RU2819174C1 - Method of determining source of data packets in telecommunication networks - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to information security in distributed information systems, authentication of sources of messages transmitted in such systems and determination of reliability of message belonging to the source that generated it. It is achieved by using a unique key for encrypting each message, formed from a pseudorandom sequence and controlling the order of arrival of messages based on the results of decrypting the message in the receiver and generation of an authentication code from the decoded messages, which is compared with the authentication code of the received message. Message number in the communication session is taken equal to the number of the key, which gave the correct result when checking the authentication code, and after each successful verification of the authentication code, the subset of keys of this communication session is changed by removing the key with the lowest number from it and adding a key with a number greater than the maximum key number of the subset by one.

EFFECT: high security of transmitted data and resistance to channel errors.

1 cl, 2 dwg

Description

The method relates to the field of information protection in distributed information systems, authentication of sources of messages transmitted in such systems and determination of the authenticity of a message belonging to the source that generated it.

The closest to the proposed invention in terms of the set of essential features are a system and method for registering and authenticating users without passwords (application RU No. 2713604 C1, IPC H04L 29/06, G06F 21/62, G06F 21/30, H04L 9/32, registration date 15.09 .2017, publication date 02/05/2020). This method ensures anonymity of data transfer between the source and receiver of messages by storing authentication codes by a trusted third party. The unique identifiers of the list of digital key codes from which the key must be extracted are used as authentication codes. The disadvantages of this method include the use of a machine-readable storage medium, which leads to the need to use hardware processing, and the data protection system deactivates authentication codes if they are compromised, which leads to the propagation of channel errors.

There is a known method and system for imparting anonymity to a multi-node performance indicator and for managing actions and re-identification of anonymous data (application RU No. 2664406 C2, IPC G06F 17/30, registration date 12/09/2013, publication date 08/17/2018). This method provides anonymity to the data source by using unique attributes to denormalize the data that is transferred to the remote computing resource. A table of unique identifiers is generated to display each unique attribute and transform the data into a normalized form. The disadvantage of this method is the storage of denormalized data from multiple sources on a remote computing resource, which leads to additional time delays.

Systems and methods are known to simplify secure electronic transactions (application RU No. 2740734 C2, IPC G06Q 20/08, registration date 10/12/2016, publication date 01/20/2021). This method ensures the anonymity of the system user's identification data in relation to the issuer's system during a transaction between the payer's system and the payee's system using the issuer's system. The disadvantage of this method is that in the payer’s system the transferred digital token is encrypted using the public key of the issuer’s system in which it is authorized, which leads to the need to transmit identification data over an open communication channel.

The technical task is to increase the security of transmitted data and resistance to channel errors by using a unique key, formed from a pseudo-random sequence, to encrypt each message and control the order of arrival of messages based on the results of decrypting the message at the receiver.

The technical problem is solved by the fact that before the start of a communication session, the source and receiver exchange a secret identifier for the communication session, the source and receiver generate identical pseudo-random sequences based on the secret identifier, the source and receiver select disjoint bit sequences from the generated pseudo-random sequences in the same way, which form a set of cryptographic keys of a given communication session, when transmitting a message, the source encrypts it with a key with a serial number equal to the message number in the communication session and, based on the original contents of the message, generates a message authentication code using cryptographic hashing algorithms, the source transmits the encrypted message along with the authentication code of this message, the receiver stores everything key sets for all active communication sessions, for each communication session at each moment in time, a certain subset of keys is selected from the set of keys, used to decrypt incoming messages, the message received by the receiver is decrypted for each communication session using all the keys of the entire subset of keys for this communication session, During each decryption procedure, the authentication code is checked by comparing the code generated using cryptographic hashing algorithms with the message authentication code received along with the message, the message is considered generated by the source and belonging to a specific communication session, if during decryption the verification of the authentication code was successful, the key number that gave the correct the result when checking the authentication code is accepted as the number of the message received by the receiver during the communication session; after each successful verification of the authentication code, the subset of keys for this communication session is changed by removing the key with the lowest number from it and adding a key with a number one greater than the maximum number subset key.

Figure 1 shows an example of message generation based on a set of cryptographic keys for a given communication session, obtained on the basis of a pseudo-random sequence, and transmitted to the receiver.

Figure 2 shows an example of decrypting an incoming message, with “yes” - the message is considered issued by a source and belonging to a specific communication session, “no” - the message is not considered issued by a source and belonging to a specific communication session.

Before the start of a communication session, a secret parameter is exchanged - the communication session identifier. This code sequence is the basis for generating a pseudo-random sequence, and the generation algorithm is not the subject of the invention. Disjoint bit sequences are extracted from the pseudo-random sequence; to use them as encryption keys, they must be equal in length. The algorithm by which bit sequences are extracted from a pseudorandom sequence is the same for the source and receiver. Thus, an ordered set of cryptographic keys is formed, identical for the source and receiver. Each cryptographic key in this set has its own unique number and is used by the source to encrypt a message with the same sequence number in the communication session in question. Using cryptographic hashing, a message authentication code is generated from an unencrypted message, which is transmitted to the receiver along with the encrypted message. To maintain communication sessions with various sources, the receiver selects from the entire set of keys for each communication session a subset of keys of a certain limited size, which is used when checking each incoming message. The purpose of this is to limit the number of decryptions of an incoming message, since the receiver a priori does not have information about the serial number of the message in the communication session and even information about the belonging of the message to the communication session in question. This information is generated by sequential selection of keys to decrypt the message.

The receiver, using each key of the generated subset of messages, decrypts the message and forms a verification sequence from those obtained using the cryptographic hashing algorithm used by the source, which it compares with the authentication code received along with the message. Authentication code matching means that the message was generated by the source with which data is exchanged in the communication session, and that the sequence number of the message in this communication session is equal to the number of the key, the use of which led to the matching of the authentication codes. The coincidence of authentication codes should cause a change in the composition of the subset of thorns used to decrypt the message in the communication session in question, since the communication protocols used in modern telecommunication networks imply sequential transmission of messages within the communication session, when a message with a larger sequence number is transmitted after a message with a smaller one.

Changing the composition of the subset of keys used to decrypt a message is carried out by adding to it a key with a sequence number one greater than the maximum sequence number of the keys in the subset, and removing the key with the lowest sequence number from the subset.

Claims (1)

A method for determining the source of data packets in telecommunication networks, which consists in the fact that before the start of a communication session, the source and receiver exchange a secret identifier for the communication session, the source and receiver generate identical pseudo-random sequences based on the secret identifier, the source and receiver select non-overlapping ones from the generated pseudo-random sequences in the same way bit sequences that form a set of cryptographic keys for a given communication session; when transmitting a message, the source encrypts it with a key with a serial number equal to the message number in the communication session and, based on the original contents of the message, generates a message authentication code using cryptographic hashing algorithms; the source transmits the encrypted message together with the authentication code of a given message and characterized in that the receiver stores all key sets for all active communication sessions; for each communication session at each moment in time, a certain subset of keys is selected from the set of keys, used to decrypt incoming messages; the message received at the receiver is decrypted for each communication session using all the keys of the entire subset of keys for this communication session, during each decryption procedure the authentication code is checked by comparing the code generated using cryptographic hashing algorithms with the message authentication code received along with the message, the message is considered generated by the source and belonging to a specific communication session if during decryption, the verification of the authentication code was successful, the key number that gave the correct result when checking the authentication code is accepted as the number of the message received by the receiver during the communication session, after each successful verification of the authentication code, the subset of keys for this communication session is changed by removing the key from it with the lowest number and adding a key with a number one greater than the maximum subset key number.