The secure transfer of Keys between two parties, is one of the primary problems in cryptography. The possibility that the Key can be manipulated or intercepted by way of an eavesdropper is the cause for the concern. A promising way to this problem is Quantum Key distribution (QKD). The secure distribution of Keys that may be used to encrypt and decrypt messages is made feasible by this approach, which makes use of the idea of quantum mechanics. QKD offers a degree of protection that can not be done by means of classical cryptography techniques, and has remarkable capability for application in a scope of fields in which secure correspondence is crucial. QKD is a field of study that has brought various conventions pointed toward empowering the safe alternate of cryptographic Keys between two parties, Alice and Bob. Two Key protocols within this field are the BB84 which was designed by Bennett and Brassard and E91 which was proposed by Ekert. While other protocols have been developed, many draw inspiration from these two foundational approaches. We focused specifically on the E91 protocol and explored its potential for the safe transfer of entangled pairs within computer networks. This protocol utilizes entanglement between particles as a means of verifying the security of the Key exchange. Our investigation centered around testing the entanglement swapping for two particles using the E91 protocol, with the aim of developing a novel method for the secure transmission of entangled pairs via computer networks. Our findings suggest promising avenues for future work in implementing secure entanglement swapping in practical applications.

Random Key distribution (RKD) schemes have been widely accepted to enable low-cost secure communications in Wireless Sensor Networks (WSNs). However, efficiency of secure link establishment comes with the risk of compromised communications between benign nodes by adversaries who physically capture sensor nodes. The challenge is to enhance resilience of WSN against node capture, while maintaining the flexibility and low cost features of RKD schemes. We address this problem by proposing an effective technique, namely KDel, which don’ t require any special-purpose hardware or expensive computations. We demonstrate that our approach significantly increases the resilience of RKD schemes against node capture at the cost of a little communications, while maintaining network connectivity at the same level. Moreover, our scheme is generally applicable as it can improve the resilience of any RKD scheme.

Sybil attacks pose a serious threat for Wireless Sensor Networks (WSN) security. They can create problems in routing, voting schemes, decision making, distributed storage and sensor re-programming. In a Sybil attack, the attacker masquerades as multiple sensor identities that are actually controlled by one or a few existing attacker nodes. Sybil identities are fabricated out of stolen Keys, obtained by captured benign nodes. Existing Sybil defensive mechanisms suffer from the restricted sensor network size, or cause excessive resource consumption for the sensor network. In this work we propose a Sybil node detection mechanism, based on Random Key distribution (RKD) schemes that can cope with large network sizes and minimize the waste of resources. We explain the techniques each node can use in a network running q-composite RKD to detect Sybil identities and restrict their number. Our method requires no trust to other sensors, which is important to defend against the attack.

Recently, the laws of quantum physics have amazed classical cryptography and aided researchers to provide secure communications in presence of adversaries.In this paper we present a novel weak blind signature scheme whose security is guaranteed by fundamental principles of quantum physics. Despite previous schemes which are taking advantage of quantum entangled states, our proposed quantum blind signature relies only on Quantum Key distribution (QKD) protocol. We show throughout this paper that our proposed quantum weak blind signature achieves a good position in security and reliability. In addition, it is feasible for the proposed scheme to become commercialized with current technology. Hence, it can be widely used for e-payment, e-government, e-business and etc.

Rural tourism is considered as a process of rural development that by creating complementary agricultural activities, provides economic development through raising the ability to generate income, create jobs, and consequently, sustainable livelihoods. In this regard, the purpose of this paper is to examine the effects of rural tourism income distribution in different economic sectors. For this purpose, the social accounting matrix (SAM) of 2006 and the multipliers analysis resulting from this matrix have been used. The advantages of using this method are the possibility of study the effects of income distribution of rural households by sections. By taking into account the totality of the economy, this model encompasses all direct and indirect effects on economic and social sectors. The results show that the development of rural tourism sub-sectors has a positive effect on the distribution of rural household income.

One of the obvious reasons for most disorders in network service provisioning is network path congestion. Congestion avoidance in today's networks is too costly and sometimes impossible. With the introduction of SDN, centralizing the equipment's control plane has become possible. This paper presents an enhanced method named ESV-DBRA to avoid congestion in multi-tenant SDN networks. At first, ESV-DBRA monitors the traffic load and delay of all network paths for each tenant individually. Then, by merging the parameters obtained from the monitoring, the Service Level Agreements (SLA), and a novel proposed cost function, it calculates the cost of the network paths per tenant. As a result, traffic for each tenant is routed through the path/paths at the lowest possible cost from the tenant's perspective. Next, the bandwidth quotas will be calculated and assigned to the tenants over their optimal routes. Afterward, whenever congestion is likely to occur in a path, ESV-DBRA automatically changes the route or bandwidth of the tenants' traffic related to this path to avoid congestion. Related algorithms are also proposed.Eventually, simulations show that the proposed method effectively increases bandwidth utilization by 10.76%.