Certificateless ring signature based on RSA problem and DL problem

Certificateless public key cryptography solves the certificate management problem in the traditional public key cryptography and the key escrow problem in identity-based cryptography. RSA is a key cryptography technique and provides various interfaces for the applied software in real-life scenarios. To the best of our knowledge, all of the known certificateless ring signature schemes employed bilinear pairings. But the computation cost of the pairings is much higher than that of the exponentiation in a RSA group. In this paper, we present the first certificateless ring signature scheme without pairing and prove the security in the random oracle model. The security of the scheme is closely related to the RSA problem and the discrete logarithm (DL) problem

Insecurity of a provably secure and lightweight certificateless signature scheme for IIoT environments

Recently, Karati et al. presented a lightweight certificateless signature scheme for industrial Internet of Things (IIoT) environments, and claimed the scheme was provably secure in the standard model. In this paper, it is indicated that the scheme is not secure by showing two concrete attacks

Certificateless Proxy Signature from RSA

Although some good results were achieved in speeding up the computation of pairing function in recent years, it is still interesting to design efficient cryptosystems with less bilinear pairing operation. A proxy signature scheme allows a proxy signer to sign messages on behalf of an original signer within a given context. We propose a certificateless proxy signature (CLPS) scheme from RSA and prove its security under the strongest security model where the Type I/II adversary is a super Type I/II adversary

Public-Key Cryptography Based on Tropical Circular Matrices

Some public-key cryptosystems based on the tropical semiring have been proposed in recent years because of their increased efficiency, since the multiplication is actually an ordinary addition of numbers and there is no ordinary multiplication of numbers in the tropical semiring. However, most of these tropical cryptosystems have security defects because they adopt a public matrix to construct commutative semirings. This paper proposes new public-key cryptosystems based on tropical circular matrices. The security of the cryptosystems relies on the NP-hard problem of solving tropical nonlinear systems of integers. Since the used commutative semiring of circular matrices cannot be expressed by a known matrix, the cryptosystems can resist KU attacks. There is no tropical matrix addition operation in the cryptosystem, and it can resist RM attacks. The new cryptosystems can be considered as a potential post-quantum cryptosystem

Certificateless Proxy Signature from RSA

Although some good results were achieved in speeding up the computation of pairing function in recent years, it is still interesting to design efficient cryptosystems with less bilinear pairing operation. A proxy signature scheme allows a proxy signer to sign messages on behalf of an original signer within a given context. We propose a certificateless proxy signature (CLPS) scheme from RSA and prove its security under the strongest security model where the Type I/II adversary is a super Type I/II adversary

Public-Key Cryptography Based on Tropical Circular Matrices

Some public-key cryptosystems based on the tropical semiring have been proposed in recent years because of their increased efficiency, since the multiplication is actually an ordinary addition of numbers and there is no ordinary multiplication of numbers in the tropical semiring. However, most of these tropical cryptosystems have security defects because they adopt a public matrix to construct commutative semirings. This paper proposes new public-key cryptosystems based on tropical circular matrices. The security of the cryptosystems relies on the NP-hard problem of solving tropical nonlinear systems of integers. Since the used commutative semiring of circular matrices cannot be expressed by a known matrix, the cryptosystems can resist KU attacks. There is no tropical matrix addition operation in the cryptosystem, and it can resist RM attacks. The new cryptosystems can be considered as a potential post-quantum cryptosystem

An efficient certificateless multi-receiver threshold decryption scheme

Threshold decryption allows only quorum cooperate users to decrypt ciphertext encrypted under a public key. However, such threshold decryption scheme cannot be applied well in this situation where all users have their public and private key pairs, but do not share any private keys corresponding to the public keys, such as mobile network featured with dynamic character. The direct way to achieve threshold decryption in this case is to divide the message into several pieces and then encrypt these pieces with the public keys of different users. However, this is very inefficient. Multireceiver threshold decryption scheme that could be applied efficiently in the above situation. Recently, some certificateless (ID-based) multireceiver threshold decryption (signcryption) schemes are introduced. But the bilinear pairings are used in most of the existing schemes. In this paper, we propose an efficient certificateless threshold decryption scheme using elliptic curve cryptography (ECC) without bilinear pairing. Performance analysis shows that the proposed scheme has lower computation cost than existing some threshold decryption schemes in both encryption and decryption process. Security analysis shows that our scheme is IND-CCA secure, and no one outside of selected receivers can disclose receivers identities, against the adversaries defined in CL-PKC system under the random oracle model

Two new identity-based threshold ring signature schemes

Dr Research Foundation of Guizhou Normal University of Guizhou Province, P.R. China; Science and Technology Foundation of Guizhou Province, P.R. China [LKS[2013]02]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. (C) 2014 Elsevier B.V. All rights reserved

Certificateless Proxy Signature from RSA

National Natural Science Foundation of China [11261060]; Dr. Research Foundation of Guizhou Normal University of Guizhou Province, China; Science and Technology Foundation of Guizhou Province, China [LKS[2013]02]Although some good results were achieved in speeding up the computation of pairing function in recent years, it is still interesting to design efficient cryptosystems with less bilinear pairing operation. A proxy signature scheme allows a proxy signer to sign messages on behalf of an original signer within a given context. We propose a certificateless proxy signature (CLPS) scheme from RSA and prove its security under the strongest security model where the Type I/II adversary is a super Type I/II adversary