1,346 research outputs found
SIGNCRYPTION ANALYZE
The aim of this paper is to provide an overview for the research that has been done so far in signcryption area. The paper also presents the extensions for the signcryption scheme and discusses the security in signcryption. The main contribution to this paper represents the implementation of the signcryption algorithm with the examples provided.ElGamal, elliptic curves, encryption, identity-based, proxy-signcryption, public key, ring-signcryption, RSA, signcryption
Signcryption schemes with threshold unsigncryption, and applications
The final publication is available at link.springer.comThe goal of a signcryption scheme is to achieve the same functionalities as encryption and signature together, but in a more efficient way than encrypting and signing separately. To increase security and reliability in some applications, the unsigncryption phase can be distributed among a group of users, through a (t, n)-threshold process. In this work we consider this task of threshold unsigncryption, which has received very few attention from the cryptographic literature up to now (maybe surprisingly, due to its potential applications). First we describe in detail the security requirements that a scheme for such a task should satisfy: existential unforgeability and indistinguishability, under insider chosen message/ciphertext attacks, in a multi-user setting. Then we show that generic constructions of signcryption schemes (by combining encryption and signature schemes) do not offer this level of security in the scenario of threshold unsigncryption. For this reason, we propose two new protocols for threshold unsigncryption, which we prove to be secure, one in the random oracle model and one in the standard model. The two proposed schemes enjoy an additional property that can be very useful. Namely, the unsigncryption protocol can be divided in two phases: a first one where the authenticity of the ciphertext is verified, maybe by a single party; and a second one where the ciphertext is decrypted by a subset of t receivers, without using the identity of the sender. As a consequence, the schemes can be used in applications requiring some level of anonymity, such as electronic auctions.Peer ReviewedPostprint (author's final draft
LPKI - A Lightweight Public Key Infrastructure for the Mobile Environments
The non-repudiation as an essential requirement of many applications can be
provided by the asymmetric key model. With the evolution of new applications
such as mobile commerce, it is essential to provide secure and efficient
solutions for the mobile environments. The traditional public key cryptography
involves huge computational costs and is not so suitable for the
resource-constrained platforms. The elliptic curve-based approaches as the
newer solutions require certain considerations that are not taken into account
in the traditional public key infrastructures. The main contribution of this
paper is to introduce a Lightweight Public Key Infrastructure (LPKI) for the
constrained platforms such as mobile phones. It takes advantages of elliptic
curve cryptography and signcryption to decrease the computational costs and
communication overheads, and adapting to the constraints. All the computational
costs of required validations can be eliminated from end-entities by
introduction of a validation authority to the introduced infrastructure and
delegating validations to such a component. LPKI is so suitable for mobile
environments and for applications such as mobile commerce where the security is
the great concern.Comment: 6 Pages, 6 Figure
Cryptanalysis of an Efficient Signcryption Scheme with Forward Secrecy Based on Elliptic Curve
The signcryption is a relatively new cryptographic technique that is supposed
to fulfill the functionalities of encryption and digital signature in a single
logical step. Several signcryption schemes are proposed throughout the years,
each of them having its own problems and limitations. In this paper, the
security of a recent signcryption scheme, i.e. Hwang et al.'s scheme is
analyzed, and it is proved that it involves several security flaws and
shortcomings. Several devastating attacks are also introduced to the mentioned
scheme whereby it fails all the desired and essential security attributes of a
signcryption scheme.Comment: 5 Pages, 2 Figure
An Elliptic Curve-based Signcryption Scheme with Forward Secrecy
An elliptic curve-based signcryption scheme is introduced in this paper that
effectively combines the functionalities of digital signature and encryption,
and decreases the computational costs and communication overheads in comparison
with the traditional signature-then-encryption schemes. It simultaneously
provides the attributes of message confidentiality, authentication, integrity,
unforgeability, non-repudiation, public verifiability, and forward secrecy of
message confidentiality. Since it is based on elliptic curves and can use any
fast and secure symmetric algorithm for encrypting messages, it has great
advantages to be used for security establishments in store-and-forward
applications and when dealing with resource-constrained devices.Comment: 13 Pages, 5 Figures, 2 Table
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