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In this paper, we propose a generalized scheme for the predistribution of keys. Calculations are performed in an arbitrary vector space. Key materials are formed based on vector space elements and symmetric operator over a vector space. Two particular cases of application of the proposed scheme are considered.

The symmetric encryption session key generation protocol based on the Shamir secret sharing scheme and the Blom key predistribution scheme is proposed. Predistribution of key materials through secure channels is used. Key calculation is based on symmetric polynomials from three variables. Key calculation is based on threshold scheme (3,4). The basic protocol for two participants was considered. A scheme for an arbitrary number of users has been summarized.

The problem of optimizing the security policy for the composite information system is formulated. Subject-object model for information system is used. Combining different types of security policies is formalized. The target function for the optimization task is recorded. The optimization problem for combining two discretionary security policies is solved. The case of combining two mandatory security policies is studied. The main problems of optimization the composite security policy are formulated. +50 CHMBOJIOB!!!

Implementation for the key preliminary distribution scheme in the continuous functions space is proposed. Key materials are formed based on linear differential operator. User characteristics are presented in the form of a harmonic series. We show that this approach allows you to develop a common encryption key. A linear differential operator is formed only from even order derivatives. Odd order derivatives do not affect the encryption key value.

A modification is presented of the scheme of preliminary Blom’s key distribution taking into account the direction of information flows. The modification makes it necessary to use a function of three variables. The function of forming key materials ceases to be symmetrical. An exponential form of this function was proposed, which does not increase the amount of key materials.

The implementation of mandatory distribution of access in distributed systems taking into account a user hierarchy is considered. The access control is based on the scheme of preliminary key distribution similar to KDP-scheme. The algorithm of building a family of subsets taking into account a user hierarchy was developed.

The article proposes a method for embedding digital watermarks into executable program code. A digital watermark is generated in the process RAM. Existing information structures, such as dynamic arrays and objects, are used to accommodate parts of the embedded message. The message embedding program modifies the size of the data structures. The digital watermark is placed in additional memory locations. Two approaches to the placement of digital watermarks are proposed. Arrays are ordered in lexicographic order. Parts of the embedded message are placed in arrays. There are no array names in the executable code. nformation for stegonographic analysis is not available. Arrays for embedding can also be selected in any order. Portions of the digital watermark are written to a dynamic unidirectional list. The unidirectional list is embedded in arrays. Embedding into objects of the same class is carried out using similar methods.

In the article, the KDP key pre-distribution scheme is modified for attribute access control. A scheme for implementing attribute-based access control on symmetric encryption is proposed. There are three participants in the scheme: a key distribution server, a subject, and a storage server. The key distribution server sends key content over secure channels when the system is initialized. The key materials content is determined by the attributes of the object and the subject. The storage server calculates the object ′s encryption key based on the object ′s key materials and attributes. The object is stored encrypted. If the subject has the necessary attributes, it can calculate the encryption key and access to object. If the subject does not have a sufficient set of attributes, the key cannot be computed and access is denied.

A modification of the KDP scheme for the distribution of encryption keys is considered as applied to a distributed computer system with a discretionary security model. Limited access is specified as forbidden channels of data transmission. The scheme of preliminary key distribution is designed in such a way that it is impossible for forbidden channels to create a key-pair for the data exchange. An example of the construction of the proposed scheme is presented.

The article discusses the approach to encoding information based on families of orthogonal polynoms. The discrete signal is represented as a superposition of orthogonal polynoms. This approach allows to be transmit the useful signal in a chaotic container without matching the parameters of the noise generators. Different orthogonal functions families are considered: trigonometric functions and, Lagrange polynomials. The parameters of orthogonal polynoms families have been studied to increase the stability and stealth of the signal. The computer experiment is made. The average number of decoding errors is calculated depending on the numerical integration step. Orthogonal polynomials require significantly larger calculations to decode the message.

In article the modification of the Blom's keys preliminary distribution scheme, considering the direction of information streams is suggested. For this modification it is necessary to use function from three variables. Function of formation of key materials will be the asymmetrical. The exponential form of this function which does not increase the volume of key materials is suggested.

The problem of optimal authorization of a user in a system with a role-based access control policy is considered. The main criterion is to minimize the risks of permission leakage. The choice of the role for authorization is based on the analytic hierarchy process. The substantiation of a choice of criteria for formation of a hierarchy of the first level is given. An algorithm for calculating weight coefficients is presented, based on the quantitative characteristics of the role graph and not dependent on subjective expert evaluations. The complexity is estimated and the scalability of the proposed algorithm is discussed

The possibility of use the keys preliminary distribution KDP-scheme for mandatory access control realization in the distributed systems with user's hierarchy is considered. The modified keys preliminary distribution algorithm is suggested. It is developed a method for creation of subsets family for solution this task.