Multi-signcryption Scheme Research Articles

Extended identity based multi-signcryption scheme with public verifiability

Signcryption effectively accomplish encryption and signature procedure in a single logical step to acquire confidentiality, non-repudiation at minimum computational and communication overhead as compared to traditional scheme. In some applications, multiple senders authentic a message or document without revealing it by applying multiple signatures on it. It is not efficient to perform signcryption by each signer individually as unsigncryption cost is high. An alternative to reduce cost is multi signcryption. Numerous researchers worked on signcryption schemes to achieve security goals such as – confidentiality, non-repudiation, integrity, unforeability, forward secrecy and public verification. But none has provide solution to private key exposure. The biggest threat to the security is private key exposure and One time Pad (OTP) attack. With the increasing number of users, the threat is increasing on the low computation devices such as mobile phones, which requires private key for signature. Public key is derived from the identity of the user, if anyone comes to know corresponding private key can store the message and perform replay attack. In this paper we presented a scheme to reduce the threats caused by private key exposure, replay attack and OTP attack. According to us this is first ID based multi-signcryption with private key updation at a time period t.

Certificateless multi-signcryption scheme in standard model

A signcryption scheme can realise the security objectives of encryption and signature simultaneously, which has lower computational cost and communication overhead than the sign-then-encrypt approach. To adapt multi-user settings and solve key escrow problem of ID-based multi-signcryption schemes, we defined the formal model of certificateless multi-signcryption scheme and proposed a certificateless multi-signcryption scheme in the standard model. The scheme is proved secure against adaptive chosen ciphertext attacks and adaptive chosen message attacks under decisional bilinear Diffie-Hellman assumption and computational Diffie-Hellman assumption respectively.

Certificateless multi-signcryption scheme in standard model

Certificateless multi-signcryption scheme in standard model

An Efficient Identity based Multi-Proxy Multi-Signcryption Scheme from Bilinear Pairings

Signcryption is a cryptography primitive that fulfills both the functions of digital signature and encryption and guarantees non-repudiation, confidentiality and integrity in a more efficient way. In this paper, we propose an efficient and secure identity based multi-proxy multi signcryption scheme from bilinear pairings. In this scheme a group of proxy signcrypters could authorize by a group of original signcrypters. Then multi proxy multi signcryption could generate by the cooperation of all signcrypters in the proxy group.

Public Verifiable Identity based Multi-Proxy Multi-Signcryption Scheme from Bilinear Pairings

This paper presents public verifiable identity based multiproxy multisigncryption scheme from pairings. In this scheme a proxy signcrypter group could authorized as a proxy agent by the cooperation of all members in the original signcrypter group. Then the proxy signcryption can be generated by the cooperation of all the signcrypters in the authorized proxy signcrypter group on the behalf of the original signcrypter group. As compared to the scheme Liu and Xiao, the proposed scheme provides public verifiability of the signature along with simplified key management.

Certificateless Multi-Signcryption Scheme without Pairing

Certificateless public key cryptography is a new paradigm that simplifies the traditional PKC and solves the inherent key escrow problem suffered by ID-PKC. As realizing both encryption and signature security goals, certificateless signcryption is one of the most important security primitives in CL-PKC. To adapt multi-user settings, we present a certificateless multi-signcryption scheme without pairing. The performace analysis shows that the scheme is very efficient.

Efficient Identity Based Multi-Signcryption Scheme with Public Verifiability

Signcryption is a cryptographic primitive that provides the functionalities of digital signature and public key encryption simultaneously, at a lower computational costs and communication overheads than the traditional signature-then-encryption approach. In some applications, it is often required that multiple senders have to send a message in a secure and authenticated way. If signcryptions are performed individually by the group of senders, the cost involved in unsigncryption is high. So that it is not an efficient way to signcrypt the message separately. An efficient alternative method is multi-signcryption. In this paper, we propose an efficient identity based multi-signcryption scheme with public verifiability. This scheme provides the functionalities of both multi signatures and secure encryption for multiple senders; and these schemes enables to perform unsigncryption with the cost equal to a single unsigncryption irrespective of the number of senders. We discuss the security requirements such as confidentiality and unforgeability of the proposed scheme with the assumptions that the CBDH and CDH problems are intractable. Finally, we compare our scheme with the related schemes in terms of computational point of view.

Notes on a group-oriented setting’s multisigncryption scheme with threshold designcryption

Zhang et al. proposed recently a group-oriented multisigncryption scheme with threshold designcryption and affirmed that their scheme is secure under standard complexity assumptions. However, the note elaborates concrete attacks on its indistinguishability and unforgeability under their security models. We also provide the impossibility result of public ciphertext authenticity for the scheme.

Efficient and secure identity-based multi-signcryption scheme in standard model

Faced with the inefficiency problem of current identity-based multi-signcryption schemes,an efficient and secure identity-based multi-signcryption scheme was proposed.The new scheme eliminated the number of multiplicative operations,and increased the procedure of key verification.Furthermore,through security and efficiency analysis in the standard model,the new scheme is proved secure under computational Diffie-Hellman assumption and reduces the calculation work.Compared with the known schemes,the new scheme is more secure and efficient.

Analysis and Enhancement of Three Identity-based Signcryption Protocols

In 2006, Fagen LI et al. proposed an efficient identity-based signcryption scheme and declared that this scheme had the attributes of privacy, unforgeability, public verifiability, repudiation and forward security. After detailed analysis, we find that scheme does not meet the attributes which the author’s declared. Actually, an active attacker with the capacity of controlling the communication channel can replace the public key of the sender to forge a cipher text which can pass the unsigncrypt phase but don’t need to steal the private key of the sender. In 2009, Xiao LI et al. also found a method to forge a cipher text on the scheme of Fagen LI et al. Further, they proposed an improved identity-based signcryption scheme and declared their improved scheme had the attributes mentioned above. However we find a forged cipher text still can be constructed using the public key replacement attack. Finally, we point out the flaws in their schemes which our attack based on and proposed two corresponding enhanced schemes. In additional, we show that another Identity-Based Multi-Signcryption Scheme proposed by MENG Tao et al. in 2007 is insecure against the key replacement attack as well. In their scheme, an active attacker can replace the signcrypter’s public key and forge a valid cipher text to pass the examination of the receiver without the knowledge of the signcrypter’s private key. we discuss the flaws which lead to our attack succeeding to forge the valid cipher text and add the corresponding solution at last.

Identity-Based Multi-Signcryption with Public Verifiability

Multi-signcryption can meet the requirement of message signcryption with muti-participant. Since the existing identity-based multi-signcryption scheme cannot offer the function of public verifiability, based on identity and bilinear pairing on the Elliptic Curve, a new scheme with public verifiability is proposed. In the scheme, with the steps which is comparatively independent to the signcryption process, it can provide the public verification of each signcryption in need. Therefore, our scheme efficiently achieves the cryptographic functions of multi-signcryption.

Group-oriented setting’s multisigncryption scheme with threshold designcryption

Signcryption supports the authenticity and confidently in a single logic step and it has more efficient cost than the signature-then-encryption approach. Currently signcryption schemes only support a peer to peer secure message transfer between single users, and thus it cannot be adapted to the group users in multiple senders and receivers. In this paper, we propose a group-oriented multisigncryption scheme with threshold designcryption in multi-users setting, which combines the threshold secret sharing technology, zero knowledge proof for the bilinear map equality of two discrete logarithms, multi-signature and identity-based signcryption schemes. The ciphertext in the proposed scheme is computed by all the m members in sender group, and it can be decrypted only by t-out-of- n members in receiver group. We prove the security of the proposed scheme in several models including semantic security, unforgeability, public ciphertext authenticity and verifiability.

Identity-Based Multi-Signcryption Scheme without Random Oracles

Signcryption is a very important technology in message security and the sender's identity authentication for communication in the open channel.To adapt multi-user settings,this paper defines the formal model of identity-based multi-signcryption scheme and proposes the first identity-based multi-signcryption scheme without random oracles based on Waters' identity-based encryption scheme.The scheme is proved secure against adaptive chosen ciphertext attacks and adaptive chosen message attacks under decisional bilinear Diffie-Hellman assumption and computational Diffie-Hellman assumption respectively.

A Novel Identity-Based Multi-Signcryption Scheme

Message security and the sender's identity authentication for communication in the open channel is a basic and important technology of the internet. For keeping the message confidential and unforgeable, the sender can use a digital signature algorithm with his private key to sign the message, and then encrypts the signature on the message. Signcryption which was proposed by Zheng et. al in 1997 is a novel cryptographic primitive that simultaneously provides the authentication and encryption in a single logic step and at lower computational costs and communication overheads than the above sign-then-encrypt way. Since then, there are many signcryption schemes proposed. Only recently, a formal security proof model is formalized providing security proof for Zheng's signcryption in the random oracle model. In the ID-based cryptography, the complexity of the managing certificate is reduced. In this work, by combining a multisignature with an ID-based signcryption scheme, we build a security model of multi-signcryption to define confidentiality and unforgeability of the ID-based signcryption scheme and have proposed an ID-based multi-signcryption scheme based on the bilinear pairings to adapt to a multi-user setting. Given a message m, a receiver's identity IDB, and n sender's identities IDA1, IDA2, …, IDAn, for each sender Ai, it executes the followings steps: randomly pick xi ε Zq to compute Ri = xiP and ω = xiQIDB; send (Ri, ωi) to the other senders by a secure channel; (3)after receiving the other senders (Ri, ωi), Ai computes ω = e(Ppub, Σωj) to set c = H2(ω)⊕m and R = ΣRj; compute Si = xiH4(m) + H3(R,ω)SIDAi, where SIDAi is the private key of sender Ai. Then the resulting ciphertext is (c,S,R). To unsigcrypt the ciphertext (c,S,R) in the sender list L = (IDA1, IDA2, …, IDAn), the receiver with identity IDB can compute the following steps to recover and verify the message validity. compute ω = e(R,SIDB) and m = H2(ω)⊕c, where SIDB is private key of the receiver; accept the message if and only if the following equation holds [Formula: see text] By security analysis, we show that our scheme satisfies the two important properties of signcryption: confidentiality and unforgeability, and is proven to have been secure in the random oracle model. The security of the scheme is closely related to the Decisional Bilinear Diffie-Hellman assumption and the computational Diffie-Hellman assumption. Finally, by analyzing the efficiency of the scheme, we show that our scheme is very efficient, and only one pairing computation is needed in the signcryption phase, three pairing operators are needed in the unsigncrytion phase, and the ciphertext size is about 420 bits.

A novel identity-based multi-signcryption scheme

Signcryption is a novel cryptographic primitive that simultaneously provides the authentication and encryption in a single logic step. In this work, by combining multi-signature with ID-based signcryption scheme, we build security model of multi-signcryption and have proposed an ID-based multi-signcryption scheme based on the bilinear pairings to adapt to multi-user setting. Then we prove that our proposed scheme was secure and satisfies the confidentiality and unforgeability. And the fixed verification computational cost is needed in our proposed signcryption, thus, it is efficient.