DE10036052B4 - Method and device for securing data connections against unauthorized intervention - Google Patents

Abstract

Method for securing devices in a data transmission network in constant data exchange without a monitored point-to-point connection between two network participants (A, B), characterized in that one for each data transmission from one network partner (A) to the other network partner (B) changing partner random identifier (ZKA _n ,) with each transmission process and the other network partner (B) acknowledges the receipt of the data not with the partner random identifier just received, but with the partner random identifier (ZKA _n-1 ) received in the previous step, such that in the absence of the random identifier required for acknowledgment or the use of the current and not the penultimate random identifier, an error and / or manipulation in the network can be determined.

Description

The Invention is directed to a method for securing in constant Data exchange devices a data transmission network without monitored Point-to-point connection between two network nodes (A, B), as well to an implementation facility of the procedure.

It gives an abundance of applications, where data processing devices are in constant exchange via networks are located, especially at national level working companies, banks, research institutes or the like

In so-called IP networks or ATM networks or similar networks, it is not possible, a monitored Point-to-point connection to disposal to deliver. Monitored at these Networking becomes a point-to-point connection on the application layer (OSI layer 4-7), with the possibility for the participants should be given to detect a failure or sabotage.

at a failure that must be recognized is another interference-free transmission the data is no longer guaranteed, Sabotage can be a targeted attack against you Act participants or against the lower OSI layers 1-3 e.g. by exchanging one Participant and replacement by another with the same IP address, thus ensuring the backup have to be, that data are protected against access by unauthorized third parties.

In order to achieve this goal, ie the detection of network failures or sabotage, with simple means, the invention provides that with each data transmission from one network partner (A) to the other network partner (B), a partner random identifier that changes with each transmission process ( ZKA _n ) is transmitted and the other network partner (B) acknowledges the receipt of the data not with the partner random identifier just received, but with the partner random identifier (ZKA _n-1 ) received in the previous step, such that in the absence of the random identifier required for acknowledgment or an error and / or manipulation in the network can be determined using the current and not the penultimate random identifier.

With the invention it is possible a random identifier for a data packet when exchanging data (with polling) add, being the data sending device assigns a new random identifier, the recipient of the Data packet but the reception with the data transmission step from the previous acknowledged. With the acknowledgment, the receiver becomes the sender at the same time transmitted a new random identifier, which he took at the next but one step then available again for acknowledgment.

Become for example, data processing devices exchanged without authorization when sending data, feature this if necessary via the possibility, with the data recipient to communicate, but they do not have the for correct acknowledgment necessary knowledge of the data transmitted from the previous data transmission step Random identifier so that a such device in principle is only able to use the current random identifier acknowledge the data input. The system would do this immediately recognized as an error. If there is no acknowledgment overall, the Random identification also immediately caused an error.

At this point it should be noted that there are a number of solutions, which however involve the encryption of identification data between two participants. This is how it acts DE-36 19 566-C1 the exchange of identification data from two participants for the purpose of encryption. The article in the IBM Technical Disclosure Bulletin, Vol. 35, No. 3, August 1992, pp. 62-63, "Encrypted data transmission with dynamic key renewal" deals with encryption in data traffic with the possibility of an initialization procedure for the purpose of a key exchange, while the US 5,500,888 describes the assignment of a sender and recipient and exchange of keys.

In the JP-07095218-A describes the synchronization of a master and a slave after a detected failure, while the DE-30 18 945-C2 describes the checking of the admissibility of a connection and a corresponding encryption, with a fixed assignment between transmitter and receiver being carried out with the purpose of recognizing a subscriber.

On Indicating that for sure the detection of a participant can be done to prevent the Exchange of active devices in the system, these references do not show.

Further refinements of the invention result from the subclaims, with one possibility when the method is restarted is that when the system backup is restarted for the first time, the partner, for example a monitoring center (B), is sent a random start identifier (ZKA ₀ ) by the partner (A) and transmits this Random start identifier is acknowledged by partner (B) with the addition of a random start identifier (ZKB ₀ ) from there.

A somewhat modified one, the restart According to the embodiment of the invention, the procedure relating to the monitoring process consists in that when the system backup is restarted for the first time from partner (A) to other partner (B), for example a transmission center, a random start identifier (ZKA ₀ ) is transmitted and the receipt is acknowledged and subsequently by Partner (B) transmits a random start identifier (ZKB ₀ ) to the other partner (A) and the receipt is acknowledged, with a new random identifier, e.g. ZKA ₁ , also being transmitted during the subsequent data exchange and the receipt with the previously received one from the other partner (B) Random identifier (ZKA ₀ ) is acknowledged.

A Plant for implementation According to the invention, the method is characterized by a data connection network and at least two about that Data connection network of data transmission devices in communication with each other, each of the two data transmission devices with one device for the delivery of a changing with each transmission process, the respective device assignable random identifier, each data processing device with a Device for recognizing the respective with transmitted random identifiers and is equipped to issue a warning in the event of errors.

Further Features, details and advantages of the invention result from the following description and the drawing. This shows schedule in all figures after the data exchange according to the invention, namely in

1 a schedule of data transfer with restart,

2 an undisturbed data exchange,

3 a new start of data exchange,

4 the rest phase as well as in the

5 and 6 Fault detection situations.

In the graphic representations means

TS

 transmission center

LEL

 transmission equipment

ZK

 random ID

ZKÜZ _a , ZKÜB _b

 current Random identifier for the next transfer

ZKÜZ _a-1 , ZKÜB _b-1

 Old Random identifier for data legitimation

For example, from 1 The flow chart shows that a random identifier ZKÜG _{0 is} transmitted from the transmission device ÜG to the monitoring center when restarting, which is acknowledged from there. After acknowledgment, the monitoring center transmits a random identifier ZKÜZ ₀ to the transmission device, the receipt of which is acknowledged by the transmission device, the OSI layer 3 being assumed to be sufficient for the acknowledgment.

Now has both the surveillance center as well as the transmission device each Random identifier from the partner.

Are data now transferred ( 2 ), eg from the transmission device ÜG, this adds a new random identifier to the data ZKÜG ₁ connected to the random identifier previously received from the transmission center (here eg ZKÜZ ₁ ). The monitoring center ÜZ now acknowledges the receipt of the data with the penultimate random identifier of the transmission device ZKÜG ₀ and adds a new, own random identifier, eg ZKÜZ ₂ . If the penultimate random identifier is identified as correct by the transmission device, it now activates its next random identifier, ie ZKÜG ₁ , to check incoming data and takes over the following random identifier ZKÜZ ₂ sent to it by the monitoring center.

If no user data are exchanged, the system falls into the procedure referred to here as the "idle phase", for example in accordance with 1 , whereby polling starts between the transmission center and the device, ie line monitoring without user data. For example, 4 ) the polling data packet with a random identifier (there ZKÜZ _a ) connected to the random identifier of the transmission device from the transmission center, there ZKÜG _b-1 transmitted. Now the transmission device acknowledges with the previous identification of the transmission center (there ZKÜZ _a-1 ) and adds a new own random identifier of this data sequence (there ZKÜG _b ). After a predeterminable time T _P , for example <30 seconds, this polling is repeated.

This time interval T _P can be selected, for example, according to VDE 0833 / Part 3 (monitoring time variable, but less than ≤ 30 seconds).

For error detection:
There are different possibilities here, e.g. after 5 If the transmission device transmits a random identifier that is supposedly received from the transmission center, but this is unknown, the error is recognized by the transmission center. A receipt of the data received is not sent.

Become the transmission center now continue to transmit data without the correct random identifiers, they are rejected from there, since it is, for example, data from previous transmissions can trade that are still available on the net. According to the predetermined Polling time then runs again this line monitoring without using user data. Now when polling from the transmission device of the transmission center again transmitted an incorrect identifier, can the transmission center a sabotage at the monitoring device or at determine the relevant participant.

A variant of the error detection is in 6 shown: If the transmission center transmits the polling data packet with the random identifier to the network at predetermined intervals T _W = timer repetition and there is no acknowledgment, the system can detect a fault in the connection, whereby the sending of the same polling data record with the corresponding random identifier is always n- times.

Claims (4)

Method for securing devices in a data transmission network in constant data exchange without a monitored point-to-point connection between two network participants (A, B), characterized in that one for each data transmission from one network partner (A) to the other network partner (B) changing partner random identifier (ZKA _n ,) with each transmission process and the other network partner (B) acknowledges the receipt of the data not with the partner random identifier just received, but with the partner random identifier (ZKA _n-1 ) received in the previous step, such that in the absence of the random identifier required for acknowledgment or the use of the current and not the penultimate random identifier, an error and / or manipulation in the network can be determined. Method according to claim 1, characterized in that when the system backup is restarted for the first time, the partner (A), for example a monitoring center (B), transmits a random start identifier (ZKA ₀ ) from the partner (A) and this random partner identifier is added by the partner (B) with the addition of one originating from there Random start identifier (ZKB ₀ ) is acknowledged. Method according to Claim 1, characterized in that when the system backup is restarted for the first time from partner (A) to other partner (B), for example a transmission center, a random start identifier (ZKA ₀ ) is transmitted and the receipt is acknowledged and subsequently by partner (B) a start random identifier (ZKB ₀ ) is transmitted to the other partner (A) and the input is acknowledged, a new random identifier, for example ZKA ₁ , is also transmitted during the following data exchange and the input with the previously received random identifier (ZKA ₀ ) is acknowledged. Plant in particular for performing the method according to a of the preceding claims, characterized by a data connection network and at least two via the Data connection network of data transmission devices in communication with one another, wherein each of the two data transmission devices with one Device for delivering a changing with each transmission process the respective device assignable random identifier is equipped, each data processing device with a Device for recognizing the respective with transmitted random identifiers and is equipped to issue a warning in the event of errors.