A New Security Model for Cross-Realm C2C-PAKE Protocol

Cross realm client-to-client password authenticated key exchange (C2C-PAKE) schemes are designed to enable two clients in different realms to agree on a common session key using different passwords. In 2006, Yin-Bao presented the first provably secure cross-realm C2C-PAKE, which security is proven rigorously within a formally defined security model and based on the hardness of some computationally intractable assumptions. However, soon after, Phan et al. pointed out that the Yin-Bao scheme was flawed. In this paper, we first analyze the necessary security attributes in the cross-realm C2C-PAKE scenario, and then a new security model for cross-realm C2C-PAKE is given. Analogous to the general construction of 3PAKE protocol for single server C2C-PAKE setting, we give a general construction of cross-realm C2C-PAKE protocol, which security is proved in the new security model

Efficient and Secure Cross-Realm Client-to-Client Password-Authenticated Key Exchange

[[conferencetype]]國際[[conferencedate]]20120326~20120329[[iscallforpapers]]Y[[conferencelocation]]Fukuoka, Japa

Security of two recent constant-round password authenticated group key exchange schemes

When humans interact with machines in their daily networks, it is important that security of the communications is offered, and where the involved shared secrets used to achieve this are easily remembered by humans. Password-based authenticated group key exchange (PAGKE) schemes allow group users to share a session key based on a human-memorizable password. In this paper, we consider two PAGKE schemes that build on the seminal scheme of Burmester and Desmedt. Weshow an undetectable online dictionary attack on the first scheme, and exploit the partnering definition to break the key indistinguishability of the second scheme

Analysis of Two Pairing-Based Three-Party Password Authenticated Key Exchange Protocols

Password-Authenticated Key Exchange (PAKE) protocols allow parties to share secret keys in an authentic manner based on an easily memorizable password. Recently, Nam et al. showed that a provably secure three-party password-based authenticated key exchange protocol using Weil pairing by Wen et al. is vulnerable to a man-in-the-middle attack. In doing so, Nam et al. showed the flaws in the proof of Wen et al. and described how to fix the problem so that their attack no longer works. In this paper, we show that both Wen et al. and Nam et al. variants fall to key compromise impersonation by any adversary. Our results underline the fact that although the provable security approach is necessary to designing PAKEs, gaps still exist between what can be proven and what are really secure in practice

Security of Group Key Exchange Protocols with Different Passwords

Password-based authenticated group key exchange protocols allow group users to jointly share a session key based on a human-memorizable password. In this paper, we present an undetectable online dictionary attack on N-EKE-D, a recent provably secure protocol designed to explicitly resist this type of attack. Thus, our result contradicts the design goal. We also give a simple attack on the key indistinguishability of N-EKE-D and two N-EKE-M variants that exploits the definition of partnering in their security model

Cryptanalysis of a new ultralightweight RFID authentication protocol—SASI

Since RFID tags are ubiquitous and at times even oblivious to the human user, all modern RFID protocols are designed to resist tracking so that the location privacy of the human RFID user is not violated. Another design criterion for RFIDs is the low computational effort required for tags, in view that most tags are passive devices that derive power from an RFID reader’s signals. Along this vein, a class of ultralightweight RFID authentication protocols has been designed, which uses only the most basic bitwise and arithmetic operations like exclusive- OR, OR, addition, rotation, and so forth. In this paper, we analyze the security of the SASI protocol, a recently proposed ultralightweight RFID protocol with better claimed security than earlier protocols. We show that SASI does not achieve resistance to tracking, which is one of its design objectives

A New Security Model for Cross-Realm C2C-PAKE Protocol ∗

Abstract. Cross realm client-to-client password authenticated key exchange (C2C-PAKE) schemes are designed to enable two clients in different realms to agree on a common session key using different passwords. In 2006, Yin-Bao presented the first provably secure cross-realm C2C-PAKE, which security is proven rigorously within a formally defined security model and based on the hardness of some computationally intractable assumptions. However, soon after, Phan et al. pointed out that the Yin-Bao scheme was flawed. In this paper, we first analyze the necessary security attributes in the cross-realm C2C-PAKE scenario, and then a new security model for cross-realm C2C-PAKE is given. Analogous to the general construction of 3PAKE protocol for single server C2C-PAKE setting, we give a general construction of cross-realm C2C-PAKE protocol, which security is proved in the new security model. Key word: Password-authenticated key exchange, cross realm, client-to-client, provably secure, security model.

Framework for privacy-aware content distribution in peer-to- peer networks with copyright protection

The use of peer-to-peer (P2P) networks for multimedia distribution has spread out globally in recent years. This mass popularity is primarily driven by the efficient distribution of content, also giving rise to piracy and copyright infringement as well as privacy concerns. An end user (buyer) of a P2P content distribution system does not want to reveal his/her identity during a transaction with a content owner (merchant), whereas the merchant does not want the buyer to further redistribute the content illegally. Therefore, there is a strong need for content distribution mechanisms over P2P networks that do not pose security and privacy threats to copyright holders and end users, respectively. However, the current systems being developed to provide copyright and privacy protection to merchants and end users employ cryptographic mechanisms, which incur high computational and communication costs, making these systems impractical for the distribution of big files, such as music albums or movies.El uso de soluciones de igual a igual (peer-to-peer, P2P) para la distribución multimedia se ha extendido mundialmente en los últimos años. La amplia popularidad de este paradigma se debe, principalmente, a la distribución eficiente de los contenidos, pero también da lugar a la piratería, a la violación del copyright y a problemas de privacidad. Un usuario final (comprador) de un sistema de distribución de contenidos P2P no quiere revelar su identidad durante una transacción con un propietario de contenidos (comerciante), mientras que el comerciante no quiere que el comprador pueda redistribuir ilegalmente el contenido más adelante. Por lo tanto, existe una fuerte necesidad de mecanismos de distribución de contenidos por medio de redes P2P que no supongan un riesgo de seguridad y privacidad a los titulares de derechos y los usuarios finales, respectivamente. Sin embargo, los sistemas actuales que se desarrollan con el propósito de proteger el copyright y la privacidad de los comerciantes y los usuarios finales emplean mecanismos de cifrado que implican unas cargas computacionales y de comunicaciones muy elevadas que convierten a estos sistemas en poco prácticos para distribuir archivos de gran tamaño, tales como álbumes de música o películas.L'ús de solucions d'igual a igual (peer-to-peer, P2P) per a la distribució multimèdia s'ha estès mundialment els darrers anys. L'àmplia popularitat d'aquest paradigma es deu, principalment, a la distribució eficient dels continguts, però també dóna lloc a la pirateria, a la violació del copyright i a problemes de privadesa. Un usuari final (comprador) d'un sistema de distribució de continguts P2P no vol revelar la seva identitat durant una transacció amb un propietari de continguts (comerciant), mentre que el comerciant no vol que el comprador pugui redistribuir il·legalment el contingut més endavant. Per tant, hi ha una gran necessitat de mecanismes de distribució de continguts per mitjà de xarxes P2P que no comportin un risc de seguretat i privadesa als titulars de drets i els usuaris finals, respectivament. Tanmateix, els sistemes actuals que es desenvolupen amb el propòsit de protegir el copyright i la privadesa dels comerciants i els usuaris finals fan servir mecanismes d'encriptació que impliquen unes càrregues computacionals i de comunicacions molt elevades que fan aquests sistemes poc pràctics per a distribuir arxius de grans dimensions, com ara àlbums de música o pel·lícules

Evaluation of the new Design Summer Year weather data using parametrical buildings

The Charted Institution of Building Services Engineers (CIBSE) updated the near extreme weather (Design Summer Year – DSY) for all 14 locations in the UK in 2016. This new release attempts to address the underlying shortcomings of the previous definition where the averaged dry bulb temperature was the sole metric to choose DSY among source weather years. The aim of this research is to evaluate whether the new definition of the probabilistic DSYs can consistently represent near extreme condition. London historical weather data and their correspondent DSYs were used in this research. Dynamic thermal modelling using EnergyPlus was carried out on large number single zone offices (parametric study) which represent a large portion of cellular offices in the UK. The predicted indoor warmth from the sample building models show that these new definitions are not always able to represent near extreme conditions. Using multiple years as DSY is able to capture different types of summer warmth but how to use one or all of these DSYs to make informed judgement on overheating is rather challenging. The recommended practice from this research is to use more warm years for the evaluation of overheating and choose the near extreme weather from the predicted indoor warmt