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A set of technologies, that use radio waves for identifying people or objects, is called radio frequency identification system or RFID. RFID performance depends on tag and reader devices which use radio waves to communicate to each other. In some applications of RFID systems, the proof of concurrent presence for a number of objects or persons together in a given time is crucial. Grouping proof protocols are designed to address these needs, in fact grouping proof shows that two or more tags are evaluated by a reader simultaneously. This proof must be verified by the corresponding verifier. In this article this type of protocols are introduced and analyzed. At the first, the idea of designing a grouping proof is presented and then related protocols and their security analysis are presented. Finally, a comparison between protocols is provided.

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With the increase in attacks, the different mechanisms in different layers of defense are applied in order to detect and prevent attacks. In this case we are encountered with massive amounts of alerts with low level and scattered information. Alert correlation is one of the solutions that are used to combine alerts and create a high level view of under controlled network security situations, and a lot of researches have been done in this field. In this paper, we describe the OSSIM and introduce its features. In addition with a combined approach to the alert correlation problem, a new categorization is done on the scientific researches and with respect to these researches, we described the process of alert correlation in the OSSIM and established a correspondence between components of the OSSIM and one of the researches. In most researches the focus is on the alerts correlation of intrusion detection systems, we have shown in this paper that the other resources are effective in multi-stage attacks correlation.

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In this paper, a cooperative scheme for secure device to device (D2D) communications underlaying cellular networks is proposed. In our scheme, the cellular base station (BS) wants to transmit its information to a cellular user (CU). Meanwhile, two devices want to communicate directly using the same spectrum used by cellular network with the help of some decode-and-forward (DF) relay nodes. In addition, there exists a malicious user which wants to eavesdrop on information transmission of D2D pair. The transmit power of the transmitter of the D2D pair (TD2D) and the relays is limited such that the outage performance of cellular network is satisfied. We study the performance of the proposed scheme, which is measured based on the outage probability, and obtain the closed form expression for the outage probability for the optimal relay selection scheme. Finally, the performance of the proposed scheme is evaluated using simulations.