阅读说明：本技术 射频通信系统和方法 (RF communication system and method ) 是由 约翰尼·德克恩·克里斯蒂安森 弗莱明·哈尔德 于 2018-02-09 设计创作，主要内容包括：用于在抄表系统中以无线方式传输数据分组的方法和设备,其中,该方法包括：在该仪表设备处生成第一数据分组,该第一数据分组包括有效载荷数据以及基于该有效载荷数据和存储在该仪表设备的存储器中的相关联仪表数据计算的第一消息认证码；从该仪表设备向该接收器传输该第一数据分组；以及在该接收器处通过使用该接收的有效载荷数据和存储在该接收器的存储器中的当前相关联仪表数据作为输入来重新计算该第一消息认证码而对该第一数据分组执行初级认证检查并验证该相关联仪表数据。(Method and apparatus for wirelessly transmitting data grouping in kilowatt meter reading-out system, wherein, this method comprises: generating the first data grouping at the instrumentation, which includes payload data and the first message authentication code based on the payload data and the associated instrumented data being stored in the memory of instrumentation calculating；First data grouping is transmitted from the instrumentation to the receiver；And the first message authentication code is recalculated as input by using the currently associated instrumented data in the received payload data and the memory for being stored in the receiver at the receiver and primary authentication check is executed to first data grouping and verifies the associated instrumented data.)

1. a kind of for data grouping to be wirelessly transmitted to receiver (14) from the instrumentation (12) of kilowatt meter reading-out system Method, method includes the following steps:

The first data grouping DP1 is generated at the instrumentation (12), which includes being used as payload data Consumption data CD and first message authentication code MAC1, the first message authentication code MAC1 be based on use payload data PD And it is stored in associated instrumented data AMD in the memory of the instrumentation and data encryption key DEK is as input MAC algorithm calculates；

The first data grouping DP1 is transmitted to the receiver from the instrumentation；

At the receiver, by based on using the received payload data PD, be stored in the memory of the receiver Currently associated instrumented data CAMD and data encryption key DEK MAC algorithm as input recalculate this first Message authentication code is stored in the receiver and deposits the received first data grouping PD1 is executed primary authentication check and be verified This in reservoir is currently associated instrumented data CAMD；And

If it is verified be it is true, receive first data grouping.

2. according to the method described in claim 1, wherein, if during the primary authentication check first data grouping not by Receive, then this method further includes steps of

At the receiver, by using the received payload data PD, it is stored in the memory of the receiver Data encryption key DEK and multiple and different associated instrumented data AAMD collection are counted again as the input of the MAC algorithm It calculates the first message authentication code and secondary authentication inspection is executed to the first data grouping PD1；

If different one of the associated instrumented data collection causes to match with the first message authentication code, then it is assumed that this first Data grouping may be true and first data grouping be stored in the buffer memory of the receiver；

The second data grouping DP2 is generated at the instrumentation and transmits the second data grouping DP2 from the instrumentation To the receiver, which includes the consumption data CD2 and second message authentication code as payload data PD2 MAC2；

At the receiver, by using with payload data PD2, data encryption key DEK and in the secondary authentication The associated instrumented data MAC algorithm as input identified during inspection recalculating the second message authentication code and Three-level authentication check is executed to the second data grouping DP2；

If this, which is recalculated, causes to match with second authentication code, receive first data grouping and second data point Group is true.

3. method according to any of the preceding claims, wherein the associated instrumented data is to reflect that the instrument is set The data of standby configuration parameter, such as the instruction of measurement unit, data resolution or storage register, for use as the consumption data Input.

4. method according to any of the preceding claims, wherein if during the three-level authentication check this first Data grouping and second data grouping are accepted as really, then updating the currently associated instrumented data CAMD.

5. method according to any of the preceding claims, wherein in conjunction with the initial installation of the instrumentation, in conjunction with this The current associated instrumented data CAMD is initially input the buffer memory of the receiver by the recalibration of instrumentation In.

6. method according to any of the preceding claims, wherein the payload data PD of the data grouping and The message authentication code is encrypted by the instrumentation before being transmitted, and is then decrypted by the receiver.

7. a kind of instrumentation (12) for measuring fluid flow rate or for sensing another parameter, the instrumentation include:

Processor, the processor are configured as calculating consumption data based on the parameter of the flow rate measurement or the sensing；

Transmitter, the transmitter are used to transmit data grouping via radio communication；

Wherein, which is configured to method according to any one of claim 1 to 6 and executes generation and biography Transmission of data is grouped the step of DP1, DP2.

8. a kind of for receiving the receiver (14) of the data grouping by instrumentation transmission, which includes for executing such as The side described in any one of claims 1 to 6 for being related to receiving data grouping and checking the certification to the received data grouping The device of the step of method.

9. a kind of radio communication protocol, which includes for setting the instrument as described in claim 7 and 8 The instruction for the step of standby and receiver executes the method as described in claim 1.

Technical field

The present invention relates to a kind of radio frequencies for the wirelessly transmitting data grouping between two communication nodes of communication network Communication system and method.More particularly it relates to a kind of for ensureing the Authenticated Encryption Schemes of the validity of transmission data.

Background technique

Automatic data logging (automatic meter reading, AMR) system and advanced measurement system (advanced Meter infrastructure, AMI) system is commonly known in this field.Utilities use this system, lead to It is often used radio frequency (RF) communication and remotely to read and monitor consumption instrument.The AMR system and AMI system for being referred to as kilowatt meter reading-out system mention The high efficiency and accuracy for collecting reading and managing customer bill.

AMR system collects meter reading and data usually using mobile RF communication network, and AMI system uses fixation RF communication network.Especially in AMI system, it is understood that there may be multiple interceptor(-ter)s throughout larger geographic area, Mei Geshou Storage is for example led to by using wide area network (WAN) or other suitable communications infrastructures with central back-end system in turn Letter.AMI system can also be using in the overlay area having by forwarding meter reading and data to extend each reader After the system of device or trunking.In mobile network's AMR environment, when mobile reader moves everywhere, using logical with RF Hand-held, vehicular or other movement readers of letter ability to collect data from instrumentation.

Metering system for measuring public utility consumption may include be provided with RF signal for transmitting and receiving logical Believe the instrumentation of the intelligence instrument form of equipment.These communication equipments are configurable to periodically transmit data grouping (data packet), these data groupings include the data for indicating multiple meter readings and other instrument according to time change Table data.These data groupings are handled, transmitted and modified according to communication protocol by receiver apparatus.

Instrumentation is usually battery powered, and therefore there is limited energy can be used for its seeervice cycle.Due to instrument The seeervice cycle of table equipment is usually 10 to 20 years, therefore in order to reduce cost associated with instrument replacement or battery replacement, Energy conservation is main design objective.It is relevant to communication for having the utility meter for the feeder cable that can be used as power supply Energy conservation may be also it is desirable that.

Since radio packet transmission accounts for a big chunk that energy in instrumentation uses, more efficient transmitting and Reception may use energy (i.e. the battery life of instrumentation) to have and significantly affect.Therefore, if can reduce for passing The power of transmission of data grouping, then this will have positive influence to the total power budget of instrumentation.Reduce one kind of transimission power Method is by reducing transmitted data amount and data packet length.However, transimission power is usually reliable with transmission quality and reception Property is closely related, this is also very important.The common cause of low transmission q&r is path loss, collision, congestion Deng.

Another significant design index of utility meter communication system is communication security.Communication system must include using In ensuring that the data grouping transmitted between instrumentation, repeater, collector and back-end system is true and transmitting The measure that period is not tampered with.In addition, consumption data is considered as personal information in many jurisdictions.Therefore, it is necessary to anti- Such data are intercepted, only to ensure that unauthorized party cannot access data.

It can be by meter reading and other data (such as alarm or sensing data) as packets of data from instrument Equipment is transmitted to back-end system, and back-end system can will include order or the data packet transfer updated to instrumentation. The robustness and the system of reliability and communication system are via possible intermediate equipment successfully by data grouping from transmitter The ability for being transmitted to correct receiver is related.If grouping is failed to reach receiver, need to transmit grouping again, this is It is undesirable.

Accordingly, there exist the demands to improved communication system, wherein is not damaging transmission quality, reception reliability and is leading to Transimission power is reduced in the case where letter safety.

Goal of the invention

The object of the present invention is to provide the alternative solutions of the prior art.Particularly, the purpose of the present invention can be regarded as It provides and a kind of needs the data volume transmitted to provide the method for safe and effective communication in smart electric grid system by reducing.

Summary of the invention

Therefore, in the first aspect of the present invention, it is intended to a kind of for wirelessly by data grouping from copying by providing The instrumentation of table system is transmitted to the method for receiver to obtain above-mentioned purpose and several other purposes, and this method includes following Step: it at the instrumentation, generates the first data grouping (data packet, DP1), which includes conduct The consumption data (comsumption data, CD) and first message authentication code (message of payload data Authentication code, MAC1), which is based on using the payload data (payload data, PD) and the associated instrumented data (associated being stored in the memory of the instrumentation Meter data, AMD) and data encryption key (data encryption key, DEK) MAC algorithm as input count It calculates；First data grouping (DP1) is transmitted to the receiver from the instrumentation；At the receiver, by using with this It received payload data (PD), the data encryption key (DEK) being stored in the memory of the receiver and is stored in Currently associated instrumented data (current associated meter data, CAMD) in the memory of the receiver is made For the MAC algorithm of input primary is executed to first data grouping (DP1) and is recognized recalculating the first message authentication code Card checks；And if it is verified be it is true, receive first data grouping.

In this respect, receiver can be interpreted self contained facility, such as the collector or concentrator of kilowatt meter reading-out system, or Person is interpreted the integration section of back-end system.It can be directly or indirectly via for by data packet relay, again transmit Or multiple trunkings of back-end system are forwarded to by data packet transfer to receiver.

In addition, instrumentation can be for measure, measure or sense with equipment itself or with certain environmental condition or set Any kind of equipment of the relevant parameter of variation of standby environmental condition.Instrumentation may include for measuring such as fluid etc. The device that particle level or particle in substance or in surrounding air exist or be connected chemically.

By applying communication means defined above, (packet) is grouped to reduce when being associated instrumented data by omission Payload when, total packet length can be greatly reduced.However, since what receiver must be known by being used by instrument is associated Instrumented data is to be correctly inferred to the consumption data of transmission from including in information in data grouping, therefore the communication defined Method allows receiver to verify associated instrumented data.

In addition, being executed when using first message authentication code is recalculated by the associated instrumented data that receiver stores Primary the step of authenticating of first data grouping, can be further believed to comprise in the memory for being stored in receiver The actual verification of currently associated instrumented data.

In addition, payload data (PD) can be made of consumption data (CD).Therefore, consumption data is in data grouping Unique payload.Remaining data grouping is made of overhead data, may include for supporting to be used by communication system Protocol type data and for support the mistake caused by data grouping during transmitting among the nodes is carried out Detection and optionally corrected redundancy check data.

In addition, this method can if the first data grouping is not received during the primary authentication check of the above method To further include steps of at the receiver, by using the received payload data PD, it is stored in the reception Data encryption key DEK and multiple and different associated instrumented data (AAMD) collection in the memory of device are used as the MAC The input of algorithm executes secondary authentication inspection to first data grouping (DP1) to recalculate the first message authentication code； If different one of the associated instrumented data collection causes to match with the first message authentication code, then it is assumed that first data point Group may be true and first data grouping be stored in the buffer memory of the receiver；At the instrumentation It generates the second data grouping (DP2) and second data grouping (DP2) is transmitted to the receiver from the instrumentation, this Two data groupings include the consumption data (CD2) and second message authentication code (MAC2) as payload data (PD2)；At this At receiver, by using with the payload data (PD2), the data encryption key (DEK) and in the secondary authentication inspection The associated instrumented data MAC algorithm as input of period mark come recalculate the second message authentication code and to this Second data grouping (DP2) executes three-level authentication check；If this, which is recalculated, causes to match with second authentication code, receive First data grouping and second data grouping are true.

In addition, the associated instrumented data can reflect the configuration parameter of the instrumentation, such as measurement unit, data point The instruction of resolution or storage register, the input as the consumption data.In addition, if during the three-level authentication check this One data grouping and second data grouping are accepted as really, then can update the currently associated instrumented data (CAMD).In addition, in conjunction with the initial recalibration installed and combine the instrumentation of the instrumentation, it can be by current phase Association instrumented data CAMD is initially input in the buffer memory of the receiver.In addition, the payload number of the data grouping It can be encrypted by the instrumentation according to (PD) and message authentication code, and then be decrypted by the receiver before being transmitted.

According to the second aspect of the invention, it is intended to by the flow rate (flow rate) for measuring fluid or for sensing The instrumentation (12) of another parameter obtains above-mentioned purpose and several other purposes, which includes: processor, at this Reason device is configured as calculating consumption data based on the parameter of the flow rate measurement or the sensing；Transmitter, the transmitter are used In transmitting data grouping via radio communication；Wherein, which is configured to be held according to the process described above The step of row generation and transmission data grouping (DP1, DP2).Further, processor can be the one of processing circuit or processor Part, and discrete parts can be used and be implemented as integrated circuit or ASIC.

According to the third aspect of the invention we, it is intended to pass through the receiver for receiving the data grouping by instrumentation transmission (14) above-mentioned purpose and several other purposes are obtained, which includes for executing such as any one of claims 1 to 6 institute Device the step of being related to receiving data grouping and check the method to the certification of the received data stated.

According to the fourth aspect of the invention, it is intended to which above-mentioned purpose and other several mesh are obtained by radio communication protocol , which includes for executing instrumentation as described in claim 7 and 8 and receiver as right is wanted The instruction of the step of method described in asking 1.

Above-mentioned MAC algorithm can be based on various error detection schemes, such as cyclic redundancy check (CRC), verification and or the Chinese Plain code.MAC algorithm based on encryption method is usually also used as example such as based on aes algorithm or other appropriate algorithms CMAC or CBC-MAC scheduling algorithm.Message authentication code (message authentication code, MAC) can also be known as message Integrity code (message integrity code, MIC).

In addition, as stated above, payload data (PD) can be made of consumption data (CD).Therefore, it consumes Data are unique payload in data grouping.Therefore, payload data does not include comprising instrument identification number, measurement unit The associated instrumented data with Measurement Resolution.The common ground of all associated datas is the configuration parameter phase of data with instrument It closes, these parameters are substantially static and therefore only can just change when intentionally reconfiguring instrument.This with include The payload data of the consumption data changed over time and inherently is opposite.

Detailed description of the invention

Method, equipment and communication protocol according to the present invention will be more fully described about attached drawing now.Attached drawing exhibition Shown implementation mode of the invention, and should not be construed as being limited to fall within the scope of the appended claims other can The embodiment of energy.

Fig. 1 illustrates kilowatt meter reading-out system,

Fig. 2 shows the schematic diagrams for showing radio packet, and

Fig. 3 illustrates instrumentation.

Specific embodiment

The present invention can be implemented by hardware, software, firmware or these any combination.The present invention or some features Also it may be implemented as the software run on one or more data processors and/or digital signal processors.Of the invention Each element of embodiment can physically, functionally and logically be implemented in any suitable manner, such as single single A part in member, in multiple units or as individual functional unit.The present invention can be implemented in individual unit, or It is physically and functionally distributed between different unit and processor.

With reference to Fig. 1, the RF communication system 1 for kilowatt meter reading-out system form is illustrated.Kilowatt meter reading-out system includes being mounted on correspondence to make With at be configured for multiple instrumentations 10 of data packet transfer to receiver 30 via radio communication.Shown in In exemplary kilowatt meter reading-out system, receiver is implemented as a part of back-end system.Kilowatt meter reading-out system further comprises one or more Collector device 20, the collector device are used to communicate via radio frequency (RF) and be communicated with instrumentation, and according to meter reading The geographical distribution of system may include multiple relay equipments 101 with by data grouping from instrumentation relay to this or Multiple collectors.It connects wirelessly or via cable and data grouping is transmitted to back-end system 30 from collector device 20. In addition, multiple mobile collecting device (not shown) may include in systems, collecting as to fixed in alternative system configuration Device equipment it is substituted or supplemented.In one-way communication configuration, instrumentation is configured for data via collector device Grouping is transmitted to the dedicated transmitter equipment of receiver, and in two-way communication configuration, instrumentation, collector device and rear end Each of system is all configured to not only transmit data grouping but also receives data grouping.

It will be appreciated by the skilled person that equipped with different communication module other network equipments (for example, router device or Instrumentation) it also may include in above-mentioned kilowatt meter reading-out system.At least between instrumentation and collector and/or relay equipment Communication communicated based on RF, and the transmission between collector device and back-end system can be any suitable type, than if any Line transmission or wireless transmission.Further, it will be appreciated by the skilled person that for illustrative purpose, shown in kilowatt meter reading-out system only Network components including limited quantity.

Referring to Fig. 3, each instrumentation 10 includes measuring device, which includes being configured as measurement via public Facility network is transported to the metering circuit 11 of the amount of the specific utility (such as water or electricity) of corresponding point of use.It is tied based on measurement Fruit calculates consumption data CD and stores it in the register of memory 13 of instrumentation.In addition to flow and actual consumption Except data, consumption data can also include related to relevant or with instrumentation the operation of measurement executed by metering circuit Other kinds of data, such as polymerization traffic, flow rate, leakage instruction, distort warning, environment temperature.Broadest consumption number The survey executed according to the other sensors that can also cover by being integrated in instrumentation or the sensor operated as autonomous device Amount.In another embodiment (not shown), therefore instrumentation can be for sensing in addition to flow and/or being transported to use The equipment of parameter except the public utility amount of point.

According to the type of consumption data, store data in the different registers of memory 13.Memory 13 also stores Reflect the associated instrumented data AMD of the configuration parameter of instrumentation.For example, as will be described further, being associated instrument Which register of table data designated memory should be used as the input of the data grouping generated by instrumentation.Associated instrument Data further include in register about the measurement unit for the input for being used as generated data grouping and the information of data resolution.Cause This, associated instrumented data AMD is data needed for explaining or encoding consumption data CD.Do not knowing associated instrumented data In the case of, consumption data cannot be used.

The further storage data encryption key DEK of memory 13 of instrumentation.(multiple) data encryption key can be It is stored when instrument initial configuration, or is loaded into instrument storage in later phases (such as in more new session or during reconfiguring) In device.

During operation, the processing unit 12 of instrumentation is configurable to generate including as unique payload data The data grouping DP of consumption data CD, as shown in Figure 2.Other than payload, data grouping further includes overhead data Or redundant data, the overhead data or redundant data include message authentication code MAC.It is based on using payload by processing unit 12 Data PD, it is associated instrumented data AMD and data encryption key DEK MAC algorithm as input to calculate message authentication code MAC.Overhead data further comprises packet preamble part PP, sync section SP, block length field PL.Overhead data also wraps Include the information about the real time of data grouping and instrument mark.Therefore, data grouping does not include needed for explaining consumption data Associated instrumented data.For the recipient using the data, it is therefore necessary to by other means (for example, passing through previously Configuration) keep associated instrumented data available.By omitting associated instrumented data, the size of the payload of data grouping Substantially reduce such as 30% to 50%.Since payload accounts for about half of actual packet size, associated instrument is omitted Total data packet size can be reduced about 25% by table data, this can again lead to sizable reduction of transimission power.

Further, instrumentation further comprises transmission circuit 14, which includes for passing data grouping Transport to the antenna of the receiver of kilowatt meter reading-out system.Receiver can be implemented or be carried out in one or more collector devices 20 For a part of back-end system 30.In the case where the receiver that rear end is implemented, all instrumentations of kilowatt meter reading-out system are all divided The identical receiver of dispensing.In the embodiment that receiver is implemented in collector, instrumentation is divided into subgroup and divides The different collector device of dispensing.Further, in one configuration, in addition transmission circuit and antenna can be configured for making It is operated for the receiver for receiving data grouping from back-end system and collector device.

Receiver 20,30 includes associated memory, the associated memory storage data encryption key and is distributed to The associated instrumented data of its each instrumentation.Since associated instrumented data can change over time, such as such as Fruit instrument is replaced or is reconfigured, then the memory of receiver stores the set of currently associated instrumented data CAMD, It is considered as currently valid associated instrumented data.Receiver, which is additionally provided with, controls its processing unit operated, and by It is configured to execute the MAC algorithm also applied by instrumentation.

When receiving data grouping by receiver, receiver is configured as determining whether data grouping is from credible instrument The valid data grouping and judgement of equipment transmission include whether the data in data grouping have been damaged during the transmission.For This, receiver is configured as executing received data grouping (hereinafter the first data grouping DP1) primary authentication check.This It is to be added by running the payload data PD used include in the first data grouping with the data stored by processing unit Key DEK and the currently associated instrumented data CAMD MAC algorithm as input of corresponding instrument recalculate first The message authentication code (hereinafter first message authentication code MAC1) of data grouping and complete.If recalculate first disappears Breath authentication code received first message authentication code together with the first data grouping is identical, then the first data grouping is considered It is true and is accepted as effective.

Authentication check is executed by using the currently associated instrumented data CAMD stored, in addition to determining partial data point Except the authenticity of group, receiver also verifies the associated instrumented data of storage.Therefore, associated instrument is not received actually In the case where table data, receiver ensures that the associated instrumented data for explaining the received consumption data is correct.Such as Fruit is used to generate the associated instrumented data of message authentication code and the currently associated instrument stored by receiver by instrumentation Data are different, then primary authentication check will failure.

If during primary authentication check the first data grouping be considered be not it is true, first according to grouping receive into One step inspection to determine validity completely.It is possible to distort or other deception sexualities may cause the failure of primary authentication check. However, as previously discussed, if by receiver storage currently associated instrumented data to be stored in it is related in instrumentation It is different to join instrumented data, then authentication check may also fail.

Therefore, if primary authentication check failure, executes secondary authentication inspection to the first data grouping DP1.Mesh thus , the associated instrumented data AAMD collection of multiple substitutions is stored in the memory of receiver.The associated instrumented data of substitution AAMD collection reflects the possibility instrument arrangement of limited quantity, such as 10 to 100 kinds of different configuration settings.Secondary authentication inspection packet Include use the associated instrumented data AAMD collection of received payload data PD, the data encryption key DEK and substitution as First message authentication code is recalculated in the input of MAC algorithm.If one of the associated instrumented data AAMD collection of substitution causes Matching between the message authentication code recalculated and the received message authentication code, then the first data grouping be deemed likely to be Really.Therefore, if finding the matching with first message authentication code, the first data grouping is considered temporarily effective and deposits Storage is in the buffer memory of receiver.Receiver is further cached for the first data grouping to be considered as and may really substitute The set of associated instrumented data collection (hereinafter is referred to as matching associated instrumented data (matching associated meter data)MAMD)。

Then receiver waits from instrumentation and receives next data grouping (hereinafter the second data grouping DP2).In The second data grouping is identically generated with the first data grouping at instrumentation.It is counted when generating second in later point According to grouping when, including in the second data grouping payload data PD and message authentication code changed.Therefore, the second number It include payload data PD2 and second message authentication code MAC2 according to grouping.

The second data grouping is received, receiver first executes the second data grouping and as described above to the first data grouping The similar primary authentication check of the primary authentication check of execution.If (i.e. based on currently associated after primary authentication check Instrumented data) the second data grouping be considered as it is true, then store currently associated instrumented data in the receiver CAMD is considered effective and the second data grouping is accepted as effectively.On the other hand, the first buffered data point Group and then to be rejected be invalid.

If the second data grouping is considered not being really that receiver, which executes three-level, to be recognized after primary authentication check Card checks.Three-level authentication check includes related to matching using received payload data PD2, the data encryption key DEK Connection instrumented data MAMD checks second message authentication code MAC2 as the input of MAC algorithm.If matching associated instrument number Also cause to match with second message authentication code MAC2 according to MAMD, then receiver receives the first data grouping and the second data grouping two Person is true.However, matching input of the associated instrumented data MAMD as MAC algorithm without result in matching if used (that is, value equal with second message authentication code), then the first data grouping is all rejected.

By using this method, it is ensured that thinking that at least two is continuous using identical associated instrumented data AMD collection Before received data grouping is true, currently associated instrumented data CAMD is not updated.This is with following advantageous effects: The intensity of MAC will not be weakened by secondary authentication process, and plurality of different associated data AMD collection is for calculating.MAC's is strong Degree is understood to will test the probability of authenticated or associated data change when application MAC algorithm.Therefore, for having High-intensitive MAC, detects that the probability of data variation is very high.

The ratio that MAC is only weakened in secondary authentication will likely be equal to the number of the associated instrumented data AAMD collection substituted Amount.If intensity of the quantity of the associated instrumented data AAMD of substitution equal to 16, MAC will be weakened 16 times, this is equivalent to The length of MAC is reduced 4.Therefore, if this method receives new associated instrumented data for secondary authentication inspection is based only upon Collection, then the intensity of the authenticity examination of system will be less than the inherent strength of the MAC defined by the digit in MAC.In addition, reduction will It can be changed according to the quantity of the associated instrumented data AAMD collection of substitution, therefore cannot will define well recognizing for the reception data Card and integrality intensity.

Including an associated data (matching associated instrumented data MAMD) collection is used only to new payload data PD2 collection carries out the inherent strength that the three-level authentication check of authenticity examination will have the MAC defined by the digit in MAC.Therefore, Secondary authentication and the combined strength of three-level certification may never be less than the inherent strength of the MAC defined by the digit in MAC.

It will be appreciated by the skilled person that if it is desire to protection in addition to payload data PD, associated instrumented data AMD and These other parts can be included then in the calculating of MAC by the other parts of the data packet except data encryption key DEK. These other parts can be but not limited to one or more elements of overhead data, such as instrument mark, block length, grouping Type or temporal information.Further, if MAC, which is calculated, is based on cryptographic methods, for example aes algorithm or other suitable encryptions are calculated Method, then these cryptographic methods may include initialization vector.Data to be protected element may include in this initialization vector In.It particularly, include the time in initialization vector or being increased continuously counter can be beneficial to prevent grouping from replaying.

Although having been combined specific embodiment describes the present invention, it is not necessarily to be construed as being confined to institute in any way The example provided.The scope of the present invention should be explained according to appended claims.In the background of claim, term " comprising " or " comprises " is not excluded for other possible elements or step.In addition, referring to such as " a " or " an " etc. It is not construed as excluding multiple.The appended drawing reference used in claim about element indicated in attached drawing should not also be solved It is interpreted as limiting the scope of the invention.Furthermore, it is possible to it may be advantageously combined in each feature mentioned in different claims, and And the combination for referring to that feature is not precluded in these features in different claims is impossible and advantageous.