A modified CLIQUES key agreement protocol for secure multicast

In a secured multicast application, members may join or leave frequently. Hence, key management is one of the most challenging problems. A practical and scalable key management requires high security features, efficient key distribution, low key-storage cost, and small processing overhead. CLIQUES (1-5) scheme was proposed to handle contributory key agreement. It extends the two-party Diffie-Hellman (6) algorithm to allow a group of members to "agree" upon a symmetric group key. Among the existing key management approaches, CLIQUES has the lowest cost in establishing the common session key. It also imposes less processing overhead in the user machine. The main drawback of CLIQUES is that a large number of re-key messages have to be exchanged among members when there is a membership change. The number of messages exchanged is proportional to the size of the membership. Consequently, CLIQUES is not very scalable and cannot support large group of members. In this thesis, we proposed a Static CLIQUES, in which, a static group controller is introduced to reduce the complexity of status synchronization process within the group when there is a membership change. The number of keys stored in each member is smaller than that of the original CLIQUES. In addition, the use of static group controller provides member privacy protection since individual member does not have direct contact with other members. We also proposed a hierarchical CLIQUES structure to support a large number of members by sub-grouping them logically into a hierarchical key tree. It is more scalable than dynamic CLIQUES. The size of re-key message being distributed is found to be comparable with hierarchical key tree approach (7-11).

A modified CLIQUES key agreement protocol for secure multicast

In a secured multicast application, members may join or leave frequently. Hence, key management is one of the most challenging problems. A practical and scalable key management requires high security features, efficient key distribution, low key-storage cost, and small processing overhead. CLIQUES (1-5) scheme was proposed to handle contributory key agreement. It extends the two-party Diffie-Hellman (6) algorithm to allow a group of members to "agree" upon a symmetric group key. Among the existing key management approaches, CLIQUES has the lowest cost in establishing the common session key. It also imposes less processing overhead in the user machine. The main drawback of CLIQUES is that a large number of re-key messages have to be exchanged among members when there is a membership change. The number of messages exchanged is proportional to the size of the membership. Consequently, CLIQUES is not very scalable and cannot support large group of members. In this thesis, we proposed a Static CLIQUES, in which, a static group controller is introduced to reduce the complexity of status synchronization process within the group when there is a membership change. The number of keys stored in each member is smaller than that of the original CLIQUES. In addition, the use of static group controller provides member privacy protection since individual member does not have direct contact with other members. We also proposed a hierarchical CLIQUES structure to support a large number of members by sub-grouping them logically into a hierarchical key tree. It is more scalable than dynamic CLIQUES. The size of re-key message being distributed is found to be comparable with hierarchical key tree approach (7-11).

Group-Key Generation through Ternary Tree Based Rebuild Algorithm

Security plays essential role in any correspondence framework particularly in Group oriented correspondence. In Group oriented correspondence, entire correspondence will occur with the help of one secret key which is called Group Key. This gathering key must be changed at whatever point another part joins into the gathering just as a current part leaves from the gathering; which is known as rekeying. This gathering correspondence can be spoken to utilizing key tree. In case we utilize ternary tree, tallness of the tree will be expanded if the group members are more, so that rekeying activity takes additional time. Rather than ternary tree on the off chance that we use quad tree, so that the tree stature will be less, so that rekeying activity takes less time. So the correspondence will be increasingly secure and quicker. In this paper we are going to implement Ternary tree based Rebuild Algorithm

Influence of Drought on Foliar Water Uptake Capacity of Temperate Tree Species

Foliar water uptake (FWU) has been investigated in an increasing number of species from a variety of areas but has remained largely understudied in deciduous, temperate tree species from non-foggy regions. As leaf wetting events frequently occur in temperate regions, FWU might be more important than previously thought and should be investigated. As climate change progresses, the number of drought events is expected to increase, basically resulting in a decreasing number of leaf wetting events, which might make FWU a seemingly less important mechanism. However, the impact of drought on FWU might not be that unidirectional because drought will also cause a more negative tree water potential, which is expected to result in more FWU. It yet remains unclear whether drought results in a general increase or decrease in the amount of water absorbed by leaves. The main objectives of this study are, therefore: (i) to assess FWU-capacity in nine widely distributed key tree species from temperate regions, and (ii) to investigate the effect of drought on FWU in these species. Based on measurements of leaf and soil water potential and FWU-capacity, the effect of drought on FWU in temperate tree species was assessed. Eight out of nine temperate tree species were able to absorb water via their leaves. The amount of water absorbed by leaves and the response of this plant trait to drought were species-dependent, with a general increase in the amount of water absorbed as leaf water potential decreased. This relationship was less pronounced when using soil water potential as an independent variable. We were able to classify species according to their response in FWU to drought at the leaf level, but this classification changed when using drought at the soil level, and was driven by iso- and anisohydric behavior. FWU hence occurred in several key tree species from temperate regions, be it with some variability, which potentially allows these species to partly reduce the effects of drought stress. We recommend including this mechanism in future research regarding plant–water relations and to investigate the impact of different pathways used for FWU.

Ternary Tree Based Approach For Accessing the Resources By Overlapping Members in Cloud Computing

<p>In cloud computing, immediate access of resources is important due to cost incurred to customer by pay per use model of cloud computing. Usually resource is protected by using cryptography technique. The resource may be shared by multiple members in group. There can be overlapping members to access the multiple resources. Group key management is important to form the group key to access the resource. Group key formation time is crucial for immediate access of protected resource in cloud computing. Thus ternary tree based approach is proposed to form the key for overlapping members accessing resources. Membership event such as join and leave also considered. Through the analysis, it is found that computational overhead is reduced by 23% if ternary key trees are combined than independent ternary key trees. It is also observed that combined ternary key tree outperforms the combined binary key tree approach for group key formation by considering overlapping members. Security requirement analysis of group membership for key formation is also provided in the paper.</p>