THE END of the 20th century was marked by an avalanche-like spread of the Internet: access speeds grew exponentially, more and more new territories were covered, and it was possible to establish a fast connection via the network between almost any two points in the world. But the transfer of information was not secure; attackers could intercept, steal, or change it. At this time, the idea of ​​​​organizing a reliable channel that would use publicly available communications for communication, but would protect the transmitted data through the use of cryptographic methods, began to gain popularity. The cost of organizing such a channel was many times less than the cost of laying and maintaining a dedicated physical channel. Thus, the organization of a secure communication channel became available to medium and small enterprises and even individuals.

ViPNet system

The ViPNet system provides transparent protection of information flows of any applications and any IP protocols for both individual workstations, file servers, application servers, routers, remote access servers, etc., and segments of IP networks. At the same time, it functions as a personal firewall for each computer and a firewall for IP network segments.

The key structure is of a combined nature, has both a symmetric key distribution scheme, which allows for a rigid centralized management system, and an open key distribution system, and is used as a trusted environment for PKI operation. Application programs of the ViPNet system additionally provide secure real-time services for broadcast messaging, conferencing, and negotiations; for services for guaranteed delivery of postal correspondence with electronic signature procedures and access control to documents; for autoprocessing services for automatic file delivery. In addition, separately designed cryptographic functions of the kernel (signing and encryption) and implemented support for the MS Crypto API, if necessary, can be built directly into various application systems (for example, electronic document management systems).

The ViPNet system software operates in Windows and Linux operating environments.

ViPNet CUSTOM

Each ViPNet CUSTOM component contains a built-in firewall and a system for monitoring application network activity, which allows you to obtain a reliable distributed system of firewalls and personal firewalls.

To resolve possible conflicts of IP addresses in local networks included in a single secure network, ViPNet CUSTOM offers a developed system of virtual addresses. In many cases, this makes it possible to simplify the configuration of the user's application software, since the overlay virtual network with its virtual addresses will hide the real complex structure of the network. ViPNet CUSTOM supports inter-networking capabilities, which allows you to establish the necessary secure communication channels between an arbitrary number of secure networks built using ViPNet CUSTOM. In addition, the system ensures information protection in modern multi-service communication networks providing IP telephony and audio and video conferencing services. Traffic prioritization and H.323, Skinny protocols are supported.

Protection of communication channels

Protecting information in communication channels is the most important issue in organizing security in an enterprise. Today, many methods are used to successfully protect information transmitted through communication channels within a corporation or to the outside world.

Protection of communication channels and its main methods

Protection of communications and information is carried out using two methods. This is a protection method based on physically restricting access directly to the communication channel, as well as signal conversion (encryption), which will not allow an attacker to read the transmitted information without a special key.

In the first method, protection of the communication channel is organized by restricting access to the equipment through which information is transmitted. Used mainly in large companies and government agencies. This method only works if the information does not reach the outside world.

In all other cases, information in communication channels is protected through data encryption. Encryption of transmitted information, if we talk about classical computer networks, can be performed at various levels of the OSI network model. Most often, data conversion occurs at the network or application levels.

In the first case, data encryption is carried out directly on the equipment, which is the sender of the information, and decryption is carried out on the receiver. This option will most effectively protect the transmitted data, but its implementation requires third-party software that would work at the application level.

In the second case, encryption is carried out directly at the nodes of the communication channel in a local or global network. This method of protecting communications is less effective than the first, and for the proper level of information protection it requires the implementation of reliable encryption algorithms.

Protection of information in communication channels is also organized when constructing VPN virtual channels. This technology allows you to organize a secure connection with the specified encryption over a special virtual channel. This technology ensures the integrity and confidentiality of information transmitted over the communication channel.

Communication channel protection devices

Such devices include:

• all kinds of mufflers,
• communication suppressors,
• antibugs,
• detectors,

thanks to which you can take control of the state of the air inside or outside the enterprise. This is one of the effective methods of protecting communications at an early stage to neutralize unauthorized access to the source of information.

JSC "VOLGA UNIVERSITY NAMED AFTER V.N. TATISHCHEV"

FACULTY OF INFORMATION SCIENCE AND TELECOMMUNICATIONS

Department of Informatics and Control Systems

COURSE WORK

in the discipline: “Methods and means of protecting computer information”

subject: " Protection of communication channels»

IS-506 group student

Utyatnikov A.A.

Teacher:

M.V. Samokhvalova

Tolyatti 2007

Introduction

Protection of information in communication channels and creation of secure telecommunication systems

Remote access to information resources. Protection of information transmitted over communication channels

1 Solutions based on certified crypto gateways

2 Solutions based on the IPSec protocol

Information security technologies in information and telecommunication systems (ITS)

Conclusion

Introduction

Protection (security) of information is an integral part of the general problem of information security, the role and significance of which in all spheres of life and activity of society and the state is steadily increasing at the present stage.

Production and management, defense and communications, transport and energy, banking, finance, science and education, and the media increasingly depend on the intensity of information exchange, completeness, timeliness, reliability and security of information.

In this regard, the problem of information security has become a subject of acute concern for heads of government bodies, enterprises, organizations and institutions, regardless of their organizational, legal forms and forms of ownership.

The rapid development of computer technology has opened up unprecedented opportunities for humanity to automate mental work and led to the creation of a large number of various kinds of automated information, telecommunications and control systems, and to the emergence of fundamentally new, so-called information technologies.

When developing approaches to solving the problem of computer and information security, one should always proceed from the fact that protecting information and a computer system is not an end in itself. The ultimate goal of creating a computer security system is to protect all categories of subjects directly or indirectly involved in information interaction processes from causing them significant material, moral or other damage as a result of accidental or intentional impacts on information and systems for its processing and transmission.

1. Protection of information in communication channels and creation of secure

telecommunication systems

In the context of growing integration processes and the creation of a single information space in many organizations, LANIT proposes to carry out work to create a secure telecommunications infrastructure connecting remote offices of companies into a single whole, as well as ensuring a high level of security of information flows between them.

The technology used for virtual private networks makes it possible to unite geographically distributed networks using both secure dedicated channels and virtual channels passing through global public networks. A consistent and systematic approach to building secure networks involves not only protecting external communication channels, but also effectively protecting internal networks by isolating closed internal VPN circuits. Thus, the use of VPN technology allows you to organize secure user access to the Internet, protect server platforms and solve the problem of network segmentation in accordance with the organizational structure.

Protection of information during transmission between virtual subnets is implemented using asymmetric key algorithms and electronic signatures that protect information from forgery. In fact, data to be transmitted intersegmentally is encoded at the output of one network and decoded at the input of another network, while the key management algorithm ensures its secure distribution between end devices. All data manipulations are transparent to applications running on the network.

2. Remote access to information resources. Protection

information transmitted via communication channels

When interconnecting between geographically remote company objects, the task arises of ensuring the security of information exchange between clients and servers of various network services. Similar problems occur in wireless local area networks (WLAN), as well as when remote subscribers access the resources of a corporate information system. The main threat here is considered to be unauthorized connection to communication channels and interception (listening) of information and modification (substitution) of data transmitted through channels (mail messages, files, etc.).

To protect data transmitted over these communication channels, it is necessary to use appropriate cryptographic protection tools. Cryptographic transformations can be carried out both at the application level (or at the levels between application protocols and the TCP/IP protocol) and at the network level (conversion of IP packets).

In the first option, encryption of information intended for transportation via a communication channel through an uncontrolled territory must be carried out at the sending node (workstation - client or server), and decryption - at the recipient node. This option involves making significant changes to the configuration of each interacting party (connecting cryptographic protection means to application programs or the communication part of the operating system), which, as a rule, requires large costs and installation of appropriate protection means on each node of the local network. Solutions for this option include the SSL, S-HTTP, S/MIME, PGP/MIME protocols, which provide encryption and digital signature of email messages and messages transmitted using the http protocol.

The second option involves installing special tools that carry out crypto-transformations at the points of connection of local networks and remote subscribers to communication channels (public networks) passing through uncontrolled territory. When solving this problem, it is necessary to ensure the required level of cryptographic data protection and the minimum possible additional delays during their transmission, since these tools tunnel the transmitted traffic (add a new IP header to the tunneled packet) and use encryption algorithms of different strengths. Due to the fact that the tools that provide crypto-transformations at the network level are fully compatible with any application subsystems running in the corporate information system (they are “transparent” to applications), they are most often used. Therefore, in the future we will dwell on these means of protecting information transmitted over communication channels (including over public networks, for example, the Internet). It is necessary to take into account that if cryptographic information protection means are planned for use in government agencies, then the issue of their choice should be decided in favor of products certified in Russia.

.1 Solutions based on certified crypto gateways

To implement the second option and ensure the confidentiality and reliability of information transmitted between company facilities via communication channels, you can use certified crypto gateways (VPN gateways). For example, Continent-K, VIPNet TUNNEL, ZASTAVA-Office of the companies NIP Informzaschita, Infotex, Elvis+. These devices provide encryption of transmitted data (IP packets) in accordance with GOST 28147-89, and also hide the structure of the local network, protect against outside penetration, route traffic and have certificates from the State Technical Commission of the Russian Federation and the FSB (FAPSI).

Crypto gateways allow remote subscribers to securely access the resources of the corporate information system (Fig. 1). Access is made using special software that is installed on the user’s computer (VPN client) to ensure secure interaction between remote and mobile users with the crypto gateway. The crypto gateway software (access server) identifies and authenticates the user and communicates with the resources of the protected network.

Figure 1. - “Remote access via a secure channel with

using a crypto gateway"

Using crypto gateways, you can form virtual secure channels in public networks (for example, the Internet), guaranteeing confidentiality and reliability of information, and organize virtual private networks (Virtual Private Network - VPN), which are an association of local networks or individual computers connected to a public network. use into a single secure virtual network. To manage such a network, special software (control center) is usually used, which provides centralized management of local security policies for VPN clients and crypto gateways, sends key information and new configuration data to them, and maintains system logs. Crypto gateways can be supplied as software solutions or as hardware-software systems. Unfortunately, most of the certified crypto gateways do not support the IPSec protocol and, therefore, they are not functionally compatible with hardware and software products from other manufacturers.

.2 IPSec based solutions

The IP Security (IPSec) protocol is the basis for building network-level security systems; it is a set of open international standards and is supported by most manufacturers of network infrastructure protection solutions. The IPSec protocol allows you to organize secure and authentic data flows (IP packets) at the network level between various interacting principals, including computers, firewalls, routers, and provides:

· authentication, encryption and integrity of transmitted data (IP packets);

· protection against retransmission of packets (replay attack);

· creation, automatic updating and secure distribution of cryptographic keys;

· use of a wide range of encryption algorithms (DES, 3DES, AES) and data integrity monitoring mechanisms (MD5, SHA-1). There are software implementations of the IPSec protocol that use Russian encryption algorithms (GOST 28147-89), hashing (GOST R 34.11-94), electronic digital signature (GOST R 34.10-94);

· authentication of network interaction objects based on digital certificates.

The current set of IPSec standards includes the core specifications defined in RFCs (RFC 2401-2412, 2451). Request for Comments (RFC) is a series of documents from the Internet Engineering Task Force (IETF), begun in 1969, containing descriptions of the Internet protocol suite. The system architecture is defined in RFC 2401 "Security Architecture for Internet Protocol", and the specifications of the main protocols are in the following RFCs:

· RFC 2402 “IP Authentication Header” - specification of the AH protocol, which ensures the integrity and authentication of the source of transmitted IP packets;

· RFC 2406 “IP Encapsulating Security Payload” - ESP protocol specification that ensures confidentiality (encryption), integrity and source authentication of transmitted IP packets;

· RFC 2408 “Internet Security Association and Key Management Protocol” - specification of the ISAKMP protocol, which ensures parameter negotiation, creation, modification, destruction of secure virtual channels (Security Association - SA) and management of the necessary keys;

· RFC 2409 "The Internet Key Exchange" - a specification of the IKE protocol (includes ISAKMP), which provides parameter negotiation, creation, modification and destruction of SAs, negotiation, generation and distribution of the key material necessary to create the SA.

The AH and ESP protocols can be used both together and separately. The IPSec protocol uses symmetric encryption algorithms and corresponding keys to ensure secure network communication. The mechanisms for generating and distributing such keys are provided by the IKE protocol.

Secure Virtual Channel (SA) is an important concept in IPSec technology. SA is a directed logical connection between two systems supporting the IPSec protocol, which is uniquely identified by the following three parameters:

· secure connection index (Security Parameter Index, SPI - a 32-bit constant used to identify different SAs with the same recipient IP address and security protocol);

· IP address of the recipient of IP packets (IP Destination Address);

· security protocol (Security Protocol - one of the AH or ESP protocols).

As an example, Figure 2 shows a remote access solution over a secure channel from Cisco Systems based on the IPSec protocol. Special Cisco VPN Client software is installed on the remote user's computer. There are versions of this software for various operating systems - MS Windows, Linux, Solaris.

Figure 2. - “Remote access via a secure channel with

using a VPN concentrator"

The VPN Client interacts with the Cisco VPN Series 3000 Concentrator and creates a secure connection, called an IPSec tunnel, between the user's computer and the private network behind the VPN concentrator. A VPN concentrator is a device that terminates IPSec tunnels from remote users and manages the process of establishing secure connections with VPN clients installed on user computers. The disadvantages of this solution include the lack of support by Cisco Systems for Russian encryption, hashing and electronic digital signature algorithms.

3. Information security technologies in information technology

telecommunication systems (ITS)

telecommunications protection information channel communication

Effective support of public administration processes using tools and information resources (IIR) is possible only if the system has the property of “security”, which is ensured by the implementation of a comprehensive information security system, including basic security components - an access control system for ITS facilities, a video surveillance and information security system.

The cornerstone of an integrated security system is an information security system, the conceptual provisions of which arise from the design features of the system and its constituent subsystems and the concept of a “protected” system, which can be formulated as follows:

A secure ITS is an information and telecommunication system that ensures the stable execution of the target function within the framework of a given list of security threats and the model of the intruder’s actions.

The list of security threats and the pattern of actions of the violator are determined by a wide range of factors, including the operational process of the ITS, possible erroneous and unauthorized actions of service personnel and users, equipment failures and malfunctions, passive and active actions of violators.

When building an ITS, it is advisable for public authorities (GBOs) to consider three basic categories of threats to information security that can lead to disruption of the system’s main target function - effective support of public administration processes:

· failures and malfunctions in the system hardware, emergency situations, etc. (events without human participation);

· erroneous actions and unintentional unauthorized actions of service personnel and system subscribers;

Unauthorized actions of the violator may relate to passive actions (interception of information in a communication channel, interception of information in technical leakage channels) and active actions (interception of information from storage media with a clear violation of the rules of access to information resources, distortion of information in a communication channel, distortion, including destruction of information on storage media in clear violation of the rules of access to information resources, introduction of disinformation).

The violator may also take active actions aimed at analyzing and overcoming the information security system. It is advisable to classify this type of action as a separate group, since, having overcome the security system, the intruder can perform actions without clearly violating the rules of access to information resources.

In the above type of actions, it is advisable to highlight possible actions aimed at introducing hardware and software components into ITS equipment, which is primarily determined by the use of foreign equipment, components and software.

Based on the analysis of the ITS architecture and threats, a general architecture of the information security system can be formed, including the following main subsystems:

· information security system management subsystem;

· security subsystem in the information subsystem;

· security subsystem in the telecommunications subsystem;

· security subsystem for internetwork interaction;

· subsystem for identifying and countering the active actions of violators;

· a subsystem for identifying and countering possible hardware and software bookmarks.

It should be noted that the last three subsystems, in the general case, are components of the second and third subsystems, but taking into account the features formulated above, it is advisable to consider them as separate subsystems.

The basis of the information security system in the ITS and each of its subsystems is the Security Policy in the ITS and its subsystems, the key provisions of which are the requirements for the use of the following basic mechanisms and means of ensuring information security:

· identification and authentication of ITS subscribers, ITS equipment, processed information;

· control of information flows and information life cycle based on security labels;

· access control to ITS resources based on a combination of discretionary, mandatory and role-based policies and firewalling;

· cryptographic information protection;

· technical means of protection;

· organizational and regime measures.

The given list of protection mechanisms is determined by the goals of the information security system in the ITS, among which we will highlight the following five main ones:

· access control to ITS information resources;

· ensuring the confidentiality of protected information;

· monitoring the integrity of protected information;

· non-denial of access to information resources;

· readiness of information resources.

The implementation of the specified mechanisms and means of protection is based on the integration of hardware and software protection means into the hardware and software of the ITS and the processed information.

Note that the term “information” in ITS refers to the following types of information:

· user information (information necessary for management and decision-making);

· service information (information that provides control of ITS equipment);

· special information (information that ensures the management and operation of protective equipment);

· technological information (information that ensures the implementation of all information processing technologies in ITS).

In this case, all listed types of information are subject to protection.

It is important to note that without the use of automated information security system management tools, it is impossible to ensure stable operation of the security system in a geographically distributed information processing system that interacts with both protected and non-protected systems in the ITS circuit and processes information of varying levels of confidentiality.

The main objectives of the information security management subsystem are:

· generation, distribution and accounting of special information used in security subsystems (key information, password information, security labels, access rights to information resources, etc.);

· configuration and management of information security tools;

· coordination of security policies in interacting systems, including special information;

· security system monitoring;

· updating the Security Policy in ITS taking into account different periods of operation, introducing new information processing technologies into ITS.

The implementation of the information security management subsystem requires the creation of a single control center that interacts with local security control centers for the telecommunications and information subsystems of the ITS, information security control centers in interacting networks and information security agents at system facilities.

The architecture of the information security management system should be virtually identical to the architecture of the ITS itself, and from the point of view of its implementation, the following principles should be followed:

· the information security control center and local control centers must be implemented on dedicated hardware and software using domestic means;

· security management agents must be integrated into the hardware and software of the system’s workplaces with the possibility of independent control from them by the center and local centers.

The information security subsystem in the ITS information subsystem is one of the most complex subsystems both in terms of protection mechanisms and their implementation.

The complexity of this subsystem is determined by the fact that it is in this subsystem that the bulk of information processing is performed, while the main resources for accessing information of system subscribers are concentrated in it - subscribers directly have authorized access to both information and the functions of its processing. That is why the basis of this subsystem is a system for controlling access to information and its processing functions.

The basic mechanism for implementing authorized access to information and its processing functions is the mechanism for protecting information resources from unauthorized actions, the main components of which are:

· organizational and technical means of controlling access to system objects, information and functions for its processing;

· registration and accounting system for the operation of the system and system subscribers;

· integrity assurance subsystem;

· cryptographic subsystem.

The basis for the implementation of the noted protection is the architectural construction of the information component of the ITS - the creation of logically and informationally separated objects of the information component of the ITS (data banks, information and reference complexes, situation centers). This will make it possible to implement cryptographically independent isolated objects operating using client-server technology and not providing direct access to information storage and processing functions - all processing is carried out at the authorized request of users based on the powers granted to them.

For the authorized provision of information resources to subscribers, the following methods and mechanisms are used:

· information security labels;

· identification and authentication of subscribers and system equipment;

· cryptographic protection of information during storage;

· cryptographic control of information integrity during storage.

When implementing a security subsystem in the telecommunications component of an ITS, it is necessary to take into account the availability of communication channels in both controlled and uncontrolled territories.

A justified way to protect information in communication channels is cryptographic protection of information in communication channels in an uncontrolled territory in combination with organizational and technical means of protecting information in communication channels in a controlled territory, with the prospect of transition to cryptographic information protection in all ITS communication channels, including using VPN technology methods. A resource for protecting information in the telecommunications subsystem (taking into account the presence of violators with legal access to telecommunications resources) is the delimitation of access to telecommunications resources with registration of information flows and subscriber operating regulations.

A typical solution for protecting information in communication channels is the use of subscriber and line protection loops in combination with algorithmic and technical means of protection, providing (both directly and indirectly) the following protection mechanisms:

· protection against information leakage into communication channels and technical channels;

· control of the safety of information during transmission via communication channels;

· protection from possible attacks by an intruder via communication channels;

· identification and authentication of subscribers;

· control access to system resources.

The security subsystem for internetwork exchange in ITS is based on the following security mechanisms:

· access control to internetwork resources (firewalling);

· identification and authentication of subscribers (including cryptographic authentication methods);

· identification and authentication of information;

· cryptographic protection of information in communication channels in uncontrolled territory, and in the future - in all communication channels;

· cryptographic isolation of interacting systems.

Of great importance in the subsystem under consideration is the implementation of virtual private network (VPN) technology, the properties of which largely solve the issues of both protecting information in communication channels and countering attacks by intruders from communication channels.

· one of the functions of ITS is making decisions on the management of both individual departments and enterprises, and the state as a whole, based on analytical processing of information;

· the existence of violators among subscribers interacting with ITS systems cannot be ruled out.

The subsystem for identifying and countering the active actions of an intruder is implemented on two main components: hardware and software for identifying and countering possible attacks by intruders via communication channels and the architecture of a secure network.

The first component - the component for identifying possible attacks, is intended for protection in those ITS subsystems in which the intruder's actions in terms of attacks on information resources and ITS equipment are fundamentally possible, the second component is intended to eliminate such actions or significantly complicate them.

The main means of the second component are hardware and software that ensure the implementation of protection methods in accordance with virtual private network (VPN) technology, both during the interaction of various ITS objects in accordance with their structure, and within individual objects and subnets based on firewalls or firewalls with built-in cryptographic protection.

We emphasize that the most effective counteraction to possible attacks is provided by cryptographic means of a linear protection loop and an internetwork cryptographic gateway for external intruders and means of controlling access to information resources for legal users belonging to the category of intruder.

The subsystem for identifying and countering possible hardware and software defects is implemented by a set of organizational and technical measures during the manufacture and operation of ITS equipment, including the following main activities:

· special inspection of foreign-made equipment and components;

· software standardization;

· checking the properties of the element base that affect the effectiveness of the protection system;

· checking software integrity using cryptographic algorithms.

Along with other tasks, the issue of countering possible hardware and software bookmarks is also provided by other means of protection:

· linear cryptographic protection circuit, providing protection against the activation of possible software bookmarks via communication channels;

· archiving of information;

· redundancy (hardware duplication).

By means of ITS at various system objects, OGV users can be provided with various services for information transfer and information services, including:

· secure document flow subsystem;

· certification centers;

· secure subsystem for transmitting telephone information, data and organizing video conferences;

· a secure subsystem of official information, including the creation and maintenance of official websites of leaders at the federal and regional levels.

Note that the secure document flow subsystem is tightly connected with certification centers that ensure the implementation of the digital signature mechanism.

Let us consider in more detail the integration of information security tools into the electronic document management system, into the telephone information transmission subsystem, the official information subsystem and the official website of managers at various levels.

The basic mechanism for protecting information in an electronic document management system is a digital electronic signature, which ensures identification and authentication of documents and subscribers, as well as control of their integrity.

Since the features of the ITS document flow system are determined by the presence of information exchange between various objects and departments (including possible information exchange between secure and unprotected systems), as well as the use of various document processing technologies in different departments, the implementation of secure document flow, taking into account the stated factors, requires the following activities:

· unification of document formats in various departments;

· coordination of security policies in various departments.

Of course, the noted requirements can be partially solved by using gateways between interacting systems.

Certification centers are essentially a distributed database that ensures the implementation of a digital signature in a document flow system. Unauthorized access to the information resources of this database completely destroys the security properties of electronic document management. This leads to the main features of the information security system at certification centers:

· management of access to database resources of certification centers (protection from unauthorized access to resources);

· ensuring stable operation of certification centers in conditions of possible failures and failures, emergency situations (protection against destruction of database information).

The implementation of these mechanisms can be carried out in two stages: at the first stage, protection mechanisms are implemented using organizational and technical protection measures and security measures, including the use of a domestic certified operating system, and at the second stage, cryptographic protection methods are integrated into hardware and software during storage and information processing at certification centers.

Features of protecting various types of traffic transmitted to the ITS (telephone traffic, data and video conferencing traffic) can be divided into two classes:

· features of the protection of subscriber equipment, which are determined by the need to protect information of various types, including simultaneously (video information and speech, and, possibly, data), as well as the need to protect information of various types from leakage into technical channels.

· features of the protection of equipment of a certain type of information transmission system, which are determined by the need to protect against unauthorized access to telephone services, data transmission, conference calls and its resources.

For these classes, the basic protection mechanisms are:

· technical means of protecting information from leakage into technical channels, implemented by standard means;

· access control to resources that support the organization of various types of communications, which is based on the identification and authentication of possible connections of various users and equipment to communications equipment.

A feature of the secure subsystem of official information is the presence of information flows in two directions - from ITS to external systems, including individual citizens of the country, as well as from external systems to ITS (information exchange with unprotected objects).

Based on information received from external systems, decisions are developed in the interests of both individual organizations, departments and regions, and the state as a whole, and the implementation of the decisions made also at all levels of government depends on the information received by external systems.

Therefore, in the first case, the main requirements for the functioning of the system from the point of view of its security are the integrity of the information provided, the efficiency of providing information, including its updating, the reliability of the source of information, and control of the delivery of information to the recipient.

In the second case - the reliability of the information provided, the reliability of the source of information, the efficiency of delivering information, as well as control of delivering information to the recipient. Basically, the listed requirements are provided by standard security mechanisms (cryptographic methods for monitoring the integrity of information, identification and authentication of subscribers and information).

A distinctive feature characteristic of this subsystem is the need to control the reliability of information coming from external systems and which is the source material for making decisions, including in the interests of the state. This problem is solved using analytical methods for monitoring the reliability of information, ensuring the stability of the solutions developed in the face of the receipt of unreliable information, and organizational and technical measures that ensure confirmation of incoming information.

The main goals of the information security system on the website of federal and regional leaders are to prevent information from entering the website that is not intended for this purpose, as well as to ensure the integrity of the information presented on the website.

The basic security mechanism implemented on the site must ensure control of access to the site by the internal system that provides information to the site, as well as control of access by external systems to the site’s resources.

The implementation of protection is based on the creation of a “demilitarized” zone based on firewalls (gateways), providing:

Filtering information in the direction from the internal system to the site with control of access to the site from the internal system (identification and authentication of the source of information) and filtering information using security labels;

Monitoring the integrity of information resources on the site and ensuring stable operation of the site in the face of possible information distortions;

control of access from external systems to site resources;

filtering requests coming to the site from external systems.

One of the most important issues when solving problems of ensuring information security is improving the regulatory framework regarding information security.

The need to improve the regulatory framework is determined by two main factors - the presence of information exchange between various departments, the presence of a large number of types and types of information circulating in the ITS.

In terms of ensuring information security in ITS, the regulatory framework must be improved in the following areas:

· creation of uniform requirements for ensuring information security and, on their basis, a unified security concept, ensuring the possibility of harmonizing security policies in various departments and ITS as a whole, including different periods of operation;

· creation of a unified standard for documentary information, ensuring the implementation of unified security labels and reducing the cost of transmitting documents during interdepartmental interaction;

· creation of provisions for interdepartmental interaction that ensure constant monitoring of information security during interdepartmental interaction.

Conclusion

In this course work the following principles were considered:

· ITS architecture and basic information processing technologies in ITS should be created taking into account the evolutionary transition to domestically developed means;

· automated workstations of ITS information security systems must be created on a domestically produced hardware and software platform (domestic assembled computer, domestic operating system, domestic software);

· ITS architecture and basic information processing technologies in ITS should be created taking into account the possibility of using existing hardware and software security tools at the first stage with their subsequent replacement with promising information security tools.

Fulfillment of these requirements will ensure the continuity and specified efficiency of information protection during the transition period from the use of information processing technologies in ITS in combination with information security technologies to the use of secure information processing technologies in ITS.

Bibliography

1. Konstantin Kuzovkin. Remote access to information resources. Authentication. // Director of information service - 2003 - No. 9.

2. Konstantin Kuzovkin. Secure platform for Web applications. // Open systems - 2001 - No. 4.

Alexey Lukatsky. Unknown VPN. // Computer-Press - 2001 - No. 10.

Internet resources: http://www.niia.ru/document/Buk_1, www.i-teco.ru/article37.html.

Creating a secure data transmission channel between distributed enterprise information resources

A. A. Terenin, Ph.D.,

IT and software quality assurance specialist

Deutsche Bank Moscow

Currently, a large enterprise with a network of branches in the country or the world, in order to successfully conduct business, needs to create a single information space and ensure clear coordination of actions between its branches.

To coordinate business processes occurring in various branches, it is necessary to exchange information between them. Data coming from various offices is accumulated for further processing, analysis and storage at some head office. The accumulated information is then used to solve business problems by all branches of the enterprise.

The data exchanged between branches is subject to strict requirements for its reliability and integrity. In addition, trade secret data must be confidential. For full parallel operation of all offices, information exchange must occur online (in real time). In other words, a permanent data transmission channel must be established between the branches of the enterprise and the head office. To ensure the uninterrupted operation of such a channel, there is a requirement to maintain accessibility to each source of information.

We summarize the requirements that data transmission channels between enterprise branches must meet in order to perform the task of ensuring constant communication with high quality:

the data transmission channel must be constant,

data transmitted over such a channel must maintain integrity, reliability and confidentiality.

In addition, the reliable functioning of a permanent communication channel implies that legal users of the system will have access to information sources at any time.

In addition to distributed corporate systems that operate in real time, there are systems that operate offline. Data exchange in such systems does not occur constantly, but at specified periods of time: once a day, once an hour, etc. Data in such systems is accumulated in separate branch databases (DBs), as well as in central databases, and only data from these databases is considered reliable.

But even if information exchange occurs only once a day, it is necessary to establish a secure data transmission channel, which is subject to the same requirements for ensuring reliability, integrity and confidentiality, as well as availability for the duration of the channel’s operation.

The requirement of reliability means ensuring authorized access, authentication of the parties to interaction and ensuring the inadmissibility of refusal of authorship and the fact of data transfer.

More stringent requirements are imposed on systems for ensuring the security of information transactions in a distributed information environment, but this is a topic for a separate article.

How to ensure such protection of the data transmission channel?

It is possible to connect each branch to each branch with a physical data transmission channel (or only all branches to the center) and ensure the impossibility of access to the physical medium for transmitting information signals. Yes, such a solution may be acceptable for implementation within one protected facility, but we are talking about distributed corporate systems, where the distance between interaction objects can be measured in thousands of kilometers. The cost of implementing such a plan is so high that it will never be cost-effective.

Another option: rent existing, already installed communication channels or satellite channels from telecom operators. Such a solution is also expensive, and protecting these channels will require the implementation or installation of special software for each of the interacting parties.

A very common, inexpensive and effective solution is to organize secure communication channels over the Internet.

Nowadays it is difficult to imagine an organization that does not have access to the Internet and does not use the World Wide Web to organize its business processes. In addition, the information technology market is saturated with network equipment and software from different manufacturers with built-in support for information security. There are standards, secure network protocols that form the basis for the created hardware and software products that are used to organize secure interaction in an open information network.

Let's take a closer look at how you can create secure data transmission channels over the Internet.

The problems of secure data transmission over open networks are widely discussed in popular and mass literature:

The World Wide Web is constantly expanding, means for transmitting and processing data are being developed, and equipment for intercepting transmitted data and accessing confidential information is becoming more and more advanced. Currently, the problem of ensuring the protection of information from its unauthorized copying, destruction or modification during storage, processing and transmission via communication channels is becoming increasingly urgent.

The protection of information when transmitted over open communication channels using asymmetric encryption is discussed in, and the problems and ways to solve them when using an electronic digital signature are discussed in.

This article discusses in detail methods for ensuring information security when transmitting secret data over open communication channels.

To protect information transmitted over public communication channels, many security measures are used: data is encrypted, packets are provided with additional control information, and a data exchange protocol with a high degree of security is used.

Before deciding how to protect transmitted data, it is necessary to clearly outline the range of possible vulnerabilities, list methods of intercepting, distorting or destroying data, and methods of connecting to communication channels. Answer questions about what goals attackers are pursuing and how they can use existing vulnerabilities to implement their plans.

Additional requirements for the implemented protective data transmission channel include:

identification and authentication of interacting parties;

procedure for protecting against substitution of one of the parties (use of public key cryptographic algorithms);

control over the integrity of transmitted data, the route of information transmission and the level of protection of the communication channel;

configuring and checking the quality of the communication channel;

compression of transmitted information;

detection and correction of errors when transmitting data over communication channels;

audit and event registration;

automatic restoration of functionality.

Let's build a model of the intruder and a model of the protected object (Fig. 1).

Connection establishment algorithm

To implement a secure data transmission channel, a client-server interaction model is used.

Two sides are considered: the server and the client - a workstation that wants to establish a connection with the server for further work with it.

Initially, there are only two keys: the public and private keys of the server ( OKS And ZKS), and the server's public key is known to everyone and is transmitted to the client when he accesses the server. The server's private key is stored in the strictest secrecy on the server.

The connection initializer is the client; he gains access to the server through any global network with which this server works, most often through the Internet.

The main task when initializing a connection is to establish a data exchange channel between two interacting parties, prevent the possibility of forgery and prevent the situation of user substitution, when a connection is established with one user, and then another participant in the system connects to one of the sides of the channel and begins to appropriate messages intended for a legitimate user. user, or transmit messages on someone else's behalf.

It is necessary to provide for the possibility of an attacker connecting at any time and repeating the “handshake” procedure at certain time intervals, the duration of which must be set to the minimum permissible.

Based on the assumption that ZKS And OKS have already been created, and OKS everyone knows and ZKS– only to the server, we get the following algorithm:

1. The client sends a connection request to the server.

2. The server starts the application, transmitting to the requesting station some special message for the pre-installed client application, in which the server's public key is hardcoded.

3. The client generates its keys (public and private) to work with the server ( OKC And ZKK).

4. The client generates a session key ( KS) (symmetric message encryption key).

5. The client sends the following components to the server:

client public key ( OKC);

session key;

random message (let's call it X), encrypted with the server's public key using the algorithm RSA.

6. The server processes the received message and sends a message in response X, encrypted with the session key (symmetric encryption) + encrypted with the client’s public key (asymmetric encryption, for example algorithm RSA) + signed by the server's private key ( RSA, DSA, GOST) (that is, if on the client side after decryption we receive X again, then this means that:

the message came from the server (signature – ZKS);

the server accepted our OKC(and encrypted with our key);

server accepted KS(encrypted the message with this key).

7. The client receives this message, verifies the signature and decrypts the received text. If, as a result of performing all the reverse actions, we receive a message completely identical to the message sent to the server X, then it is considered that the secure data exchange channel is installed correctly and is fully ready to operate and perform its functions.

8. Subsequently, both parties begin exchanging messages, which are signed with the sender’s private keys and encrypted with the session key.

The diagram of the connection establishment algorithm is shown in Fig. 2.

Algorithm for preparing a message for sending to a secure channel

The formulation of the problem is as follows: the input of the algorithm is the original (open) text, and at the output, through cryptographic transformations, we obtain a closed and signed file. The main task assigned to this algorithm is to ensure secure text transmission and provide protection in an unprotected channel.

It is also necessary to introduce the ability to prevent information disclosure when a message is intercepted by an attacker. The network is open; any user on this network can intercept any message sent over a data link. But thanks to the protection inherent in this algorithm, the data obtained by the attacker will be completely useless to him.

Naturally, it is necessary to provide for the option of opening by exhaustive search, but then it is necessary to take into account the time spent on opening, which is calculated in a known way, and use the appropriate key lengths that guarantee non-disclosure of the information they cover for a given time.

There is also a possibility that at the other end of the channel (on the receiving side) there was an attacker who replaced the legal representative. Thanks to this algorithm, a message that easily falls into the hands of such an attacker will also be “unreadable”, since the spoofer does not know the public and private keys of the party he has spoofed, as well as the session key.

The algorithm can be implemented as follows (Fig. 3):

the source text is compressed using the ZIP algorithm;

parallel to this process, the source text is signed with the recipient’s public key;

the compressed text is encrypted with a symmetric session key, this key is also on the receiving side;

a digital signature is added to the encrypted and compressed text, uniquely identifying the sender;

the message is ready to be sent and can be transmitted over the communication channel.

Algorithm for processing a message when received from a secure channel

The input of the algorithm is encrypted, compressed and signed text, which we receive via a communication channel. The task of the algorithm is to obtain, using reverse cryptographic transformations, the original plaintext, verifying the authenticity of the message and its authorship.

Since the main task of the system is to create a secure channel on unsecured communication lines, each message undergoes strong changes and carries with it accompanying control and management information. The process of reversing the original text also requires quite a long conversion time and uses modern cryptographic algorithms that involve operations on very large numbers.

If you want to ensure maximum protection for the passage of a message over a secure channel, you have to resort to rather time-consuming and resource-intensive operations. While we gain in security, we lose in the processing speed of forwarded messages.

In addition, it is necessary to take into account the time and machine costs for maintaining the reliability of communication (verification by the parties of each other) and for the exchange of control and management information.

Algorithm for processing a message when receiving from a secure channel (Fig. 4):

a digital signature is extracted from the received encrypted, compressed and signed message;

text without a digital signature is decrypted with the session key;

the decoded text undergoes an unzipping procedure using, for example, the ZIP algorithm;

the text obtained as a result of the two previous operations is used to verify the digital signature of the message;

At the output of the algorithm we have the original open message and the result of the signature verification.

Message signature algorithm

Let's take a closer look at the message signing algorithm. We will proceed from the assumption that all public and private keys of both parties exchanging data have already been generated and the private keys are stored with their immediate owners, and the public keys are sent to each other.

Since the source text can have an unlimited and each time non-constant size, and the digital signature algorithm requires a block of data of a certain constant length for its operation, the hash function value from this text will be used to convert the entire text into its display of a predetermined length. As a result, we get a text display due to the main property of the hash function: it is one-way, and it will not be possible to restore the original text from the resulting display. It is algorithmically impossible to select any text whose hash function value would coincide with the previously found one. This does not allow an attacker to easily replace the message, since the value of its hash function will immediately change, and the verified signature will not match the standard.

To find the hash function value, you can use well-known hashing algorithms ( SHA, MD4, MD5, GOST etc.), which allow you to obtain a data block of a fixed length at the output. It is with this block that the digital signature algorithm will work. Algorithms can be used as an electronic digital signature algorithm DSA, RSA, El Gamal and etc.

Let us describe the message signature algorithm point by point (Fig. 5):

the input of the general algorithm is a source text of any length;

the hash function value for the given text is calculated;

EDS;

using the received data, the value is calculated EDS all text;

At the output of the algorithm, we have a digital signature of the message, which is then sent to be attached to the packet of information sent to the data exchange channel.

Signature verification algorithm

The algorithm receives two components as input: the original text of the message and its digital signature. Moreover, the source text can have an unlimited and each time variable size, but the digital signature always has a fixed length. This algorithm finds the hash function of the text, calculates the digital signature and compares it with the information received as input.

At the output of the algorithm we have the result of checking the digital signature, which can only have two values: “the signature matches the original, the text is genuine” or “the signature of the text is incorrect, the integrity, authenticity or authorship of the message is suspicious.” The output value of this algorithm can then be used further in the secure channel support system.

Let us describe the algorithm for checking a message signature point by point (Fig. 6):

the input of the general algorithm is a source text of any length and a digital signature of this text of a fixed length;

the hash function value from the given text is calculated;

the resulting text display of a fixed length enters the next algorithmic processing block;

the digital signature that came as the input of the general algorithm is sent to the same block;

also the input of this block (calculation of the digital signature) receives a secret (private) key, which is used to find EDS;

using the received data, the value of the electronic digital signature of the entire text is calculated;

we received a digital signature of the message, comparing it with EDS, received as the input of the general algorithm, we can draw conclusions about the reliability of the text;

At the output of the algorithm we have the result of checking the digital signature.

Possible attacks on the proposed scheme for implementing a secure communication channel

Let's look at the most common examples of possible attacks on a secure data transmission channel.

First, you need to decide what and who you can trust, because if you don’t trust anyone or anything, then there is no point in writing such programs to support data exchange over the global network.

We trust ourselves, as well as the software installed on the workstation.

When we use a browser (Internet Explorer or Netscape Navigator) to communicate with a server, we trust that browser and trust it to verify the certificates of the sites we visit.

After checking the signature on the applet you can trust OKS, which is embedded in data or programs (applets) downloaded from the server.

Possessing OKS, which we trust, we can begin further work with the server.

If the system is built using client applications, then you must trust the installed client software. Then, using a chain similar to the one above, we can trust the server with which the connection is established.

Possible attacks.

1. Upon transfer OKS. It is, in principle, accessible to everyone, so it will not be difficult for an attacker to intercept it. Possessing OKS, theoretically it is possible to calculate ZKS. It is necessary to use cryptographic keys of sufficient length to maintain confidentiality for a given time.

2. After transfer from the server OKS and before the client sends his OKC And KS. If during their generation ( OKC, ZKK And KS) a weak random number generator is used, you can try to predict all three specified parameters or any one of them.

To repel this attack, it is necessary to generate random numbers that meet a number of requirements. It is impossible, for example, to use a timer to generate random numbers, since an attacker, having intercepted the first message ( OKS from the server), can set the time of sending a packet with an accuracy of seconds. If the timer fires every millisecond, then a complete search of only 60,000 values ​​(60 s _ 1000 ms) is required to open it.

To generate random numbers, it is necessary to use parameters that are not available to the attacker (his computer), such as the process number or other system parameters (such as the descriptor identification number).

3. When transmitting a packet containing OKC, KS, X, encrypted OKS. To reveal intercepted information, you must have ZKS. This attack boils down to the attack discussed above (selection ZKS). The private information itself transmitted to the server is useless to an attacker.

4. When transmitting some test message from the server to the client X, encrypted KS And OKC and signed ZKS. To decrypt an intercepted message, you need to know and OKC, And KS, which will be known if one of the above attacks is implemented after the enemy has become aware ZKS.

But decrypting a test message is not so scary; a much greater danger is the possibility of forging the transmitted message, when an attacker can impersonate the server. For this he needs to know ZKS to correctly sign the package and all the keys KS And OKC, like the message itself X in order to correctly compose the forged package.

If any of these points are violated, the system is considered compromised and unable to further ensure the secure operation of the client.

So, we looked at the attacks that are possible at the stage of implementing the “handshake” procedure (HandShake). Let us describe attacks that can be carried out during data transmission over our channel.

When intercepting information, an attacker can read the plaintext only if he knows KS. An attacker can predict or guess it by completely trying out all its possible values. Even if the adversary knows the message (that is, he knows exactly what the plaintext looks like corresponding to the code he intercepted), he will not be able to unambiguously determine the encryption key because the text has been subjected to a compression algorithm.

It is also impossible to use a "probable word pull" attack, since any word will look different in each message. Because archiving involves shuffling information, similar to what happens when calculating a hash value, previous information influences what the next block of data will look like.

From what has been described it follows that in any case, an attacker can only use an attack based on an exhaustive search of all possible key values. To increase resistance to this type of attack, it is necessary to expand the range of values KS. When using a 1024-bit key, the range of possible values ​​increases to 2 1024 .

To write or replace messages transmitted over a communication channel, an attacker needs to know the private keys of both parties participating in the exchange or know one of the two private keys ( ZK). But in this case, he will be able to forge messages only in one direction, depending on whose ZK he knows. He can act as a sender.

When trying to spoof any of the parties, that is, when trying to impersonate a legal participant in the exchange after establishing a communication session, he needs to know KS And ZK(see cases discussed earlier). If not KS, nor ZK the person in whose place he wants to connect to the communication channel is unknown to the attacker, then the system will immediately know about it, and further work with the compromised source will stop.

At the very beginning of work, when connecting to a server, a trivial attack is possible: spoofing the DNS server. It is not possible to protect yourself from it. The solution to this problem is the responsibility of administrators of DNS servers managed by Internet providers. The only thing that can save you is the procedure already described above for checking the site’s certificate with a browser, confirming that the connection was made to the desired server.

Conclusion

The article discussed methods for constructing a secure data transmission channel to ensure interaction between distributed corporate computing systems.

A protocol has been developed for establishing and maintaining a secure connection. Algorithms for ensuring data transmission protection are proposed. Possible vulnerabilities of the developed interaction scheme are analyzed.

A similar technology for organizing secure connections is organized by the SSL network communication protocol. In addition, virtual private networks (VPN) are built based on the proposed principles.

LITERATURE

1. Medvedovsky I. D., Semyanov P. V., Platonov V. V. Attack on the Internet. - St. Petersburg: Publishing house "DMK" 1999. - 336 p.

2. Karve A. Public key infrastructure. LAN/Journal of Network Solutions (Russian edition), 8, 1997.

3. Melnikov Yu. N. Electronic digital signature. Protection capabilities. Confidential No. 4 (6), 1995, p. 35–47.

4. Terenin A. A., Melnikov Yu. N. Creation of a secure channel in the network. Materials of the seminar “Information Security - South of Russia”, Taganrog, June 28–30, 2000.

5. Terenin A. A. Development of algorithms for creating a secure channel in an open network. Automation and modern technologies. – Publishing house “Machine Building”, No. 6, 2001, p. 5–12.

6. Terenin A. A. Analysis of possible attacks on a secure channel in an open network created by software. Materials of the XXII Conference of Young Scientists of the Faculty of Mechanics and Mathematics of Moscow State University, Moscow,April 17–22, 2000.