This paperwork is dedicated to research of k-length CRC value distribution for data interval with volume n. It is shown in research  that CRC value could be represented as a sum of special-way formed random vectors over k-dimension vector space GFk(2) over a two-element 0,1-field (GF(2)).If the message or errors are modeled using independent random 0,1 values sequences, CRC could be regarded as a sum of independent random vector components.
The paperwork examines CRC value distribution’s behavior under conditions of big n’s and fixed values of k. By means of character theory application we find the conditions of asymptotic unification of CRC distribution.
Asymptotic results could be applied for error estimation for various telecommunication protocols (e.g. USB, X.25, HDLC, Bluetooth, Ethernet and others).
The article analyzes possibilities of errors in telecommunication protocols using packet data transmission. Probabilistic model of a prolonged-action additive interference is represented as a sequence of executions of independent interference blocks with definite length. The paper shows that in certain conditions concerning a polynomial of degree k, used for creation of CRC code, with block size s, probability of error occurrence α is close to 2-k and doesn’t depend on s if distortion probability P1 is significant. It is demonstrated that for low values of P1=δ/n, δ>0, CRC error probability depends on s. Authors make an example of an interference with s = k, where error probability α is higher than 2^(-k) value (δ2^(k-1))/k times, therefore α=δ/2k and CRC is not efficient.
Control sum mechanism efficiency research aimed at distortion revealing in a message being transmitted is a relevant task that is solved using different possible information transfer operation condition models.
In the paper distortions are modelled as an overlay of noise component with low signal/noise ratio , which poses most practical interest. Considered class of control sums is related to message consistency control mechanisms which are implemented, in particular, in TCP protocol. Functional dependency of control sum error probability from value is acquired for latter’s low value.
The basic principle of this article is structured representation of computer technologies. Application of this principle shows that any independent part of information computing system could be represented as a set of connection hardware units and different computers with specialized roles in the system. The items of the set, in turn, are operated through an external control subsystem. It is shown that currently the main issue of information security is to reach the needed level of availability and invulnerability to computer attacks.
We consider a variant of a neural symmetric cipher, describe its probabilistic model. We show that this cipher is equivalent to the proportional substitution cipher. We propose an algorithm for reconstruction of a plaintext from cipher text, using properties of the space of enciphered characters.
The peculiarities of the legal regulation of civil and building a system of civil protection of the computer information in the Russian Federation at the present time. The concept of computer information is subject to a comprehensive analysis by application of the law on electronic documents and computer programs (databases).
The paper considers certain probability-theoretic models of packet mode-transferred information distortions. Attention is drawn mainly to distortions, including possible interferences influencing multiple transfer cycles. Distortions are modeled by a consequential impacts that are defined by dependent random variables. K-dimensioned values of CRC, respectively allow representation as a sum of k-dimensioned independent random variables.
In some cases it is possible to bring them to a sum of independent terms in a k-dimensioned vector space over a two-element field and, afterwards, apply to them existing limit theorems dealing with convergence to uniform distributions.
The paper discusses prospects for impacts stretching to m cycles of acquiring convergence conditions for CRC distribution as a sum of m-dependent terms or ones not interconnected to a non-homogeneous Markov chain.
Enhanced electronic signature (hereinafter ES) application while transmitting a message over telecommunication channels reveals even most minor (down to single-bit) message change.
Insignificant distortions cause complete change of hash-function's result and therefore, lead to non-confirmation of ES. Meaning of the information held in file being transmitted may be uninfluenced by these distortions but totally ruin its legal meaning and mean sending the whole message anew. The situation tends to become more complicated in light of perspective legal-meaning data volume increase.
Thereupon arises the issue of the maximum possible size of a message transferred distortion-free over telecommunication networks based on modern network protocols of different layers. In the following network protocols are considered: Ethernet (Token Ring, FDDI), IP, TCP. Every one of them allows non-zero probability of distorted packet's occasional admission despite the control means. If the number of packets increases sufficiently this probability may become significant. The author proposes to evaluate this probability in low-strength binary white noise possibility modeling conditions.
Using the model proposed the distortion-free message size estimation is made. For the protocols mentioned it is over 1012 bytes.
Some tree-hashing modes are considered. The main requirements to tree-hashing modes are formulated.
In this paper a generalization of the classical birthday problem for the case of several independent samples of arbitrary power is considered. Exact and asymptotic expressions describing the probability of the intersection of these samples are obtained.
In this article the estimation of Mahlanobis's distance" is observed, in conditions of dual channel receiving of binary signal. The biggest value of the probability value Pn p is corresponded to the biggest Mahlanobis's distance. The importance of estimation value is postulated by the size of controlling zone that is necessary before being provided the secured state of processing information, which is existed in spurious emission and is regulated by recommendations of FSTEK of Russia. Unlike to works made and published before the algorithms of estimation of value Prp , which aren't using the information about training, binary, referent sequence, are proposed.
Two models of the tree modes of hash functions are introduced. For each model algorithms of computing of the hash code are formulated and their numerical characteristics are obtained. In terms of the constructed models we classify some existing algorithms for parallel hashing and identify some weaknesses of corresponding primitives.
In this work we present two new protocols for secure management of remote objects. These protocols are released in group of points of elliptic curve, defined over finite field, with usage of russian cryptography standards.
A comparative analysis of the probability characteristics of the test algorithm and the development of key reference model is done. A statistical method for determining nonequiprobability generated key sequence is proposed.
Sufficient conditions under which the periods of the sequences of maps generator IA divisible by 2n.