hence it has the least message-signature length. The security analysis shows that the proposed IDBS-MR scheme is secured against existential forgery attack under the adaptive chosen message and ID attacks (EF-ID-CMA) under the assumption of solving the ECDL problem, and random oracle model (ROM) and achieves blindness property. The performance analysis shows that our scheme is efficient as compared to related existing schemes.

Blind signature allows a user to obtain a signature from an authority on any document, in such a way that the authority learns nothing about the message that is being signed. The blindness is an important property which distinguishes the blind signature from other signature schemes. Partially blind signature is an extension of blind signature that allows a signer to sign a partially blinded message that include pre-agreed information in the resulting signatures. Recently, Liao et al. proposed a pairing-based provable blind signature scheme without random oracles, and Hu et al. proposed an efficient ID-based partially blind signature scheme with security proof. But in this paper, we show that the two schemes do not satisfy the blindness and partially blindness, respectively. Liao et al.'s scheme is linkability and in Hu et al.'s scheme, a malicious user can replace pre-agreed common information with a special information

Blind signature is an interesting cryptographic primitive which allows user to get signature on his document from signatory authority, without leaking any information. Blind signature is useful in many e-commerce applications where user’s anonymity is the main concern. Since the Zhang et al., was the first to propose the identity based blind signature, many schemes based on bilinear pairing have been proposed. But the computational cost of pairing operation on elliptic curve is around 20 times the point multiplication on an elliptic curve. In order to save the running time, we present a new Identity-Based Blind Signature (ID-BS) scheme whose security is based on elliptic curve discrete logarithm problem (ECDLP). Performance comparison shows that proposed scheme reduces the cost of computation. Security analysis shows that proposed scheme is secure against the adversary and achieves the property of blindness and Non-forgeabillity. At the end; we propose an e-cash payment system based on our ID-based blind signature scheme.

Proxy blind signature which combines the properties of both proxy signature and blind signature. In a proxy blind signature scheme, the proxy signer is allowed to generate a blind signature on behalf of the original signer. The proxy blind signature scheme is useful in several applications such as e-voting, e-payment and mobile agent environments. In this paper, we present an efficient proxy blind signature scheme based on discrete logarithm problem, which satisfies the secure properties of both the blind signature scheme and the proxy signature scheme with low computation. Analysis shows that our scheme is secure and efficient.

We propose an efficient and provably secure threshold blind signature scheme based on Okamoto-Schnorr blind signature. In our scheme, any t (t < n) out of n signers can generate a blind signature and any one can verify the signature using the same verification process used in Okamoto-Schnorr blind signature. New scheme can be used for blind signature-based voting systems with multiple administrators and secure electronic cash systems to prevent their abuse. We prove that our scheme is to be as secure as Okamoto-Schnorr's blind signature scheme and more efficient than Juang et al.'s scheme [12].