International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Mark Manulis

Publications

Year
Venue
Title
2014
EPRINT
2014
EPRINT
2014
EPRINT
2011
ASIACRYPT
2010
PKC
2008
EPRINT
Universally Composable Security Analysis of TLS---Secure Sessions with Handshake and Record Layer Protocols
We present a security analysis of the complete TLS protocol in the Universal Composable security framework. This analysis evaluates the composition of key exchange functionalities realized by the TLS handshake with the message transmission of the TLS record layer to emulate secure communication sessions and is based on the adaption of the secure channel model from Canetti and Krawczyk to the setting where peer identities are not necessarily known prior the protocol invocation and may remain undisclosed. Our analysis shows that TLS, including the Diffie-Hellman and key transport suites in the uni-directional and bi-directional models of authentication, securely emulates secure communication sessions.
2008
EPRINT
Authenticated Wireless Roaming via Tunnels: Making Mobile Guests Feel at Home
In wireless roaming a mobile device obtains a service from some foreign network while being registered for the similar service at its own home network. However, recent proposals try to keep the service provider role behind the home network and let the foreign network create a tunnel connection through which all service requests of the mobile device are sent to and answered directly by the home network. Such Wireless Roaming via Tunnels (WRT) offers several (security) benefits but states also new security challenges on authentication and key establishment, as the goal is not only to protect the end-to-end communication between the tunnel peers but also the tunnel itself. In this paper we formally specify mutual authentication and key establishment goals for WRT and propose an efficient and provably secure protocol that can be used to secure such roaming session. Additionally, we describe some modular protocol extensions to address resistance against DoS attacks, anonymity of the mobile device and unlinkability of its roaming sessions, as well as the accounting claims of the foreign network in commercial scenarios.
2007
EPRINT
Provably Secure Framework for Information Aggregation is Sensor Networks
Mark Manulis Jörg Schwenk
Information aggregation is an important operation in wireless sensor networks executed for the purpose of monitoring and reporting of the environmental data. Due to the performance constraints of sensor nodes the in-network form of the aggregation is especially attractive since it allows to save expensive resources during the frequent network queries. Easy accessibility of networks and nodes and almost no physical protection against corruptions arise high challenges on the security of the aggregation process. Especially, protection against attacks aiming to falsify the aggregated result is considered to be of prime importance. In this paper we propose a novel security model for the aggregation process based on the well-established cryptographic techniques, focusing on the scenario with the single aggregator node. In order to show soundness and feasibility of our definitions we describe a generic practical approach that achieves security against node corruptions during the aggregation process in a provable cryptographic way based solely on the symmetric cryptographic primitives. To the best of our knowledge this is the first paper which aims to combine the paradigm of provable security in the cryptographic sense with the task of information aggregation in WSNs.
2006
EPRINT
Survey on Security Requirements and Models for Group Key Exchange
Mark Manulis
In this report we provide an analytical survey on security issues that are relevant for group key exchange (GKE) protocols. We start with the description of the security requirements that have been informally described in the literature and widely used to analyze security of earlier GKE protocols. Most of these definitions were originally stated for two-party protocols and then adapted to a group setting. These informal definitions are foundational for the later appeared formal security models for GKE protocols whose development, strengths, and weaknesses are also described and analyzed.
2006
EPRINT
Linkable Democratic Group Signatures
In a variety of group-oriented applications cryptographic primitives like group signatures or ring signatures are valuable methods to achieve anonymity of group members. However, in their classical form, these schemes cannot be deployed for applications that simultaneously require (i) to avoid centralized management authority like group manager and (ii) the signer to be anonymous only against non-members while group members have rights to trace and identify the signer. The idea of recently introduced {\it democratic group signatures} is to provide these properties. Based on this idea we introduce a group-oriented signature scheme that allows the group members to trace the identity of any other group member who issued a signature while non-members are only able to link the signatures issued by the same signer without tracing. For this purpose the signature scheme assigns to every group member a unique pseudonym that can be used by any non-member verifier to communicate with the anonymous signer from the group. We present several group-oriented application scenarios where this kind of linkability is essential. We propose a concrete linkable democratic group signature scheme for two-parties, prove its security in the random oracle model, and describe how to modularly extend it to the multi-party case.
2006
EPRINT
On Security Models and Compilers for Group Key Exchange Protocols
Group key exchange (GKE) protocols can be used to guarantee confidentiality and group authentication in a variety of group applications. The notion of provable security subsumes the existence of an abstract formalization (security model) that considers the environment of the protocol and identifies its security goals. The first security model for GKE protocols was proposed by Bresson, Chevassut, Pointcheval, and Quisquater in 2001, and has been subsequently applied in many security proofs. Their definitions of AKE- and MA-security became meanwhile standard. In this paper we analyze the BCPQ model and some of its later appeared modifications and identify several security risks resulting from the technical construction of this model – the notion of partnering. Consequently, we propose a revised model with extended definitions for AKE- and MA-security capturing, in addition, attacks of malicious protocol participants. Further, we analyze some well-known generic solutions (compilers) for AKE- and MA-security of GKE protocols proposed based on the definitions of the BCPQ model and its variants and identify several limitations resulting from the underlying assumptions. In order to remove these limitations and at the same time to show that our revised security model is in fact practical enough for the construction of reductionist security proofs we describe a modified compiler which provides AKE- and MA-security for any GKE protocol, under standard cryptographic assumptions.
2006
EPRINT
Security-Focused Survey on Group Key Exchange Protocols
Mark Manulis
In this paper we overview a large number of currently known group key exchange protocols while focusing on the protocols designed for more than three participants (for an overview of two- and three-party key exchange protocols we refer to [BM03, DB05c]). For each mentioned protocol we briefly describe the current state of security based on the original analysis as well as later results appeared in the literature. We distinguish between (i) protocols with heuristic security arguments based on informally defined security requirements and (ii) protocols that have been proven secure in one of the existing security models for group key exchange. Note, this paper continues the work started in Manulis (ePrint Rep. 2006/388) which provides an analytical survey on security requirements and currently known models for group key exchange. We emphasize that the following survey focuses on the security aspects of the protocols and does not aim to provide any efficiency comparison. The reader interested in this kind of surveys we refer to Rafaeli and Hutchison (ACM Comp. Surveys, 2003) and Amir et al. (ACM Trans. on Inf. and Syst. Sec., 2004).
2005
EPRINT
Democratic Group Signatures on Example of Joint Ventures
Mark Manulis
In the presence of economic globalization joint venture is one of the most common and effective means of conducting business internationally. By building joint ventures companies form strategic alliances that help them to enter new economic markets and further their business goals in a cooperative effort without loosing own independence. Upon building a joint venture company, two or more "parent" companies agree to share capital, technology, human ressources, risks and rewards in a formation of a new entity under shared control by a "board of directors", which consists of representatives of "parent" companies. The establishment of such shared control is tricky and relies generally on the "trust, but verify" relationship, i.e., companies trust the information they receive from prospective partners, but it is a good business practice to verify the facts. In this paper we focus on the issue of the shared financial control in a joint venture. We consider the mostly preferred form of the control where every member of the board is able to issue payment orders on behalf of the joint venture, but at the same time representatives of other companies, should be able to monitor the accounting to achieve fairness in the spending of shared funds. For this form of the shared control we propose a new secure group-oriented signature scheme, called a {\it democratic group signature} scheme, which results from the modification of the standard notion of group signatures by eliminating the role of the group manager. We also show that existing schemes, e.g., ring and group signatures, cannot be used to realize the required shared control based on the "trust, but verify" relationship.

Program Committees

PKC 2014
PKC 2010