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

An ICMetrics Based Lightweight Security Architecture Using Lattice Signcryption

The advent of embedded systems has completely transformed the information landscape. With the explosive growth in the use of interactive real-time technologies, this internet landscape aims to support an even broader range of application domains. The large amount of data that is exchanged by these applications has made them an attractive target for attacks. Thus it is important to employ security mechanisms to protect these systems from attackers. A major challenge facing researchers is the resource constrained nature of these systems, which renders most of the traditional security mechanisms almost useless. In this paper we propose a lightweight ICmetrics based security architecture using lattices. The features of the proposed architecture fulfill both the requirements of security as well as energy efficiency. The proposed architecture provides authentication, confidentiality, non-repudiation and integrity of data. Using the identity information derived from ICmetrics of the device, we further construct a sign cryption scheme based on lattices that makes use of certificate less PKC to achieve the security requirements of the design. This scheme is targeted on resource constrained environments, and can be used widely in applications that require sufficient levels of security with limited resources

Lightweight certificateless and provably-secure signcryptosystem for the internet of things

International audienceIn this paper, we propose an elliptic curve-based signcryption scheme derived from the standardized signature KCDSA (Korean Certificate-based Digital Signature Algorithm) in the context of the Internet of Things. Our solution has several advantages. First, the scheme is provably secure in the random oracle model. Second, it provides the following security properties: outsider/insider confidentiality and unforgeability; non-repudiation and public verifiability, while being efficient in terms of communication and computation costs. Third, the scheme offers the certificateless feature, so certificates are not needed to verify the user's public keys. For illustration, we conducted experimental evaluation based on a sensor Wismote platform and compared the performance of the proposed scheme to concurrent scheme

An Efficient Online/Offline Signcryption Scheme for Internet of Things in Smart Home

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Signcryption with Proxy Re-encryption

Confidentiality and authenticity are two of the most fundamental problems in cryptography. Many applications require both confidentiality and authenticity, and hence an efficient way to get both together was very desirable. In 1997, Zheng proposed the notion of ``signcryption\u27\u27, a single primitive which provides both confidentiality and authenticity in a way that\u27s more efficient than signing and encrypting separately. Proxy re-encryption is a primitive that allows a semi-trusted entity called the ``proxy\u27\u27 to convert ciphertexts addressed to a ``delegator\u27\u27 to those that can be decrypted by a ``delegatee\u27\u27, by using some special information given by the delegator, called the ``rekey\u27\u27. In this work, we propose the notion of signcryption with proxy re-encryption (SCPRE), and motivate the same. We define security models for SCPRE, and also propose a concrete unidirectional, non-interactive identity-based SCPRE construction. We also provide complete proofs of security for the scheme in the security models defined. We finally provide directions for further research in this area

On the Connection between Signcryption and One-pass Key Establishment

Key establishment between two parties that uses only one message transmission is referred to as one-pass key establishment (OPKE). OPKE provides the opportunity for very efficient constructions, even though they will typically provide a lower level of security than the corresponding multi-pass variants. In this paper, we explore the intuitive connection between signcryption and OPKE. By establishing a formal relationship between these two primitives, we show that with appropriate security notions, OPKE can be used as a signcryption KEM and vice versa. In order to establish the connection we explore the definitions of security for signcryption (KEM) and give new and generalised definitions. By making our generic constructions concrete we are able to provide new examples of signcryption KEMs and an OPKE protocol

Fast and Proven Secure Blind Identity-Based Signcryption from Pairings

We present the first blind identity-based signcryption (BIBSC). We formulate its security model and define the security notions of blindness and parallel one-more unforgeability (p1m-uf). We present an efficient construction from pairings, then prove a security theorem that reduces its p1m-uf to Schnorr¡¦s ROS Problem in the random oracle model plus the generic group and pairing model. The latter model is an extension of the generic group model to add support for pairings, which we introduce in this paper. In the process, we also introduce a new security model for (non-blind) identity-based signcryption (IBSC) which is a strengthening of Boyen¡¦s. We construct the first IBSC scheme proven secure in the strenghened model which is also the fastest (resp. shortest) IBSC in this model or Boyen¡¦s model. The shortcomings of several existing IBSC schemes in the strenghened model are shown

Security Analysis of Two Signcryption Schemes

Abstract. Signcryption is a new cryptographic primitive that performs signing and encryption simultaneously, at a cost significantly lower than that required by the traditional signature-then-encryption approach. In this paper, we present a security analysis of two such schemes: the Huang-Chang convertible signcryption scheme [12], and the Kwak-Moon group signcryption scheme [13]. Our results show that both schemes are insecure. Specifically, the Huang-Chang scheme fails to provide confidentiality, while the Kwak-Moon scheme does not satisfy the properties of unforgeability, coalition-resistance, and traceability

On the joint security of signature and encryption schemes under randomness reuse: efficiency and security amplification

Lecture Notes in Computer Science, 7341We extend the work of Bellare, Boldyreva and Staddon on the systematic analysis of randomness reuse to construct multi-recipient encryption schemes to the case where randomness is reused across different cryptographic primitives. We find that through the additional binding introduced through randomness reuse, one can actually obtain a security amplification with respect to the standard black-box compositions, and achieve a stronger level of security. We introduce stronger notions of security for encryption and signatures, where challenge messages can depend in a restricted way on the random coins used in encryption, and show that two variants of the KEM/DEM paradigm give rise to encryption schemes that meet this enhanced notion of security. We obtain the most efficient signcryption scheme to date that is secure against insider attackers without random oracles.(undefined