Position-based cryptography has attracted lots of researchers’ attention. In the mobile Internet, there are lots of position-based security applications. For the first time, one new conception, positioning-protocol-based symmetric cryptography is proposed. Based on one secure positioning protocol, one symmetric model is proposed. In the model, positioning protocols are bound to symmetric cryptography tightly, not loosely. Moreover, we propose one concrete positioning-protocol-based symmetric scheme, its correctness is proved. To our best knowledge, it is the first positioning-protocol-based symmetric scheme.
Position-based cryptography has attracted lots of researchers’ attention. In the mobile Internet, there are lots of position-based security applications. For the first time, one new conception, positioning-protocol-based symmetric cryptography is proposed. Based on one secure positioning protocol, one symmetric model is proposed. In the model, positioning protocols are bound to symmetric cryptography tightly, not loosely. Moreover, we propose one concrete positioning-protocol-based symmetric scheme, its correctness is proved. To our best knowledge, it is the first positioning-protocol-based symmetric scheme.
Position-based cryptography has attracted lots of researchers' attentions. In mobile Internet, there are lots of position based security applications. For the first time, one new conception, position-based proxy signcryption is proposed. Based on a secure positioning protocol, one model of position-based proxy signcryption is proposed. In the model, positioning protocol is tightly bound to proxy signcryption, not loosely. Further, we propose one concrete position-based proxy signcryption scheme, its correctness is proved, and its security is also analyzed. As far as we know, it is the first position-based proxy signcryption scheme.
Position-based cryptography has attracted lots of researchers' attention. In the mobile Internet, there are many position-based security applications. For the first time, one new conception-proxy multi-signature binding positioning protocols, is proposed. Based on one secure positioning protocol, one model of the proxy multi-signature binding positioning protocols is proposed. In the model, positioning protocols are bound to proxy multi-signature tightly, not loosely. Further, we propose one scheme of proxy multi-signature binding positioning protocols. As far as we know, it is the first scheme of proxy multi-signature binding positioning protocols.
In our daily lives, people or devices frequently need to learn their location for many reasons as some services depend on the absolute location or the proximity. The outcomes of positioning systems can have critical effects e.g., on military, emergency. Thus, the security of these systems is quite important. In this thesis, we concentrate on many security aspects of position in cryptography. The first part of this thesis focuses on the theory of distance bounding. A distance bounding protocol is a two-party authentication protocol between a prover and a verifier which considers the distance of the prover as a part of his/her credential. It aims to defeat threats by malicious provers who try to convince that they are closer to the verifier or adversaries which seek to impersonate a far-away prover. In this direction, we first study the optimal security bounds that a distance bounding protocol can achieve. We consider the optimal security bounds when we add some random delays in the distance computation and let the prover involve distance computation. Then, we focus on solving the efficiency problem of public-key distance bounding because the public-key cryptography requires much more computations than the symmetric-key cryptography. We construct two generic protocols (one without privacy, one with) which require fewer computations on the prover side compared to the existing protocols while keeping the highest security level. Then, we describe a new security model involving a tamper-resistant hardware. This model is called the secure hardware model (SHM). We define an all-in-one security model which covers all the threats of distance bounding and an appropriate privacy notion for SHM. The second part of this thesis is to fill the gap between the distance bounding and its real-world applications. We first consider contactless access control. We define an integrated security and privacy model for access control using distance bounding (DB) to defeat relay attacks. We show how a secure DB protocol can be converted to a secure contactless access control protocol. Regarding privacy (i.e., keeping anonymity in a strong sense to an active adversary), we show that the conversion does not always preserve privacy, but it is possible to study it on a case by case basis. Then, we consider contactless payment systems. We design an adversarial model and define formally the contactless payment security against malicious cards and malicious terminals. Accordingly, we design a contactless payment protocol and show its security in our security model. The last part of this thesis focuses on positioning. We consider two problems related to positioning systems: localization and proof of location. In localization, a user aims to find its position by using a wireless network. In proof of location, a user wants to prove his/her position e.g., to have access to a system or authorize itself. We first formally define the problem of localization and construct a formal security model. We describe algorithms and protocols for localization which are secure in our model. Proof of location has been considered formally by Chandran et al. in CRYPTO 2009 and it was proved that achieving security is not possible in the vanilla model. By integrating the localization and the secure hardware model, we obtain a model where we can achieve proof of location.
Position-verification is the process of verifying the presence of a device at a certain position. This verification is secure when no adversaries can falsely claim to be present there. In this article sev-eral models for position-verification are reviewed. First, the Vanilla model is reviewed. This model is the most basic model for position-verification, for it does not impose limitations on the abilities or knowledge of the adversaries. We prove that no secure position-verification protocol can exist in the Vanilla model. Next, the Hidden-Base Model, in which the location of one or more of the verifiers is unknown, and the Moving-Base Model, in which a verifier is not stationary but moves uniformly at random, are reviewed. We prove that in both models, no secure position-verification protocol can exist, unless assumptions are made that would make these models inapplicable.
The provable security of secure positioning in position-based cryptography was investigated,and the provable secure model of secure positioning was established in the universally composable framework.According to the security requirements of secure positioning,the ideal functionality of secure positioning firstly was proposed.Then,the ideal functionality of bounded retrieval model was designed as one of the set-up assumptions in position-based cryptography.Lastly,the secure positioning protocol in 1-dimension space,as an example,could securely realize the functionality of secure positioning in the bounded retrieval model.