RU2812304C1 - Method for ensuring integrity of electronic document - Google Patents

Abstract

FIELD: computer engineering.

SUBSTANCE: at the time of generation of an electronic document, an information block is formed, which is an electronic document created by combining a subset of content and a subset of static metadata records, on which cryptographic transformation operations are simultaneously performed. Integrity of an electronic document is monitored on the basis of content data and calculated values of its signatures of metadata records and their signatures of common signatures of root signatures of metadata records, common root signatures of an electronic document, as well as root signatures of the life cycle of the electronic document that have undergone the storage procedure and are subject to integrity control.

EFFECT: improved level of security of electronic documents due to the ability to control their integrity, as well as to detect and localize content and metadata records that have undergone unauthorized modification by authorized users.

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Description

Field of technology to which the invention relates The invention relates to information technology and can be used to ensure the integrative integrity of electronic documents processed in automated information systems for electronic document management (AIS ED), under conditions of intentional and unintentional influences of authorized users (insiders).

State of the art

The term "electronic document" refers to documented information created, received and maintained by an organization or individual as evidence and an asset to support a legal obligation or business transaction. The composition of an electronic document is defined as a set of content and metadata that describe the context, content and structure of documents, and Metadata must be managed, like the electronic document itself, since they must be protected from loss or unauthorized deletion and stored or destroyed in an established manner. In this case, the protection of metadata is reduced

to the distribution of access rights and compliance with the relevant rules, excluding cryptographic means of protection in the form of electronic signatures that provide the content of an electronic document (GOST R ISO 15489-1-2019 System of standards for information, library and publishing. Document management. Part 1. Concepts and principles ).

Thus, with the current structure of an electronic document, its integrity has a functional dependence on two components (content and metadata), which have only a logical connection with each other, which, under the conditions of intentional or unintentional destructive influences of authorized users (insiders), will not ensure the integrity of the electronic document in full or partial loss of one of the components.

Below, to reveal the essence of the invention, a brief description of existing technical solutions for data integrity monitoring is provided.

a) Description of analogues

There is a known method for monitoring the integrity of data records based on the “write once” method (Atsushi Harada, Masakatsu Nishigaki, Masakazu Soga, Akio Takubo, Itsukazu Nakamura. A Write-Once Data Management System, ICITA 2002. - Shizuoka University, Japan, 2002, [Electronic resource] - http://www.icita.org/previous/icita2002/ICITA2002/kptdata/116-21/index.htm), which uses various combinations of user electronic signatures to protect (integrity control) records from authorized users.

The disadvantage of this method is the lack of functionality for establishing additional parameters for entering key data of various users and the order of their application (secret for the users themselves or for various groups of users, the composition of which is unknown to the users themselves), allowing to ensure an appropriate level of security for data records in the file.

A widely known method for authenticating messages is NMAC (hash-based message authentication), the essence of which is to use a cryptographic hash function in combination with one secret key and NMAC with two secret keys (M. Bellare, R. Canetti and N. Krawczyk, Keying Hash Functions for Message Authentication, Advances in Cryptology Proceedings of CRYPTO 1996, pp.1-15, Springer-Verlag, [Electronic resource] - http://dblp.uni-trier.de/db/conf/crypto/crypto96, [Electronic resource] - http://daily.sec.ru/2012/07/16/print-Algoritmi-auntentifikatsii-soobsheniy-HMAC-i-NMAC.html).

Message integrity control in the NMAC message authentication method is that the sender of the message M, using two secret (external) keys k ₁ and k _2, calculates the message authentication code according to the rule: H=hash(k ₂ ||hash(M||k ₁ )), where || - concatenation symbol, hash - calculation function in the hash code generation block. A message with an authenticity code (M, N) is received by the recipient via a message transmission channel located in a non-trusted environment. The trusting party (message recipient) checks the compliance of the received authentication code H* to control the integrity and authentication of the M* message.

The disadvantage of this method is the low level of data security from attacks by authorized users (insiders) (there must be two parties who trust each other, confidentiality of secret keys).

There is a well-known technical solution “System for monitoring the integrity of logs of continuously maintained data records” according to RF patent No. 2637486, published on December 4, 2017, which allows for monitoring the integrity of logs of continuously maintained data records, through the use of both keyless and key hash functions used to ensure required level of data security.

The disadvantages of this solution are:

- inability to localize data record numbers with signs of integrity violations when authorized users implement destructive influences on AIS ED;

- relatively high complexity of the operation of monitoring the integrity of data records, since its implementation requires the use of the entire set of keys V _U at all stages of data conversion, which represents a significant limitation and technical difficulty for using this method, especially in mobile applications.

b) Description of the closest analogue (prototype)

The closest in its technical essence to the claimed invention (prototype) is the “Method for cryptographic recursive 2-D control of the integrity of metadata of electronic document files” according to RF patent No. 2726930, published on July 16, 2020, which allows increasing the level of security of metadata of electronic documents processed by AIS ED, with the ability to control their integrity. An essential feature that distinguishes the prototype from known analogues is the implementation of functionality to detect and localize numbers of unauthorized modified metadata records in the event of a violation of their integrity by authorized users (insiders).

The disadvantage of this known method is the lack of functionality to ensure the integrative integrity of an electronic document, achieved through the physical coherence of the content and metadata included in its composition, which, under conditions of intentional or unintentional destructive influences of authorized users (insiders), will not ensure the integrity of the electronic document during the life cycle in case of complete or partial loss of one of its components.

Disclosure of the invention (its essence)

a) the technical result to achieve which the invention is aimed

The purpose of the claimed invention is to develop a method for ensuring the integrative integrity of an electronic document based on the application of cryptographic hash functions to its components (content and metadata), the results of which are calculated according to the type of binary Merkle tree, which makes it possible to increase the level of security of electronic documents processed by AIS ED, with the ability to control their integrity, as well as the detection and localization of content and metadata records that have undergone unauthorized modification by authorized users (insiders).

b) a set of essential features

This goal is achieved by the fact that in the known method of cryptographic recursive 2-D control of the integrity of metadata of electronic document files, the integrity of metadata when performing the operation of writing and editing electronic document files is controlled due to the fact that at times t _i records m _i1 , m _i2 are formed , m _i3 , …, m _in metadata on which cryptographic transformation operations are performed on the keys contained in the second part of the subset sets of keys, and the set of keys V _U is divided into two subsets And , with each part of the subsets containing keys And , where q=1,2 is the membership of the keys in the corresponding part of the subsets, for all U=1,…,ς is the number of the key in the corresponding part of the subsets. Moreover, as a cryptographic transformation either a key hash function is used, and or an electronic signature, while The obtained results h _i1 , h _i2 , h _i3 , ..., h _{in of} the calculated signatures are stored in the memory of the data processing system for subsequent monitoring of the integrity of the metadata records of the electronic document.

A comparative analysis of the claimed solution with the prototype shows that the proposed method differs from the known one in that at the moment of formation t ₀ of the electronic document, an information block is formed in the memory of the data processing system , which is an electronic document created by combining a subset of content and subsets of static metadata records , on which cryptographic transformation operations are simultaneously performed:

Double concatenation operations are performed on the calculated signature values h ₀₁ , h ₀₂ , h ₀₃ , …, h _0n of static metadata records:

over the results of which cryptographic transformation operations are performed on the keys

After which, over the newly calculated signatures, the operations of concatenation and cryptographic transformation on the keys repeat:

the result of which is the formation of a root signature Σh ₀ of static metadata records.

Then the concatenation and cryptographic transformation operations on the keys is performed on the value of the signature H ₀ of the content and the root signature Σh ₀ of static metadata records in order to obtain a common root signature of the electronic document created at time t ₀ :

After the operations performed, the electronic document is entered into the system, and during its life cycle t ₁ , t ₂ , ..., t _k , when recording and editing, the above operations are performed on it.

In this case, the common root signature S ₁ of the electronic document, calculated at time t ₁ , is concatenated with the common root signature S ₀ of the electronic document, calculated at time t ₀ , with simultaneous cryptographic transformation on the keys thereby forming the root signature of the life cycle S ₀₁ of the electronic document:

As the electronic document changes, operations are repeated in a similar order in accordance with the time points t ₂ , t ₃ , ..., t _k of its life cycle.

Content and calculated values of its signatures _Hi , metadata records m _i1 , m _i2 , m _i3 , …, m _in and their signatures h _i1 , h _i2 , h _i3 , …, h _in , general signatures root signatures Σh _i of metadata records, common root signatures S _{i of} an electronic document, as well as root signatures S _{jn of} the life cycle of an electronic document are stored in the memory of the data processing system and are used to verify the integrity of the electronic document at time points of its life cycle t ₀ , t ₁ , t ₂ , …, t _k .

The integrity of an electronic document is monitored by retrieving content from the memory of the data processing system and the calculated values of its signatures , metadata records and their signatures common signatures metadata records, root signatures metadata records, common root signatures electronic document, as well as root signatures life cycle of an electronic document that has undergone a storage procedure and is subject to integrity control. Repeated cryptographic transformation operations are then performed on the extracted content and metadata records the result of which is the calculation of signatures:

Next, the resulting signatures are compared in pairs with previously saved signatures:

The conclusion that there is no violation of the integrity of the electronic document is made when the equalities are satisfied:

otherwise, a conclusion is made about an integrity violation for the corresponding signature numbers of the electronic document.

c) cause-and-effect relationship between characteristics and technical result

Thanks to a new set of essential features, the method implements the ability to:

- ensuring integrability and monitoring the integrity of the electronic document;

- increasing the level of security of electronic documents processed by AIS ED, due to the coherence of their components (content and metadata), under the conditions of intentional and unintentional influences of authorized users (insiders);

- reducing the complexity of calculating verification activities by constructing a tree structure of electronic document metadata.

Thus, the proposed technical solution allows us to ensure the required level of security of electronic documents processed in the AIS ED.

The analysis of the level of technology made it possible to establish that there are no analogues characterized by a set of features identical to all the features of the claimed method, which indicates that the claimed method complies with the patentability condition of “novelty”.

The results of a search for known solutions in this and related fields of technology in order to identify features that coincide with the features of the claimed method that are distinctive from the prototype, showed that they do not follow explicitly from the prior art. The prior art also does not reveal the knowledge of distinctive essential features that determine the same technical result that was achieved in the claimed method. Therefore, the claimed invention meets the patentability requirement of “inventive step”.

Brief description of drawings

The claimed method is illustrated by drawings, which show:

fig. 1 - structure of preparation and processing of content and metadata records when implementing a method for ensuring the integrative integrity of an electronic document;

fig. 2 - diagram of the formation of an electronic document when implementing the proposed technical solution;

fig. 3 - diagram of the formation of the root signature Σh _i , records

static metadata of an electronic document;

fig. 4 - diagram explaining the procedure for ensuring integrability and monitoring the integrity of an electronic document;

fig. 5 - electronic document file “Manager’s Order.doc”, generated by the executor at time t ₀ ;

Fig.6 - file of the electronic document “Manager’s Order.doc”, edited by the responsible official at time t ₁ ;

fig. 7 - file of the electronic document “Manager’s Order.doc”, edited by the executor at time t ₂ ;

fig. 8 - file of the electronic document “Manager’s Order.doc”, edited by the responsible official at time t _k ;

fig. 9 - unauthorized modified file of the electronic document “Manager’s Order.doc” at time t _k ;

table 1 - presentation of metadata of the electronic document file “Manager’s Order.doc” in the process of editing by authorized users;

table 2 - representation of metadata records of the electronic document file “Manager’s Order.doc” in the hexadecimal number system HEX (ANSI code).

Implementation of the claimed method

The method for ensuring the integrative integrity of an electronic document is carried out as follows (Fig. 1).

The set of keys V _U is divided into two subsets Moreover, each part of the subsets contains keys where q=1,2 - belonging of the keys to the corresponding part of the subsets, for all U=1,...,ς - number of the key in the corresponding part of the subsets.

In the considered implementation of this method, the keys are the keys of the performer (author) of the electronic document, the keys - internal system keys. At the moment of formation t ₀ of the electronic document, an information block is formed in the memory of the data processing system , which is an electronic document created by combining a subset of content and subsets of static metadata records (Fig.2), on which cryptographic transformation operations are simultaneously performed (Fig.1):

Double concatenation operations are performed on the calculated signature values h ₀₁ , h ₀₂ , h ₀₃ , …, h _0n of static metadata records:

over the results of which cryptographic transformation operations are performed on the keys

After which, over the newly calculated signatures, the operations of concatenation and cryptographic transformation on the keys repeat:

the result of which is the formation of a root signature Σh ₀ of static metadata records (Fig. 3).

Then the concatenation and cryptographic transformation operations on the keys is performed on the value of the signature H ₀ of the content and the root signature Σh ₀ of static metadata records in order to obtain a common root signature of the electronic document created at time t ₀ :

After the operations performed, the electronic document is entered into the system, and during its life cycle t ₁ , t ₂ , ..., t _k when executing

recording and editing the operations described above are performed on it (Fig. 1).

In this case, the common root signature S ₁ of the electronic document, calculated at time t ₁ , is concatenated with the common root signature S ₀ of the electronic document, calculated at time t ₀ , with simultaneous cryptographic transformation on the keys thereby forming the root signature of the life cycle S ₀₁ of the electronic document (Fig. 1):

As the electronic document changes, operations are repeated in a similar order in accordance with time points t ₂ , t ₃ , ..., t _k of its life cycle (Fig. 1).

Content and calculated values of its signatures _Hi , metadata records m _i1 , m _i2 , m _i3 , …, m _in and their signatures h _i1 , h _i2 , h _i3 , …, h _in , general signatures metadata records, root signatures Σh ₁ . metadata records, common root signatures S _{i of} an electronic document, as well as root signatures S _in of the life cycle of an electronic document are stored in the memory of the data processing system and are used to verify the integrity of the electronic document at points in its life cycle t ₀ , t ₁ , t ₂ , ... , _tk .

The integrity of an electronic document is monitored by retrieving content from the memory of the data processing system and the calculated values of its signatures , metadata records and their signatures , common signatures metadata records, root signatures metadata records, common root signatures electronic document, as well as root signatures life cycle of an electronic document that has undergone a storage procedure and is subject to integrity control, over which repeated cryptographic transformation operations are performed on the extracted content and metadata records

As a result, the newly calculated signatures are:

are compared in pairs with previously extracted ones:

The conclusion that there is no violation of the integrity of the electronic document is made when the equalities are satisfied:

otherwise, a conclusion is made about an integrity violation for the corresponding signature numbers (Fig. 4).

As a cryptographic transformation either a key hash function is used, and or an electronic signature, while

The correctness and practical feasibility of this method is substantiated by the following examples.

An example of generating an electronic document and monitoring its integrity.

Let “Manager's Order.doc” be an electronic document file (Fig. 5) generated by the executor at time t ₀ (Table 1). In this case, an information block is formed in the memory of the data processing system , which is an electronic document created by combining a subset of content and subsets of static metadata records (Fig.2).

Let us carry out cryptographic transformation of the content of an electronic document in accordance with the claimed method based on the hash function of the md5 algorithm (Fig. 1):

Next, in order to simplify cryptographic transformations, we will encode the letter designations of the metadata records of the electronic document file “Order of the Manager.doc” into an information sequence of characters using the hexadecimal number system HEX (ANSI code) (Table 2).

Let us carry out cryptographic transformations of static metadata records of the electronic document file “Manager’s Order.doc” in accordance with the stated method based on the hash function of the md5 algorithm (Fig. 1):

Over the calculated signature values h ₀₁ , h ₀₂ , h ₀₃ , ..., h _0n of static metadata records, we perform double operations of concatenation and cryptographic transformation:

In order to obtain the value of the root signature Σh ₀ of static metadata records, we repeat the operation of concatenation and cryptographic transformation on the newly calculated signatures (Fig. 3):

Then we perform the operation of concatenation and cryptographic transformation on the value of the signature H ₀ of the content and the root signature Σh ₀ of static metadata records in order to obtain a common root signature of the electronic document created at time t ₀ (Fig. 1):

After the operations are completed, the electronic document is entered into the system.

During the life cycle of an electronic document, it is edited. So, for example, at time t ₁ the responsible person assigned it a date and number (Fig. 6). Let us trace the chain of changes in the content and metadata of the electronic document in accordance with the stated method (Table 1).

Let's carry out a cryptographic transformation of the content of the electronic document edited at time t ₁ (Fig. 1):

Then we will carry out cryptographic transformations of the metadata records of the electronic document edited at time t ₁ (Fig. 1):

Over the calculated values of the signatures h ₁₁ , h ₁₂ , h ₁₃ , ..., h _1n of metadata records, we perform double operations of concatenation and cryptographic transformation:

Let's calculate the root signature Σh ₁ of metadata records of an electronic document edited at time t ₁ (Fig. 3):

Let's calculate the general root signature of an electronic document edited at time t ₁ , for which we perform a concatenation operation on the value of the content signature H ₁ and the root signature Σh ₁ , and a cryptographic transformation (Fig. 1):

Next, in order to obtain the root signature of the life cycle S _0l of an electronic document, we perform a concatenation operation on the common root signatures S ₀ and S ₁ of an electronic document, calculated at the corresponding points in time, and cryptographic transformation (Fig. 1):

Let at time t ₂ the performer decide to expand the text of the electronic document (Fig. 7). Let us trace the chain of changes in the content and metadata of the electronic document in accordance with the stated method (Table 1).

Let's carry out a cryptographic transformation of the content of the electronic document edited at time t ₂ (Fig. 1):

Let us carry out cryptographic transformations of metadata records of an electronic document edited at time t ₂ (Fig. 1):

Over the calculated values of the signatures h ₂₁ , h ₂₂ , h ₂₃ , ..., h _2n of metadata records, we perform double operations of concatenation and cryptographic transformation:

Let's calculate the root signature Σh ₂ of metadata records of an electronic document edited at time t ₂ (Fig. 3):

Let's calculate the general root signature of an electronic document edited at time t ₂ , for which we perform concatenation operations on the value of the content signature H ₂ and the root signature Σh ₂ , and cryptographic transformation (Fig. 1):

In order to obtain the root signature of the life cycle S ₀₁₂ , we perform concatenation operations on the root signature of the life cycle S ₀₁ and the general root signature S ₂ of the electronic document, calculated at time t ₂ , and cryptographic transformation (Fig. 1):

At time t _k the responsible official re-registered the electronic document (Fig. 8). Let us trace the chain of changes in the content and metadata of the electronic document in accordance with the stated method (Table 1).

Let's carry out a cryptographic transformation of the content of the electronic document edited at time t _k (Fig. 1):

Let us carry out cryptographic transformations of metadata records of an electronic document edited at time t _k (Fig. 1):

Over the calculated values of signatures h _k1 , h _k2 , h _k3 , ..., h _kn of metadata records, we perform double operations of concatenation and cryptographic transformation:

Let's calculate the root signature Σh _k of metadata records of an electronic document edited at time t _k (Fig. 3):

Let's calculate the general root signature of an electronic document edited at time _tk , for which we will perform concatenation operations on the value of the content signature _Hk and the root signature Σh _k , and cryptographic transformation (Fig. 1):

In order to obtain the root signature of the life cycle S _012k , we perform concatenation operations on the root signature of the life cycle S ₀₁₂ and the general root signature S _k of the electronic document, calculated at time t _k , and cryptographic transformation (Fig. 1):

The calculated signatures are stored in the memory of the AIS data processing system for the purpose of subsequent monitoring of the integrity of the electronic document file “Manager’s Order.doc”, edited during the entire life cycle t ₀ , t ₁ , t ₂ , ..., t _k .

We will monitor the integrity of the electronic document “Manager’s Order.doc”, edited at time t _k . Why do we calculate the life cycle signature? of this electronic document and compare it with the signature extracted memory of the AIS ED data processing system, which previously underwent a storage procedure (Fig. 4). If the equality is true:

then a conclusion is made that there has been no violation of the integrity of this signature; accordingly, the electronic document “Order of the Manager.doc” has not been subject to unauthorized modification.

An example of unauthorized modification of an electronic document and control of its integrity.

Let's consider a case in which an authorized user (insider) at time t _k managed to unauthorizedly modify the content of the electronic document “Manager's Order.doc” (Fig. 9), and also change the metadata record m _k3 from “July 9, 2021” to "July 10, 2021" (ANSI code: 313020E8FEEBFF203230323120E32E).

By comparing the calculated lifecycle signature electronic document with a reference signature having passed the storage procedure we get:

The obtained result indicates a violation of the integrity of the electronic document “Manager’s Order.doc” during its life cycle t ₀ , t ₁ , t ₂ , …, t _k .

In order to identify the moment of an unauthorized change, let’s compare the life cycle signature electronic document with a reference signature having passed the storage procedure we get:

The result obtained indicates that there was no violation of the electronic document at the corresponding point in time, which gives reason to believe that it was unauthorized changed at time t _k Let's check the common root signature electronic document edited at time t _k , comparing it with the reference common root signature having passed the storage procedure we get:

Thus, we can conclude that there was an unauthorized change in the electronic document at time _tk .

In order to localize the unauthorized change, we will perform a repeated cryptographic transformation of the content of the electronic document that has undergone the storage procedure, edited at time t _k (Fig. 1):

Then we compare the resulting signature content of an electronic document with a reference signature passed the storage procedure:

The result allows us to conclude that there was an unauthorized change in the content of the electronic document being edited at time _tk .

In order to check the integrity of electronic document metadata records, we compare their root signature with reference root signature passed the storage procedure:

The result indicates an unauthorized change in the metadata records of an electronic document edited at time _tk .

In order to localize unauthorized changes to electronic document metadata records, we will compare signatures with reference signatures have undergone the storage procedure:

The obtained result allows us to assert that there was an unauthorized change in metadata records m _k3 , m _km . Let's verify this by comparing the signatures electronic document metadata records with reference signatures have undergone the storage procedure:

The obtained calculations allow us to conclude that as a result of illegitimate actions of an authorized user (insider), the electronic document “Manager’s Order.doc” was unauthorized modified at time _tk , in terms of its content and its metadata records m _k3 .

Thus, the given example showed that the proposed method of ensuring integrability and monitoring the integrity of an electronic document functions correctly, is technically feasible and allows us to solve the problem.

Claims (2)

A method of ensuring the integrative integrity of an electronic document, which consists in the fact that the coherence of the content and metadata of an electronic document when performing recording and editing operations is ensured due to the fact that at times t _i records m _i1 , m _i2 , m _i3 , ..., m _in are formed metadata on which cryptographic transformation operations are performed on the keys contained in the second part of the subset set of keys V _U , and the set of keys V _U is divided into two subsets Moreover, each part of the subsets contains keys And where q=1, 2 - belonging of the keys of the corresponding part of the subsets, for all U=1,...,ς - number of the key in the corresponding part of the subsets, and as a cryptographic transformation either a key hash function is used, and or an electronic signature, while the obtained results h _i1 , h _i2 , h _i3 , ..., h _in signatures are stored in the memory of the data processing system for subsequent monitoring of the integrity of the metadata records of the electronic document, characterized in that at the moment of formation t ₀ of the electronic document an information block is formed in the memory of the data processing system which is an electronic document created by combining a subset of content and subsets of static metadata records on which cryptographic transformation operations are simultaneously performed, and on the keys , A on the keys , as a result of which the values of content signatures H ₀ and static metadata records h _0l , h ₀₂ , h ₀₃ , ..., h _0n are formed, double-places are made over the calculated values of signatures h ₀₁ , h ₀₂ , h ₀₃ , ..., h _0n of static metadata records concatenation and cryptographic transformation operations on the keys , after which the concatenation and cryptographic transformation operations are performed on the newly calculated signatures on the keys are repeated, resulting in the formation of a root signature Σh ₀ of static metadata records, then the operation of concatenation and cryptographic transformation on the keys performed on the value of the content signature H ₀ and the root signature Σh ₀ of static metadata records in order to obtain a common root signature S ₀ of an electronic document created at time t ₀ , after the operations performed, the electronic document is entered into the system, and during its life cycle t ₁ , t ₂ , …, t _k when recording and editing is performed on it similar operations are performed, while the common root signature S ₁ of the electronic document, calculated at time t ₁ , is concatenated with the common root signature S ₀ of the electronic document, calculated at time t ₀ , with simultaneous cryptographic transformation on the keys , thereby forming the root signature of the life cycle electronic document, over which a concatenation operation is performed with the common root signature S ₂ of the electronic document, calculated at time t ₂ , and a cryptographic transformation on the keys , the result is the root lifecycle signature electronic document, after which the above operations are repeated in a similar order, content and the calculated values of its signatures _Hi , metadata records m _i1 , m _i2 , m _i3 , …, m _in and their signatures h _i1 , h _i2 , h _i3 , …, h _in , general signatures h _i1i2 , h _i3in of metadata records, root signatures Σh _i , metadata records, general root signatures S _i of an electronic document, as well as root signatures S _{in of} the life cycle of an electronic document are stored in the memory of the data processing system and are used to verify the integrity of the electronic document at points in its life cycle t ₀ , t _l , t ₂ , …, t _k , the integrity of the electronic document is monitored based on retrieving content from the memory of the data processing system and the calculated values of its signatures metadata records and their signatures common signatures metadata records, root signatures metadata records, common root signatures electronic document, as well as root signatures life cycle of an electronic document that has undergone a storage procedure and is subject to integrity control, repeated cryptographic transformation operations on the extracted content and metadata records , the result of which is the calculation of signatures and subsequent pairwise comparison of the obtained signatures with previously saved ones signatures, the conclusion about the absence of a violation of the integrity of the electronic document is made when the equality otherwise, a conclusion is made about an integrity violation for the corresponding signature numbers of the electronic document.

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