Ivanov I. The research on information protection methods in dynamic peer group environments

The thesis is devoted to the problem of construction of the prototype of software system, whose main purpose is providing the capabilities of protection of the information kept and transferred within dynamic peer group environments. The paper formalizes trust relations in group environments; the group type of digital signatures infrastructures and the Lee-Chang threshold signature algorithm adaptation to be used within such infrastructures are proposed. The developed modifications of digital signing and big numbers primality checking algorithms according to the RSA scheme provide the ability of delegation of computationally costly operations to the serving device without revealing secret parameters of the private key. A set of key agreement delegation algorithms based on the "contributions tree" data structure for heterogeneous and large environments is proposed. A distributed cryptographic algorithms productivity prediction method for dynamic groups that considers the environment as a queuing system is defined. Key words: group environment, information protection, delegation, algorithms productivity, digital signature infrastructure, key agreement, peer group.