Global navigation satellite systems (GNSS) like GPS but also Galileo, GLONASS, and Beidou represent an important infrastructure to our society. They provide position and timing for numerous applications. A GNSS is a rather complex system consisting of around 30 satellites, a number of monitor stations, plus a control center. Billions of GNSS receivers represent the user segment. The receivers and the monitor stations receive a weak satellite radio signal and thus are susceptible to interference like jamming or spoofing. This paper outlines the core operation principles of satellite navigation to describe those kind of interference and to analyze the impacts. Different types of interference attacks result in different effects at the target receiver. The attack schemes are categorized within this paper. Reported incidents are summarized as well as the potential impact of GNSS vulnerability on critical infrastructure. Well known countermeasures at user receiver level or at system level are outlined and discussed for their suitability. The political and socioeconomic context of GNSS vulnerability is described emphasizing the large impact of a potential disruption of the GNSS service.

Known Vulnerabilities of Global Navigation Satellite Systems, Status, and Potential Mitigation Techniques

We propose a group signature scheme with constant-size public key and signature length that does not require trapdoor. So system parameters can be shared by multiple groups belonging to different organizations. The scheme is provably secure in the formal model recently proposed by Bellare, Shi and Zhang (BSZ04), using random oracle model, Decisional Bilinear Diffie-Hellman and Strong Diffie-Hellman assumptions. We give a more efficient variant scheme and prove its security in a formal model which is a modification of BSZ04 model and has a weaker anonymity requirement. Both schemes are very efficient and the sizes of signatures are approximately one half and one third, respectively, of the sizes of the well-known ACJT00 scheme. We also use the schemes to construct a traceable signature scheme.

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Efficient and provably secure trapdoor-free group signature schemes from Bilinear pairings

Portable security transaction protocol

A public licensing infrastructure (PLI) for a digital rights management (DRM) system is described. In an implementation, a method includes generating a formal license for content. The formal license includes a decryption key for decrypting the content and access rules for accessing the content. A plurality of license authorities is configured to provide a plurality of partial licenses. The plurality of partial licenses is combinable to form the formal license. Each license authority provides a respective partial license.

Digital rights management system

As RFID-tagged systems become ubiquitous, the acceptance of this technology by the general public necessitates addressing related security/privacy issues. The past six years have seen an increasing number of publications in this direction, specifically using cryptographic approaches. We consider a stream of publications among these that consider mutual authentication of tag and reader, and identify some existing vulnerabilities.

RFID mutual authentication protocols

The increased functionality of EPC Class1 Gen2 (EPCGen2) is making this standard a de facto specification for inexpensive tags in the RFID industry. Recently three EPCGen2 compliant protocols that address security issues were proposed in the literature. In this paper we analyze these protocols and show that they are not secure and subject to replay/impersonation and statistical analysis attacks. We then propose an EPCGen2 compliant RFID protocol that uses the numbers drawn from synchronized pseudorandom number generators (RNG) to provide secure tag identification and session unlinkability. This protocol is optimistic and its security reduces to the (cryptographic) pseudorandomness of the RNGs supported by EPCGen2.

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Secure EPC Gen2 Compliant Radio Frequency Identification

A methodology and system is used to facilitate the exchange of valued electronic information in a confidential, fair, and efficient manner. Either of two protocols can be employed that used encryption and electronic signatures to effectively guarantee origin and identity of sender and receiver in the exchange of valued information and requires timely response by both sender and receiver. The protocols rely upon one or a plurality of postal agents (servers) to provide secured online exchange of the information by arranging an efficient validation of the required signatures and information being exchanged between the sender and receiver. In the event of a breakdown in the exchange between sender and receiver, the use of a trusted third party (TTP) allows for fair and pre-agreed arbitration based upon the encrypted information and electronic signatures of the sender and receiver. The method does not require the use of the TTP unless a dispute arises.

Intermediated delivery scheme for asymmetric fair exchange of electronic items

This paper analyzes the modified Nyberg-Rueppel signature scheme (mNR), proving it secure in the Generic Group Model (GM). We also show that the security of the mNR signature is equivalent (in the standard model) to that of a twin signature [32], while achieving computational and bandwidth improvements. As a provably secure signature scheme, mNR is very efficient. We demonstrate its practical relevance by providing an application to the construction of a provably secure, self-certified, identity-based scheme (SCID). SCID schemes combine some of the best features of both PKIbased schemes (functionally trusted authorities, public keys revocable without the need to change identifier strings) and ID-based ones (lower bandwidth requirements). The new SCID scheme matches the performance achieved by the most efficient ones based on the discrete logarithm, while requiring only standard security assumptions in the Generic Group Model.

/pdf/a-provably-secure-nyberg-rueppel-signature-variant-with-2u02g3pyh2.pdf

A Provably Secure Nyberg-Rueppel Signature Variant with Applications.

/pdf/secure-epc-gen2-compliant-radio-frequency-identification-10h0c851i1.pdf

Breno de Medeiros

Papers

Secure EPC Gen2 Compliant Radio Frequency Identification

Intermediated delivery scheme for asymmetric fair exchange of electronic items

A Provably Secure Nyberg-Rueppel Signature Variant with Applications.

Secure EPC Gen2 compliant Radio Frequency Identification.