A method for improving the trustworthiness of a result set, a method and system for supporting traceability

Abstract

The application provides a trust degree improving method of a result set, comprising the following steps: S a1, in the process of analyzing a result set file, splicing the field contents of each piece of data, respectively calculating the MD5 of each piece of data after splicing as data HASH, correspondingly generating multiple data tables containing the data HASH, and forming a database by the multiple data tables; S a2, calculating the table name MD5 of each data table as a table name HASH, and storing the table name HASH to form a TABLE information table; S a3, calculating the file MD5 of the database as a database file HASH, and storing the database file HASH to form a DATABASE information table; and S a4, updating the data table, the TABLE information table and the DATABASE information table into the result set file. The application improves the trust degree of the result set by multiple tests on the result set.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data forensics, and in particular to a result set trust degree improvement method, a support traceability method and system. BACKGROUND

[0002] With the progress of science and technology, electronic products have become necessities of life for the public. In addition to computers and mobile phones, there are also Internet of Things devices such as drones, robotic vacuum cleaners, and smart glasses. These products are collectively referred to as smart devices. As long as a device is a smart device, there may be user-related data in the device or corresponding cloud, and these data can be applied to the field of electronic data forensics and analysis.

[0003] There are many forensic and analysis products on the market that are targeted at specific types of devices and specific storage locations. For example, there are forensic and analysis products for mobile phones, computers, Internet of Things devices, and cloud data. After the forensic product analyzes the original data, it generates its own result set. The generated result set is currently considered to be trustworthy by default, and no verification is performed when it is displayed or analyzed later.

[0004] However, during the subsequent transmission and use of the result set, some data or files may be damaged due to uncertain factors, and there is also the possibility of human tampering with the data. If no trustworthiness verification is performed, the event development may be affected by false data. Therefore, it is necessary to provide a method that can improve the trustworthiness of the result set and trace the origin of the result set. SUMMARY

[0005] To solve the above technical problems, the present application provides a result set trust degree improvement method, a support traceability method and system.

[0006] According to a first aspect of the present application, a result set trust degree improvement method is provided, comprising the following steps:

[0007] Sa1, during the process of analyzing the result set file, splicing the content of each field of each data, calculating the MD5 of each spliced data as a data HASH, and generating a plurality of data tables containing the data HASH, and the plurality of data tables constitute a database;

[0008] Sa2, calculating the table name MD5 of each data table as a table name HASH, and storing the table name HASH to form a TABLE information table;

[0009] Sa3, calculating the file MD5 of the database as a database file HASH, and storing the database file HASH to form a DATABASE information table; and

[0010] Sa4, updating the data table, the TABLE information table and the DATABASE information table into the result set file.

[0011] Preferably, in the process of generating the data HASH, the table name HASH and the database file HASH, an interference factor is added to the spliced data, the table name of the data table and the file of the database, respectively.

[0012] Preferably, the TABLE information table in the step Sa2 further stores the number of data in each data table.

[0013] Preferably, the DATABASE information table in the step Sa3 further stores the number of file modifications of the database.

[0014] Preferably, the DATABASE information table in the step Sa3 further stores the file modification time of the database.

[0015] Preferably, in the step Sa1, the MD5 of each data after splicing is calculated during the parsing process of the result set file and / or after the parsing is completed.

[0016] According to a second aspect of the present application, a traceability supporting method for a result set is provided for supporting the traceability of the result set described above, comprising the following steps:

[0017] Sb1, inputting a sample file into a data forensics device, the data forensics device generating a unique digital signature A, the data forensics device generating the result set file after forensics of each sample in the sample file, the result set file generating a digital signature B, and combining the digital signature A, the digital signature B, the starting time of forensics, the forensics unit and the operator information into an initial binding credential; and

[0018] Sb2, using a private key of an asymmetric encryption algorithm to encrypt the initial binding credential and chain the encrypted credential.

[0019] Preferably, after the step Sb2, further comprising:

[0020] Sb3, when the result set file is transferred to other equipment, the other equipment generating a unique digital signature C, and combining the digital signature B, the digital signature C, the transfer time, the handling unit and the operator information into a transfer credential; and

[0021] Sb4, using a private key of the asymmetric encryption algorithm to encrypt the transfer credential and chain the encrypted credential.

[0022] According to a third aspect of the present application, a trust degree improving system of a result set is provided, comprising:

[0023] A data table generating module is configured to splice the field contents of each piece of data in the process of parsing the result set file, calculate the MD5 of each piece of data after splicing as a data HASH, and generate a plurality of data tables containing the data HASH, wherein the plurality of data tables constitute a database.

[0024] A TABLE information table generating module is configured to calculate the table name MD5 of each data table as a table name HASH, and store the table name HASH to form a TABLE information table.

[0025] A DATABASE information table generating module is configured to calculate the file MD5 of the database as a database file HASH, and store the database file HASH to form a DATABASE information table.

[0026] An updating module is configured to update the data table, the TABLE information table and the DATABASE information table into the result set file.

[0027] According to a fourth aspect of the present application, a traceability supporting system of a result set is provided, comprising:

[0028] An initial credential obtaining unit is configured to input a sample file into a data forensics device, the data forensics device generates a unique digital signature A, the data forensics device generates the result set file after forensics of each sample in the sample file, the result set file generates a digital signature B, and the initial binding credential is combined by the digital signature A, the digital signature B, and the starting time of forensics, the forensics unit and the operator information.

[0029] An initial credential encryption unit is configured to use a private key to encrypt the initial binding credential by using an asymmetric encryption algorithm.

[0030] Preferably, further comprising:

[0031] A flow credential obtaining unit is configured to combine the digital signature B, the digital signature C, and the flow time, the handling unit and the operator information into a flow credential when the result set file is transferred to other devices.

[0032] A flow credential encryption unit is configured to use a private key to encrypt the flow credential by using the asymmetric encryption algorithm.

[0033] According to the fifth aspect of the present application, a computer-readable storage medium is proposed, which stores a computer program. When the computer program is executed by a processor, it implements the trust improvement method and traceability method of the result set as described in the first and second aspects of the present application.

[0034] This application proposes a method for improving the trustworthiness of result sets, as well as a method and system for supporting traceability. By generating hashes layer by layer for a field, a piece of data, a data table, and even an entire database file in a result set file, interference factors are added to increase the difficulty of cracking. Multiple tests, from fine-grained to coarse-grained, are performed to improve the trustworthiness of the result set. Furthermore, the result set incorporates blockchain technology to support tracing the process of result set generation, use, and archiving. This helps improve the judicial validity of the result set and prevents erroneous data from misleading the direction of events. It can complement electronic data forensics technology, is highly practical, and has application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate the embodiments and, together with the description, serve to explain the principles of the present application. Other embodiments and many of the expected advantages of the embodiments will be readily apparent as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale with respect to each other. Like reference numerals designate corresponding similar parts.

[0036] Figure 1 is a flow chart of a method for improving the trustworthiness of a result set according to an embodiment of the present application;

[0037] Figure 2 This is a schematic diagram of the process of generating verification information from fine granularity to coarse granularity according to a specific embodiment of the present application;

[0038] Figure 3 is a flowchart of the verification of a result set file according to a specific embodiment of the present application;

[0039] Figure 4 This is a flow chart of a method for supporting traceability of a result set according to an embodiment of the present application;

[0040] Figure 5 This is a schematic diagram of a method for supporting traceability of a result set according to a specific embodiment of the present application;

[0041] Figure 6 This is a flow chart of tracing the source of a specified result set file according to a specific embodiment of the present application;

[0042] Figure 7 is a block diagram of a system for improving the trustworthiness of a result set according to an embodiment of the present application;

[0043] Figure 8 is a support traceability system block diagram of a result set according to an embodiment of the present application.

[0044] Reference signs: 1, data table generation module; 2, TABLE information table generation module; 3, DATABASE information table generation module; 4, update module; 5, initial credential acquisition unit; 6, initial credential encryption unit; 7, flow-through credential acquisition unit; 8, flow-through credential encryption unit. DETAILED DESCRIPTION

[0045] The features and exemplary embodiments of various aspects of the present application will be described below in detail, in order to make the purposes, technical solutions and advantages of the present application more clear and apparent, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application, and are not configured to limit the present application. The present application can be implemented without some of these specific details for those skilled in the art. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0046] It should be noted that in this paper, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the elements defined by the statement "include" do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0047] According to the first aspect of the present application, a trust degree improvement method of a result set is proposed. The method mainly includes two aspects of generation of data HASH value in the original data table of the result set file and additional generation of encrypted check information file, which contains multi-level granularity check information. Figure 1 shows a flowchart of a trust degree improvement method of a result set according to an embodiment of the present application, Figure 2 shows a schematic diagram of the generation process of check information from fine granularity to coarse granularity according to one specific embodiment of the present application, as Figure 1 、 Figure 2 The method includes the following steps:

[0048] Sa1, in the process of parsing the result set file, the contents of each field of each data are spliced, the MD5 of each spliced data is calculated as data HASH, and a plurality of data tables containing data HASH are generated correspondingly, and the plurality of data tables constitute a database.

[0049] In a specific embodiment, the contents in each field of each data are spliced, and then the MD5 of the spliced contents is calculated as data HASH, as shown in Table 1 below. In this process, in order to avoid being simply deduced to obtain the HASH composition method, an interference factor is spliced after the contents of each field are spliced, so as to improve the cracking difficulty. After obtaining the data HASH, a plurality of data tables can be generated correspondingly, and the data table can contain one or more data HASH, in addition to which, other field values other than the data HASH can also be contained.

[0050] Attribute Name Attribute Description Col1 Data Field 1 Col2 Data Field 2 Col3 Data Field 3 … … DataMD5 Data HASH

[0051] Table 1

[0052] In a specific embodiment, the MD5 check information of each data is generated, and in the case of large data volume, the time consumption is prolonged, therefore, the MD5 of each spliced data (i.e. HASH calculation) can be performed in two stages: writing in the parsing process of the result set file or updating after the parsing is completed. In practice, the selection can be made according to the efficiency requirement of each stage.

[0053] Sa2, the table name MD5 of each data table is calculated as table name HASH, and the table name HASH is stored to form a TABLE information table.

[0054] In a specific embodiment, an interference factor is added to the table name of each data table for HASH calculation to improve the cracking difficulty. In a preferred embodiment, the number of data in each data table is also stored in the TABLE information table, and an additional check is added in the subsequent check, so as to improve the accuracy of the check. The TABLE information table is shown in Table 2 below.

[0055]

[0056] Table 2

[0057] Sa3, the file MD5 of the database is calculated as database file HASH, and the database file HASH is stored to form a DATABASE information table.

[0058] In a specific embodiment, an encrypted check information file is first created, a DATABASE information table is created in the encrypted check information file, then a disturbance factor is added to the database file for HASH calculation to increase the difficulty of cracking, and finally the database file HASH is stored in the DATABASE information table.

[0059] In a preferred embodiment, the DATABASE information table also stores the number of file modifications of the database and the last modification time, and two additional checks are added in the subsequent check, thereby improving the accuracy of the check. The DATABASE information table is shown in Table 3 below.

[0060]

[0061] Table 3

[0062] The number of modifications of the database file can be obtained at the positions of 0x18-0x1B of the database, as shown in Table 4 below.

[0063]

[0064] Table 4

[0065] Sa4, update the data table, TABLE information table and DATABASE information table to the result set file.

[0066] In a specific embodiment, the data table, TABLE information table and encrypted check information file are updated to the result set file.

[0067] After the result set file is obtained by updating, the result set file is used for check, Figure 3 a check flowchart of the result set file according to one specific embodiment of the present application is shown, as Figure 3 As shown, the check steps are as follows:

[0068] Step 1, check whether the DATABASE information table is consistent, if yes, directly display the result, if not, continue to execute check step 2;

[0069] Step 2, check each data table in the result set file, check whether there is an inconsistent table name HASH in the TABLE information table, if yes, identify the abnormal table name and continue to execute check step 3, if not, directly execute check step 3;

[0070] Step 3, check whether there is a data table with inconsistent data number in the TABLE information table, if yes, identify the difference value of the data table and continue to execute check step 4, if not, directly execute check step 4;

[0071] Step 4, check each data in the data table, check if there is inconsistent data HASH, if yes, identify abnormal data and show the result, if not, directly show the result.

[0072] Through the trust degree improvement method of the above result set and the result set checking method, the trust degree of the result set can be improved, and abnormal data can be found and identified. In addition to being trusted, the result set also needs to support traceability.

[0073] According to the second aspect of the application, a result set supporting traceability method is provided, which can support the traceability of the result set obtained by the method of the first aspect of the application. Figure 4 The result set supporting traceability method flow chart according to the embodiment of the application is shown, Figure 5 The result set supporting traceability method according to one specific embodiment of the application is shown, as shown in Figure 4 、 Figure 5 The method includes the following steps:

[0074] Sb1, the test material file is connected to the data forensics device, the data forensics device generates a unique digital signature A, the data forensics device takes evidence of each test material in the test material file to produce a result set file, the result set file generates a digital signature B, and the digital signature A, the digital signature B and the start of the evidence time, the evidence unit, the operator information are combined into an initial binding credential.

[0075] In a specific embodiment, the test material file is connected to the data forensics device, and the data forensics device has a unique digital signature A (the digital signature A is generated by hardware ID encryption, such as Figure 5 F88B6B0E10B7DAFD382FB28404D720DF in

[0076] The data forensics device takes evidence of each test material according to the demand to produce a result set file, and the result set file generates a digital signature B (the digital signature B is composed of file MD5 and time point, such as Figure 5 B699120BDF5FD5FA67AADDF87B1CC18E_20220103220706~8FD178ACA789CACC85F48F558202EBDE_20220324095638 in

[0077] Then the result set file generates the digital signature A of the data forensics device, the start of the evidence time, the evidence unit, the operator, the digital signature B and other items, forming an initial binding credential

[0078] Sb2, use the private key of the asymmetric encryption algorithm to encrypt the initial binding credential and chain it.

[0079] In a specific embodiment, an asymmetric encryption algorithm is used, each node has its own unique private key and paired public key, the binding information is encrypted using the private key, and the encrypted credentials are chained. The public key is disclosed, and other nodes can use the public key to verify the signature.

[0080] In a preferred embodiment, the result set file can be transferred to other devices for use, so after step Sb2, the following steps are also included:

[0081] Sb3, when the result set file is transferred to other devices, the other devices generate a unique digital signature C, combine the digital signature B, the digital signature C, and the transfer time, the operating unit, and the operator information into a transfer credential;

[0082] Sb4, using an asymmetric encryption algorithm to encrypt the transfer credentials using the private key for credential chaining.

[0083] In a specific embodiment, the other device also has a unique digital signature C (such as Figure 5 59B49A27A1078A9058ADE20727F7041E~20B5C1530E39589EDA26A4D8B448EFE9) in the

[0084] Figure 6 The flowchart of tracing the specified result set file according to one specific embodiment of the present application is shown, as shown in Figure 6 The result set file generates the corresponding initial binding credentials after being operated on node 1, and then generates the corresponding transfer credentials after being transferred to other devices through node 2.

[0085] According to a third aspect of the present application, a result set trust degree improvement system is proposed, which is built based on the result set trust degree improvement method of the first aspect of the present application. Figure 7 The block diagram of the result set trust degree improvement system according to an embodiment of the present application is shown, as shown in Figure 7 The system includes:

[0086] The data table generation module 1 is configured to splice the field contents of each data in the result set file during parsing, calculate the MD5 of each spliced data as a data HASH, and generate a plurality of data tables containing the data HASH, and the plurality of data tables constitute a database.

[0087] The TABLE information table generation module 2 is configured to calculate the table name MD5 of each data table as a table name HASH, and store the table name HASH to form a TABLE information table.

[0088] The DATABASE information table generation module 3 is configured to calculate the file MD5 of the database as the database file HASH, and store the database file HASH to form the DATABASE information table.

[0089] The update module 4 is configured to update the data table, the TABLE information table and the DATABASE information table into the result set file.

[0090] According to a fourth aspect of the present application, a result set supporting traceability system is provided, which is built based on the result set supporting traceability method according to the second aspect of the present application. Figure 8 A block diagram of the result set supporting traceability system according to an embodiment of the present application is shown in FIG. 1, which includes: Figure 8

[0091] The initial credential acquisition unit 5 is configured to input the sample file into the data forensics device, and the data forensics device generates a unique digital signature A. After the data forensics device takes evidence of each sample in the sample file, a result set file is generated, and a digital signature B is generated for the result set file. The initial binding credential is formed by combining the digital signature A, the digital signature B, the starting time of evidence taking, the evidence taking unit and the operator information.

[0092] The initial credential encryption unit 6 is configured to use a private key to encrypt the initial binding credential using an asymmetric encryption algorithm, and then chain the encrypted credential.

[0093] The flow credential acquisition unit 7 is configured to generate a unique digital signature C when the result set file is transferred to other devices, and combine the digital signature B, the digital signature C, the transfer time, the handling unit and the operator information to form the flow credential.

[0094] The flow credential encryption unit 8 is configured to use a private key to encrypt the flow credential using an asymmetric encryption algorithm, and then chain the encrypted credential.

[0095] According to a fifth aspect of the present application, a computer readable storage medium is provided, which stores a computer program. When the computer program is executed by a processor, the result set trustworthiness improvement method and the result set supporting traceability method according to the first aspect and the second aspect of the present application are implemented.

[0096] ​The application provides a result set trust degree improving method, a supporting traceability method and system, a field, a piece of data, a data table and a whole database file in a result set file are sequentially generated into HASH, and an interference factor is added to improve cracking difficulty, multiple tests are performed from fine granularity to coarse granularity, and the trust degree of the result set is improved. Moreover, the result set is combined with the technology of the block chain, the process of the result set from generation, use to archiving and warehousing is traced, the judicial effectiveness of the result set is improved, the error guidance of the result set error data on the event trend is avoided, the electronic data forensics technology is supplemented, the practicability is high, and the application value is high.

[0097] In the embodiments of the present application, it should be understood that the disclosed technical contents can be implemented in other ways. Among them, the above-mentioned device / system / method embodiment is only schematic, for example, the division of the unit can be a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed units can be indirect coupling or communication connection through some interfaces, units or modules, and can be electrical or other forms.

[0098] The unit described as a separate component can or can not be physically separated, and the component displayed as a unit can or can not be a physical unit, that is, it can be located in one place, or it can be distributed to multiple units. According to actual needs, part or all of the units can be selected to achieve the purpose of the embodiment scheme.

[0099] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0100] The integrated unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the methods described in the embodiments of the present application. The aforementioned storage medium includes: a U disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a mobile hard disk, a magnetic disk or an optical disk, and various media that can store program codes.

[0101] Obviously, those skilled in the art can make various modifications and changes to the embodiments of the present application without departing from the spirit and scope of the present application. In this way, if these modifications and changes are within the scope of the claims of the present application and their equivalents, the present application also aims to cover these modifications and changes. The word "comprises" does not exclude the presence of other elements or steps not listed in the claims. The simple fact that certain measures are described in mutually different dependent claims does not mean that the combination of these measures cannot be used to advantage. Any reference signs in the claims should not be considered as limiting the scope.

Claims

1. A method for improving the trustworthiness of a result set, characterized in that: Comprising the following steps: Sa1, in the process of parsing the result set file, the field content of each data is spliced, the MD5 of each data after splicing is calculated as data HASH, and a plurality of data tables containing the data HASH are generated correspondingly, and the plurality of data tables constitute a database; The calculation of the MD5 of each data after splicing is carried out in the parsing process of the result set file and / or after the parsing is completed; Sa2, calculate the table name MD5 of each data table as table name HASH, and store the table name HASH to form a TABLE information table; Sa3, calculate the file MD5 of the database as the database file HASH, and store the database file HASH to form a DATABASE information table; And Sa4, update the data table, the TABLE information table and the DATABASE information table to the result set file; In the process of generating the data HASH, the table name HASH and the database file HASH, an interference factor is added in the data after splicing, the table name of the data table and the file of the database, respectively.

2. The method of claim 1, wherein, The TABLE information table in step Sa2 also stores the number of data in each data table.

3. The method of claim 1, wherein, The DATABASE information table in step Sa3 also stores the number of file modifications of the database.

4. The method of claim 1, wherein, The DATABASE information table in step Sa3 also stores the file modification time of the database.

5. A provenance supporting method of a result set, for supporting provenance of the result set file according to any one of claims 1-4, characterized in that, Comprising the following steps: Sb1, the data of the sample file is connected to the data forensics equipment, the data forensics equipment generates a unique digital signature A, the data forensics equipment takes evidence of each sample in the sample file to produce the result set file, the result set file generates a digital signature B, and the digital signature A, the digital signature B and the starting time of evidence, the evidence unit, the operator information are combined into an initial binding credential; And Sb2, using asymmetric encryption algorithm, the private key is used to encrypt the initial binding credential and chain the encrypted credential; Sb3, when the result set file is transferred to other equipment, the other equipment generates a unique digital signature C, and the digital signature B, the digital signature C and the transfer time, the transfer unit, the operator information are combined into a transfer credential; And Sb4, using the asymmetric encryption algorithm, the private key is used to encrypt the transfer credential and chain the encrypted credential.

6. A system for boosting trustworthiness of a result set, the system comprising: Comprising: Data table generation module, configured to splice the field content of each data in the process of parsing the result set file, calculate the MD5 of each data after splicing as data HASH, and generate a plurality of data tables containing the data HASH correspondingly, and the plurality of data tables constitute a database; The calculation of the MD5 of each data after splicing is carried out in the parsing process of the result set file and / or after the parsing is completed; TABLE information table generation module, configured to calculate the table name MD5 of each data table as table name HASH, and store the table name HASH to form a TABLE information table; A DATABASE information table generating module is configured to calculate the MD5 of the database file as the database file HASH, and store the database file HASH to form the DATABASE information table. An updating module is configured to update the data table, the TABLE information table and the DATABASE information table into the result set file. During the generation of the data HASH, the table name HASH and the database file HASH, an interference factor is added into the spliced data, the table name of the data table and the file of the database respectively.

7. A provenance-enabled system of a result set, the system comprising: Comprise: An initial credential acquisition unit is configured to input a sample file into a data forensics device, the data forensics device generates a unique digital signature A, the data forensics device generates a result set file after forensics on each sample in the sample file, the result set file generates a digital signature B, and the digital signature A, the digital signature B, the starting time of forensics, the forensics unit and the operator information are combined into an initial binding credential; An initial credential encryption unit is configured to use a private key to encrypt the initial binding credential by using an asymmetric encryption algorithm, and chain the encrypted credential; A flow credential acquisition unit is configured to, when the result set file is transferred to other equipment, the other equipment generates a unique digital signature C, and the digital signature B, the digital signature C, the transfer time, the handling unit and the operator information are combined into a flow credential; A flow credential encryption unit is configured to use a private key to encrypt the flow credential by using the asymmetric encryption algorithm, and chain the encrypted credential. 8.A computer readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the method of any one of claims 1-5.

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