Cryptographic scheme for group passwords distribution in steganographic systems

This paper proposes a new scheme of passwords distribution for user groups via a hidden communication channel. The previously known models explicitly demonstrated the presence of passwords and cannot be used in any hidden communication channel. The considered model assumes the presence of a coordinator who regulates the composition of the groups and is the source of the overwhelming proportion of messages. The composition of the groups is not known in advance and may change during transmission messages. It is assumed that the data transmitted in a container will consist of two parts: a service part, which contains information about groups and passwords, and a useful part, which contains the target message that encrypted with a group-password. The scheme is based on the Kronecker-Capelli theorem. To find a group password the subscriber-receiver, is included in the group, calculates the product of the roots of a joint system of linear algebraic equations. This system consists of n equations and contains n+1variables. For an outside subscriber, who is not included in the group, the system of equations has not a single solution. A subscriber in the group is able to calculate one variable by a predefined formula. Consequently, the system of equations for such subscriber has the unique solution. The paper describes the processes of changing a composition of groups: creating, adding a participant, removing. The removing users from a group is realized by reuniting members of the old group. The scheme provides the possibility of combining previously created subgroups into large group without significant overhead costs. The proposed scheme can be used in practice by some organization to manage its branches when communicating via hidden data transmission channels

On the Incorporation of Secure Filter in ICMetrics Group Communications

Secure group communications present a unique environment where there can be multiple clients and hosts are trying to communicate securely within the group. As the number of clients and hosts increases the complexity of the communication security also increases. Group communications are based on a dynamic environment where the clients may join or leave the group at any moment. Hence it is important to ensure that only permitted entities have access to the group and those that have left the group or are not part of the group have no access to the group communications. This paper explores the delineation of a secure communication filter function that is applicable to group communications and is based on the latest Integrated Circuits Metrics (ICMetrics). The proposed scheme is based on the use of hash functions. To test the scalability of the scheme it has been implemented using SHA1 and SHA2

GPRKEY - A NOVEL GROUP KEY REKEYING TECHNIQUE FOR MANET

A Mobile Ad hoc Network (MANET) is a collection of autonomous nodes or mobile devices that can arrange themselves in various ways and work without strict network administration. Ensuring security in mobile ad hoc networks is a challenging issue and most of the applications in mobile ad hoc networks involve group oriented communication. Mostly cryptographic techniques are used to provide the security to MANETs. Cryptographic techniques will not be efficient security mechanism if the key management is weak. The issue of packet loss in MANET that is caused due to multi casting and backward and forward secrecy results in mobility. Hence, we investigate on this issue and propose a method to overcome this scenario. On analysing the situation we find that frequent rekeying leads to huge message overhead and hence increases energy utilization. With the existing key management techniques it causes frequent disconnections and mobility issues. Therefore, an efficient multi casting group key management will help to overcome the above problems. In this paper we propose a novel group key rekeying technique named GPRKEY (Group key with Periodic ReKEYing) deal with scalability issue of rekeying and also analyze the performance of the newly proposed key management method using key trees. In this approach we use the periodic rekeying to enhance the scalability and avoid out of sync problems. We use sub trees and combine them using the merging algorithm and periodic re-keying algorithm. The GPRKEY is evaluated through NS-2 simulation and compared with existing key management techniques OFT (One-way Function Tree) and LKH (Logical Key Hierarchy). The security and performance of rekeying protocols are analyzed through detailed study and simulation