83 research outputs found
Still Wrong Use of Pairings in Cryptography
Several pairing-based cryptographic protocols are recently proposed with a
wide variety of new novel applications including the ones in emerging
technologies like cloud computing, internet of things (IoT), e-health systems
and wearable technologies. There have been however a wide range of incorrect
use of these primitives. The paper of Galbraith, Paterson, and Smart (2006)
pointed out most of the issues related to the incorrect use of pairing-based
cryptography. However, we noticed that some recently proposed applications
still do not use these primitives correctly. This leads to unrealizable,
insecure or too inefficient designs of pairing-based protocols. We observed
that one reason is not being aware of the recent advancements on solving the
discrete logarithm problems in some groups. The main purpose of this article is
to give an understandable, informative, and the most up-to-date criteria for
the correct use of pairing-based cryptography. We thereby deliberately avoid
most of the technical details and rather give special emphasis on the
importance of the correct use of bilinear maps by realizing secure
cryptographic protocols. We list a collection of some recent papers having
wrong security assumptions or realizability/efficiency issues. Finally, we give
a compact and an up-to-date recipe of the correct use of pairings.Comment: 25 page
Weaknesses of the Boyd-Mao Deniable Authenticated key Establishment for Internet Protocols
In 2003, Boyd and Mao proposed two deniable authenticated key establishment
protocols using elliptic curve pairings for Internet protocols, one is based on
Diffie-Hellman key exchange and the other is based on Public-Key Encryption
approach. For the use of elliptic curve pairings, they declared that their schemes could
be more efficient than the existing Internet Key Exchange (IKE), nowadays. However
in this paper, we will show that both of Boyd-Mao¥Šs protocols suffer from the
key-Compromise Impersonation attack
Deniable Key Establishment Resistance against eKCI Attacks
In extended Key Compromise Impersonation (eKCI) attack against authenticated key establishment (AKE) protocols the adversary impersonates one party, having the long term key and the ephemeral key of the other peer party. Such an attack can be mounted against variety of AKE protocols, including 3-pass HMQV. An intuitive countermeasure, based on BLS (BonehâLynnâShacham) signatures, for strengthening HMQV was proposed in literature. The original HMQV protocol fulfills the deniability property: a party can deny its participation in the protocol execution, as the peer party can create a fake protocol transcript indistinguishable from the real one. Unfortunately, the modified BLS based version of HMQV is not deniable. In this paper we propose a method for converting HMQV (and similar AKE protocols) into a protocol resistant to eKCI attacks but without losing the original deniability property. For that purpose, instead of the undeniable BLS, we use a modification of Schnorr authentication protocol, which is deniable and immune to ephemeral key leakages
The Cryptographic Security of the German Electronic Identity Card
In November 2010, the German government started to issue the new electronic identity card (eID) to its citizens. Besides its original utilization as a âvisualâ identification document, the eID card can be used by the cardholder to prove oneâs identity at border control and to enhance security of authentication processes over the Internet, with the eID card serving as a token to reliably
transmit personal data to service providers or terminals, respectively. To this end, the German Federal Office for Information Security (BSI) proposed several cryptographic protocols now deployed on the eID card.
The Password Authenticated Connection Establishment (PACE) protocol secures the wireless communication between the eID card and the userâs local card reader, based on a cryptographically weak password like the PIN chosen by the card owner. Subsequently, the Extended Access Control (EAC) protocol is executed by the chip and the service provider to mutually authenticate and agree on a shared secret session key. This key is then used in the secure channel protocol, called Secure Messaging (SM). Finally, an optional protocol,
called Restricted Identification (RI), provides a method to use pseudonyms such that they can be linked by individual service providers, but not across different service providers (even not by malicious ones).
This thesis consists of two parts. First, we present the above protocols and provide a rigorous analysis on their security from a cryptographic point of view. We show that the Germen eID card provides reasonable security for authentication and exchange of sensitive information allaying concerns regarding its usage.
In the second part of this thesis, we introduce two possible modifications to enhance the security of these protocols even further. Namely, we show how to (a) add to PACE an additional efficient chip authentication step, and (b) augment RI to allow also for signatures under pseudonyms
Authentication schemes for Smart Mobile Devices: Threat Models, Countermeasures, and Open Research Issues
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.This paper presents a comprehensive investigation of authentication schemes for smart mobile devices. We start by providing an overview of existing survey articles published in the recent years that deal with security for mobile devices. Then, we give a classification of threat models in smart mobile devices in five categories, including, identity-based attacks, eavesdropping-based attacks, combined eavesdropping and identity-based attacks, manipulation-based attacks, and service-based attacks. This is followed by a description of multiple existing threat models. We also provide a classification of countermeasures into four types of categories, including, cryptographic functions, personal identification, classification algorithms, and channel characteristics. According to the characteristics of the countermeasure along with the authentication model iteself, we categorize the authentication schemes for smart mobile devices in four categories, namely, 1) biometric-based authentication schemes, 2) channel-based authentication schemes, 3) factors-based authentication schemes, and 4) ID-based authentication schemes. In addition, we provide a taxonomy and comparison of authentication schemes for smart mobile devices in form of tables. Finally, we identify open challenges and future research directions
Secure Chaotic Maps-based Group Key Agreement Scheme with Privacy Preserving
Abstract Nowadays chaos theory related to cryptography has been addressed widely, so there is an intuitive connection between group key agreement and chaotic maps. Such a connector may lead to a novel way to construct authenticated and efficient group key agreement protocols. Many chaotic maps based two-party/three-party password authenticated key agreement (2PAKA/3PAKA) schemes have been proposed. However, to the best of our knowledge, no chaotic maps based group (N-party) key agreement protocol without using a timestamp and password has been proposed yet. In this paper, we propose the first chaotic maps-based group authentication key agreement protocol. The proposed protocol is based on chaotic maps to create a kind of signcryption method to transmit authenticated information and make the calculated consumption and communicating round restrict to an acceptable bound. At the same time our proposed protocol can achieve members' revocation or join easily, which not only refrains from consuming modular exponential computing and scalar multiplication on an elliptic curve, but is also robust to resist various attacks and achieves perfect forward secrecy with privacy preserving
Isogeny-based Quantum-resistant Undeniable Blind Signature Scheme
In this paper, we propose an Undeniable Blind Signature scheme (UBSS) based on isogenies between supersingular elliptic curves. The proposed UBSS is an extension of the Jao-Soukharev undeniable signature scheme. We formalize the notion of a UBSS by giving the formal definition. We then study its properties along with the pros and cons. Based on this, we provide a couple of its applcations. We then state the isogeny problems in a more general form and discuss their computational hardnesses. Finally, we prove that the proposed scheme is secure in the presence of a quantum adversary under certain assumptions
Security Analysis of ECC Based Protocols
Elliptic curve cryptography (ECC) is extensively used in various multifactor authentication protocols. In this work, various recent ECC based authentication and key exchange protocols are subjected to threat modeling and static analysis to detect vulnerabilities, and to enhance them to be more secure against threats. This work demonstrates how currently used ECC based protocols are vulnerable to attacks. If protocols are vulnerable, damages could include critical data loss and elevated privacy concerns. The protocols considered in thiswork differ in their usage of security factors (e.g. passwords, pins, and biometrics), encryption and timestamps. The threatmodel considers various kinds of attacks including denial of service, man in the middle, weak authentication and SQL injection. Countermeasures to reduce or prevent such attacks are suggested. Beyond cryptanalysis of current schemes and proposal of new schemes, the proposed adversary model and criteria set forth provide a benchmark for the systematic evaluation of future two-factor authentication proposals
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