KR102013415B1 - System and method for verifying integrity of personal information - Google Patents

Abstract

The personal information access record integrity verification system and verification method, for the initial exchange of information, the integrated management server and the access record verification value storage server generates and transmits a secret key necessary to share each other's public key and derive a verification value. In order to generate the verification value, the integrated management server periodically collects all log data generated from the personal information processing system, extracts only the log data corresponding to the personal information access record from the collected log data, Generate the integrated verification value that can verify the individual verification values generated in the collection cycle as a single value, transfer the generated individual verification values and integration verification values to the access record verification value storage server, and for integrity verification, The management server generates individual verification values and integrated verification values by itself, and then checks received from the access record verification value storage server. When compared to the value, matching is characterized in that determination is made that the integrity.

Description

Personal information access record integrity verification system and verification method {SYSTEM AND METHOD FOR VERIFYING INTEGRITY OF PERSONAL INFORMATION}

The present invention relates to a personal information access record integrity verification system and verification method.

Various personal information is transmitted online. Such personal information needs to be protected, and various technologies for protecting such personal information have been proposed.

The technique disclosed in Patent Document 1 is an example of such a technique.

Public institutions and companies that provide services through personal information of customers operate an information system (hereinafter referred to as 'personal information processing system') to process personal information. Since personal information is information that can be recognized or easily combined with other information to recognize an individual, if the personal information is exposed, there is a threat that may invade the privacy of the individual. Public institutions and companies that provide services through personal information manage a large amount of personal information, so if an infringement occurs and personal information is leaked, the privacy of many people can be violated. In fact, a large number of accidents that caused a large amount of personal information leakage occurred between 2006 and 2015, which may threaten the privacy of individuals.

Therefore, the personal information processing system should protect the personal information stored in the personal information processing system from internal and external attacks and establish measures for follow-up management so that personal information is not exposed and personal privacy is infringed. To this end, the National Institute of Standards Technology (NIST) recommends that you maintain the information you need for system audit trails and review them in a consistent manner. In addition, in Korea, related laws such as the Personal Information Protection Act require access to the personal information processing system to collect and manage the history records using personal information (hereinafter referred to as “personal information access records”).

Personal information access records are used for the purpose of analyzing the causes of infringement through the audit trail of personal information infringement incidents such as illegal inquiry and misuse of personal information, and finding solutions. However, although personal information access records may be generated and managed in the format required by the law, such as software such as O / S, DBMS, etc. in the environment in which the personal information processing system is operated, and H / like firewalls. W equipment can also be distributed and created and managed in various formats by including its own log records (personal information access records) required by legislation.

As a result, it is stored in the form of log of different nature from the personal information access record required by the law. Therefore, when an infringement accident occurs in the personal information protection site, in order to analyze and respond to the cause of the accident, the attack technique, and the like, there is a difficulty of undergoing a separate integration and extraction procedure as shown in FIG. 2. Therefore, it is necessary to extract and manage only the personal information access records included in the log data generated by each log generation S / W and the device separately and to analyze the incidents quickly and accurately.

For the security of personal information access records, (1) a method using MAC, (2) a method using FssAgg authentication, and (3) a method using digital signature have been proposed.

Personal information access record records the actions such as inquiry and modification by accessing personal information and is included in the log data recorded for system management. Therefore, in order to prove the integrity of personal information access record, it must basically satisfy the security requirements of log system. The following security requirements are needed to establish an environment for managing personal information access records.

① Identify the point of attack

Since the log system records and manages the actions of system users and system events, the log system includes a sequential attack stage of the breach. Therefore, this information can be used to analyze the incident.

However, if an attacker attempts to forge or delete a log to remove the trace of his intrusion, it may not be possible to analyze the breach accurately and quickly, and the meaning of log analysis may disappear. Therefore, it is necessary to identify the point of attack that forgery or delete the log to distinguish the attacked log from the attacked log. Distinguishing them allows for faster and more accurate analysis of infringement incidents.

In the case of the FssAgg authentication scheme, when data is generated, an integrated verification value for integrity verification is generated, and the integration verification value is regenerated from the data stored during the integrity verification and compared with the previously generated integration verification value. As a result, forgery or deletion of log data can be detected. However, since the integrated verification value implies the entire data as one value, the attack on the log data can be detected, but it is not known at what time the attack occurred. Also, in the related research, in the proposed method using MAC and digital signature, when the data is generated, the individual verification values of the log data are generated by using the private key and the private key. Each individual verification value is regenerated to verify its integrity by comparing it with a previously generated verification value. In this case, if a forgery or deletion attack on log data occurs, it is possible to pinpoint when the attack occurred. However, the verification time is not only very long, but also inefficient because the task of generating the individual verification values for all data and comparing them with the previously generated verification values must be done during the integrity verification. Therefore, there is a need for a solution that can make up for both of these drawbacks.

② Forward security and flow security

The personal information processing system manages a large number of personal information and serves to serve customers. If the personal information processing system is attacked and the personal information is leaked, secondary damage may occur that infringes the privacy of the individual through the personal information. Therefore, it is important to prepare protection measures for the personal information processing system. However, inevitably, the attack on the personal information processing system is performed, and if the attacker manipulates the personal information access record and the verification value to prove the integrity of the personal information access record to remove the traces of his intrusion, It is difficult. Therefore, in case of attacker's intrusion, it should protect the integrity verification value to prevent forgery of the verification value before the intrusion time. This protection is called 'Forward Security' and claimed that M. Bellare and others should be able to protect the verification values of the log data created before the attack on the log system. Forward security generates a private key or a private key (Ki), which is used to generate individual verification values as different values for each log data (Li), as shown in FIG. It is the property that the next key can be derived from the key used to generate the, but the previous key cannot be deduced from the derived key.

Even if the attacker stole the key information at the time of attack, the attacker could not know the key to generate the previous verification value. In addition, since the key information is not known, the verification value for the log data cannot be generated and manipulated arbitrarily by an attacker. Therefore, it is possible to prevent forgery attack of log data generated before the attack time.

Even if the forward security is satisfied, it may be difficult to detect when an attack is performed that selectively deletes log data items or changes the order of log data. Therefore, it is necessary to prove the integrity of the sequential flow of log data. This protection measure is called 'stream security' and argued that not only should the log data generated before the attack by A. Attila et al. Be protected, but also the order of the log data. Flow security can be satisfied by giving dependencies with previously generated log data. In the FssAgg MAC authentication scheme, when generating an integrated verification value, FssAgg MAC authentication combines previously generated integration verification values with individual verification values of newly generated log data, and combines the new verification values with a hash function. This creates a dependency with previous log data. If you rearrange the order of the data, you can detect that the rearrangement attack on the log data occurred because the verification value generated at the time of log data generation and the newly generated verification value for integrity verification are different. have.

③ Detection of forgery and deletion of log data

To prove the integrity of log data, it must be possible to detect forgery or deletion attacks on the log data. In order to detect such an attack, many security logging schemes generate individual verification values such as MAC or signature values by using a secret key or a private key whenever log data is generated as shown in FIG. 4. In addition, we use a hash function to generate an integrated verification value so that we can verify it integrally.

Individual verification values can detect forgery and attack on each log data (Li). When each log data is generated, create a separate verification value using a secret key or private key, and if you want to verify the integrity of the log data, create a new one through the verification value generated when the data is generated and the stored log data. You can verify by comparing one verification value to see if it matches. If the previously generated verification value is the same as the newly created verification value, it means that the attack on the log data has not occurred. If the two values are different, it means that the attack on the log data has occurred. However, since the individual verification values only verify the integrity of each log data, it is difficult to detect when deleting the log data and a part of the corresponding individual verification values.

Integrated verification values can detect forgery and deletion attacks against each log data. When each log data (Li) is generated, the combined verification value is generated by combining the log data into one value and hashing the combined value. It uses the collision avoidance of the hash function to detect forgery of log data. In addition, when log data is deleted by combining log data, the combined value is changed, so the result value of the hash function is also different. Therefore, an attack in which log data is deleted can be detected by comparing the integrated verification value generated when the log data occurs with the integrated verification value generated after the deletion.

④ Consider data characteristics

Since log data is a record of system events and user actions, log data is continuously generated as the system operates. As a result, the amount of log data grows over time. Therefore, it is necessary to prepare a plan that considers the characteristics that log data is continuously generated and the amount of data is huge. Individual verification values can verify the integrity of each log data. However, because the amount of log data is huge, if all the verification values of each log data are managed, each individual verification value must be regenerated and compared when verifying the integrity of the data. In addition, the verification method for generating an electronic signature using a private key when generating an individual verification value has a longer operation time than the method for generating a MAC using a secret key, but is a key used when generating a verification value and when verifying. Is different, so security is high. Therefore, it is efficient to use the method considering the environment of the logging system where a large amount of data occurs.

In addition, there is an attribute stored according to the purpose of each log data. Among them, time information is included in log data because it is used as important information to analyze when an infringement incident on the system occurs. If this time information can be used to efficiently manage the verification value of the log data, the system environment can be more usefully constructed.

Patent Document 1: KR 10-2014-0038576 A (published: 2014.03.31.)

The problem to be solved by the present invention is to provide a personal information access record integrity verification system and verification method having satisfactory characteristics in terms of attack time identification, forward security and flow security, forgery and deletion attack detection, data consideration considerations will be.

The personal information access record integrity verification system according to the present invention is a personal information access record integrity verification system including a personal information processing system, an integrated management server, and a access record verification value storage server. The access record verification value storage server generates and transmits a secret key necessary to share each other's public key and derive a verification value, and to generate the verification value, the integrated management server stores all log data generated from the personal information processing system. After collecting periodically, only log data corresponding to personal information access record is extracted from the collected log data, and generate an integrated verification value that can verify individual verification values and individual verification values generated in one collection cycle as one value. And transmits the generated individual verification value and integrated verification value to the access record verification value storage server, and integrity For authentication, the integrated management server is characterized in that the determination is made that is, if matching integrity as compared with the verification value received from the respective self-verification value and then generates a verification value integration, connection history verification value storage server.

The personal information access record integrity verification method according to the present invention is a personal information access record integrity verification method using a personal information access record integrity verification system including a personal information processing system, an integrated management server, and a access record verification value storage server. In order to exchange information, the integrated management server and the access record verification value storage server share a public key with each other and generate and transmit a secret key necessary to derive a verification value; In order to generate the verification value, the integrated management server periodically collects all log data generated from the personal information processing system, extracts only log data corresponding to the personal information access record from the collected log data, and then collects individual verification values and one. A second step of generating an integrated verification value capable of verifying individual verification values generated in a cycle as one value and transmitting the generated individual verification values and the integration verification value to the access record verification value storage server; In order to verify the integrity, the integrated management server generates an individual verification value and an integrated verification value by itself, and compares the verification value received from the access record verification value storage server to determine that there is integrity if there is a match; It is characterized by including.

The personal information access record integrity verification system and verification method according to the present invention have satisfactory characteristics in view of attack time, forward security and flow security, forgery and deletion attack detection, and data consideration.

1 is a conceptual diagram of a personal information processing system for generating and managing logs in a distributed manner
2 is a flow chart of personal information infringement incident analysis
3 is a conceptual diagram for explaining the forward security
4 is a conceptual diagram illustrating generation of individual verification values and integrated verification values;
5 is a block diagram of a personal information access record integrity verification system according to the present invention
6 is a conceptual diagram for verifying the integrity of the personal information access record
7 is an initial information exchange procedure 1
Initial Information Exchange Procedure 2 of FIG. 8
9 is a procedure of generating a verification value of one collection period
10 is a verification value generation procedure
11 is a procedure when the storage period of the verification value expires
12 is a procedure for verifying integrity 1
13 is a procedure 2 during integrity verification

As the present invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

5 is a block diagram of a personal information access record integrity verification system according to the present invention.

The personal information access record integrity verification system according to the present invention includes a personal information processing system, an integrated management server, and a access record verification value storage server (third trust authority). In the following description, 'third trusted authority' is used as the same meaning as 'access record verification value storage server'.

In the case of integrated management of personal information access records, when an infringement accident occurs at the personal information protection site, it can quickly and accurately analyze and cope with the cause of the accident and the attack technique. However, as the personal information access record is integratedly managed, the personal information access record may be an attack target. Therefore, it is very important to prove the integrity that the personal information access record has not been forged, altered or deleted because it is necessary to protect the integrated personal information access record and it can be used as legal evidence. In the present invention, an integrated management server is operated to collect and manage personal information access records from various log generation S / W and devices in an environment in which existing personal information access records are distributed as shown in FIG. 5. In addition, a third trust organization (access record verification value storage server) is operated to protect the verification value from internal and external attacks on the personal information access record managed by the integrated management server. It is assumed here that the third party trusts is safe.

In order to verify the integrity of the personal information access record through the integrated management server and a third trusted authority, the personal information access records collected and extracted from the log generating S / W and the device are managed by the integrated management server as shown in FIG. The verification value for the information access record is generated and transmitted to the third trust authority. By managing the verification value generated by the third party as the personal information access record occurs, the integrated management server can safely store the verification value from internal and external attacks. In addition, public verification is also possible because the verification value is managed by a third party.

The integrated management server collects all log data including personal information access records from each log generating software and device. In addition, the legally required personal information access record is extracted from the log data and stored integrally. For this purpose, it is assumed in the present application that this process is repeated periodically. That is, it is assumed that personal information access records are periodically accumulated in the integrated management server. Whenever the personal information access record is collected integrally, the integrated management server generates a value for verifying this. In this case, since the verification value is a value for integrally verifying one collection cycle, one verification value is generated for each collection cycle. The third-party trust organization operates for the integrated management server of various organizations and enterprises and manages the verification values transmitted from the integrated management server.

When the integrated management server requests a verification value from a third trusted authority for integrity verification, the integrated management server transmits the verification value to the integrated management server. The verification value shall be kept for at least 6 months depending on the retention period of the personal information access records required by the law. The process of verifying the integrity of the personal information access record through the integrated management server and the third-party trust organization that plays the above roles can be described in three steps as follows.

① Initial Information Exchange

② Generation of verification value

③ Integrity Verification

(1) Initial Information Exchange

In the initial information exchange step, as shown in FIG. 7, a public key is shared between the integrated management server and a third trusted organization for secure information transfer, and a secret key necessary for deriving a verification value is generated and transmitted. For secure key exchange, it is assumed that the integrated management server and the third party trust each other.

The integrated management server and the third trust authority generate public key (P _B , P _C ) and private key (S _B , S _C ) pairs as shown in FIG. 8 to encrypt data transmitted between each other. Thereafter, the integrated management server transmits a message requesting a public key to a third trusted authority. The third trusted authority checks the public key request message received from the integrated management server and transmits its public key P _C to the integrated management server. The integrated management server checks the public key received from the third trusted authority and transmits its public key P _B. Through this process, the integrated management server and the third trusted authority can encrypt and transmit the data transmitted between each other by using the exchanged public key. After confirming that the public management server's public key (P _B ) has been received, the third-party trust organization may identify the initial secret key (K ₁ ) and the integrated management server required when generating the MAC, which is an individual verification value of the personal information access record. Sends a message requesting the integrated management server the ID, which can be an identifier. Receiving this message, the integrated management server generates a random key for generating the first individual verification value as a random number, and encrypts it with a public key of a third-party trust authority with its identifier. This value is then digitally signed with the private key of the integrated management server and transmitted to a third trusted authority. Digital signatures cannot be forged because only the signer can generate a signature value, and the recipient of the value can verify the signature by using the signer's public key. In addition, it can prove that the message to be sent has not changed between transmissions, and also includes a non-repudiation function, so that the message can be delivered more securely.

(2) Generation of verification value

The integrated management server periodically collects all log data generated from the log generation S / W and the device, and extracts and manages the personal information access records included in the log data. At this time, the log data collection occurs periodically, and the verification value is also generated for each log data collection cycle.

As shown in FIG. 9, the log generating S / W and the device transmit all log data generated by the log to the integrated management server at regular intervals. The integrated management server extracts only the log data corresponding to the personal information access record from the received log data and stores it in one repository so that it can be integratedly managed. When the personal information access record is extracted and integrated, the verification value for this data is generated. The verification value, like the FssAgg MAC authentication scheme, generates MAC, which is an individual verification value for each personal information access record. Although digital signatures can be used as a method of generating individual verification values, digital signatures are inefficient in an environment where a large amount of data is generated because the processing speed is slower than that of MACs when verification values are generated through digital signatures. Therefore, individual verification values are generated using MAC. The secret key used to generate the MAC uses a different secret key for each access record while updating the secret key generated in the initial information exchange step with the hash chain technique. In addition, the secret key used to generate the individual verification value is updated with the secret key for generating the next individual verification value and deleted to prevent exposure of the previous secret key. In this case, it satisfies the forward security of the verification value, and even if an attack on the integrated management server occurs, the secret key before the attack cannot be inferred. The method of deriving the individual verification value using the secret key and MAC to which the hash chain that satisfies the forward security is as follows.

K _i : i-th secret key, K ₁ : Random, h (x): One-way hash function,

R _i : i'th personal information access record, MAC _ki (x): MAC function

Z _i : i th individual verification value

K _i = h ^i-1 (SEED), Zi = MAC _ki (Ri)

After generating the individual verification values, the verification values are generated by integrating the individual verification values generated in one collection cycle to be verified as one value. The integrated verification value is a result obtained by hashing the previously generated integration verification value and the individual verification value. When a new integration verification value is generated, the previously generated integration verification value is deleted. The generated integrated verification value can detect forgery / falsification and deletion attacks on personal information access records during one collection cycle. In addition, it is possible to verify the integrity of the personal information access record generated for each collection cycle. In other words, since the integrity can be verified for each collection cycle, it is possible to identify which collection cycle has occurred. Thereafter, the integrated management server that generates the integrated verification value encrypts the integration verification value, an ID for identifying itself, and a value of TAG with a public key of a third trusted authority received in the initial information exchange step. The ID and TAG are digitally signed with their private key and transmitted to the third-party trust authority along with the encrypted value. Over time, the integration verification values are generated for each collection cycle, so the number of integration verification values to manage increases.

In this case, if the attacker who invades the integrated management server makes an attack that rearranges the order of access records of personal information organized by collection cycle, integrity verification cannot be performed properly. Therefore, it must satisfy the flow security which is the integrity of the order of the integration verification values. Therefore, TAG is used to satisfy the flow security of the integrated verification value generated according to the collection period of the personal information access record as shown in FIG.

The TAG is a result of hashing the TAG generated in the previous cycle and the integrated verification value generated in the current cycle. If the value is generated in this way, it is possible to detect the rearrangement attack because the TAG value is changed if the sequence of the personal information access records is rearranged when the integrity verification value is configured in a chain form to verify the integrity. The TAG can also verify the integrity of the integration verification value. Therefore, an attack for deleting the personal information access record corresponding to one collection period can be detected. The following is the method to derive the integrated verification value and TAG through individual verification values, encrypt them, and digitally sign them.

B: integrated management server, C: third party

Z _i : i-th individual verification value, H _i : i-th integrated verification value,

h (x): One-way hash function, P _x : Public key of _x , S _x : Private key of x,

Sign _Sx (): Digital signature with x's private key, E _Px (): Encryption with x's public key

TAG: Flow security value of the integrated verification value, ID: Integrated management server identifier

H _i = h (Z _i ∥ H _{i -1} )

TAG _i = h (integrated verification value of previous acquisition cycle TAG ∥ current acquisition cycle),

Encryption of ID and Verification Value = Epc (ID ∥ Hi ∥ TAG)

Digital signature of ID and verification value = SignSB (ID ∥ Hi ∥ TAG)

The third trusted authority receives the value received from the integrated management server, checks the signature value with the public key of the integrated management server, and decrypts it with its private key. Then, in order to check whether the value transmitted from the integrated management server is the correct value, a new TAG is generated and compared with the TAG transmitted in the current cycle through the TAG of the previous collection cycle and the integrated verification value received in the current collection cycle. If the correct value is correct, save the integration verification value and the TAG and discard the TAG from the previous collection cycle. The integrated verification value generated for each collection cycle is managed by a third party for at least six months, which is a legal obligation. In addition, since the third-party trust authority manages the integrated verification value without having to manage the individual verification values of all personal information access records, it uses less storage and reduces the load on the communication.

The third-party trust organization stores the integrated verification value, TAG, and initial secret key received from the integrated management server for one year in six months, satisfying the requirements of the law and considering the storage limits. That is, as shown in FIG. 11, the integrated verification value and the TAG generated for 6 months from the initial secret key generation time are called one set A, and the initial secret key and the integrated verification value generated for the next 6 months, and the set of TAGs. If we assume that B is the expiration period of the set B after 6 months, delete the previously stored set A, and maintain B.

When the storage period expires after six months, the integrated management server sends an expiration request message with its identifier to a third party. After that, the initial secret key (K _{a '} ) of the set C is randomly generated and transmitted by applying encryption and digital signature. The third-party trust authority confirms the message through signature verification and decryption of the message, confirms the identifier of the integrated management server, and deletes the A set of the integrated management server. In addition, the C set including the new initial secret key received is generated, and then the integrated verification value and TAG received from the integrated management server are stored. As such, the initial secret key, the integrated verification value, and the TAG are stored for one year for six months, and the initial secret key generated every six months is always generated through random numbers. In other words, the initial secret key included in each set is unrelated to each other.

(3) integrity verification

The integrity verification step is a step of verifying that the personal information access record stored in the integrated management server has not been changed. That is, it is determined whether the personal information access record has been attacked, forged or deleted. In this step, the verification management needs to be performed when necessary, so that the subject performing verification is the integrated management server. When the integrity verification is to be performed as shown in FIGS. 12 and 13, the integrated management server is a third trusted authority. Sends a message requesting an ID and a verification value to identify the ID.

The third-party trust authority receives this message and checks the ID, the identifier of the integrated management server, and integrates the verification value (H ₁ ~ H _x ), the initial secret key (K ₁ ), and the TAG of the corresponding integrated management server. Encrypt with the server's public key. In addition, the verification value (H ₁ ~ H _x ), the initial secret key (K ₁ ), TAG is digitally signed with its own private key and transmitted to the integrated management server with the result of encryption. The integrated management server checks the digital signature of the received message with the public key of a third-party trust authority, and decrypts the encrypted message with its own private key to temporarily store it. Then, the integrated verification value and TAG of the personal information access record stored by the user are regenerated according to the procedure of the verification value generation step (H ' ₁ , ..., H' _x , TAG ' _x ). The integrity is then verified by comparing the verification values received from the third-party trust organization to see if they match. If the regenerated verification value does not match the verification value received from a third party, it means that the privacy record has been forged, tampered with, or deleted, and if so, no attack on the privacy record has occurred. Means that.

The personal information access record integrity verification system according to the present invention includes a personal information processing system, an integrated management server, and a access record verification value storage server.

For the initial exchange of information, the integrated management server and the access record verification value storage server share the public key with each other and generate and transmit a secret key necessary to derive the verification value.

In order to generate the verification value, the integrated management server periodically collects all log data generated from the personal information processing system, extracts only log data corresponding to the personal information access record from the collected log data, and then collects individual verification values and one. An integrated verification value for verifying the individual verification values generated in the cycle as one value is generated, and the generated individual verification values and the integration verification value are transmitted to the access record verification value storage server.

For integrity verification, the integrated management server generates individual verification values and integration verification values by itself, compares the verification values received from the access record verification value storage server, and determines that there is integrity.

The personal information access record integrity verification method according to the present invention includes the following three steps.

(1) The first step for the initial management of information exchange, the integrated management server and the access record verification value storage server generate and transmit a secret key necessary for sharing the public key with each other and deriving the verification value.

(2) To generate the verification value, the integrated management server periodically collects all log data generated from the personal information processing system, extracts only the log data corresponding to the personal information access record from the collected log data, and then checks the individual verification values. And a second step of generating an integrated verification value for verifying the individual verification values generated in one collection cycle as one value and transmitting the generated individual verification values and the integration verification value to the access record verification value storage server.

(3) For integrity verification, the integrated management server generates the individual verification value and the integrated verification value by itself, and compares the verification value received from the access record verification value storage server to determine that there is integrity if there is a third match. step

The characteristics of the personal information access record integrity verification system and verification method according to the present invention are evaluated as follows.

① Identify the point of attack

In this application, the integrity verification value is generated by applying the FssAgg MAC authentication technique to verify the integrity of the personal information access record. At this time, one verification value is generated for each collection period of the personal information access record, and this value verifies the integrity of the personal information access record generated in each collection period. Therefore, this verification value can detect in which collection cycle the forgery, alteration or deletion of personal information access record occurred. That is, the attack time can be identified by comparing the verification value generated in each collection cycle with the newly generated verification value in the integrity verification step.

② Forward security and flow security

Forward security is a property that makes it impossible to infer the secret key before the attack even if the secret key used to generate the verification value after the system is compromised is exposed. Since the private key used cannot be inferred, the verification value generated before the attack cannot be tampered with. Therefore, the verification value before a certain point in time can be protected. In order to satisfy these requirements, the present application performs key evolution through the hash chain mechanism to use different secret keys when generating MACs for each personal information access record. The next secret key can be derived, but forward security is satisfied by preventing the previous secret key from being inferred by the next secret key.

Stream Security is a way to protect the integrity of the order of data and can detect attacks that delete some of the data or reorder the data. This flow security can be satisfied by giving dependencies between the collected data. In the present invention, a verification value is generated using the FssAgg MAC authentication technique for the personal information access records collected in one collection cycle. When generating verification values using the FssAgg MAC authentication technique, each time a separate verification value of the generated data is generated, the new integration verification value is calculated using the individual verification value and the previously generated integration verification value, so the old data is deleted or ordered. When is changed, it can be detected. In addition, since the TAG is generated through the integrated verification values generated for each collection cycle, an attack that deletes all the personal information access records generated in one collection cycle or rearranges the order of the integrated verification values can be detected.

③ Detection of forgery, forgery and deletion

The system that needs to manage the access record needs to protect the data because the access record is used to analyze the infringement incident. Therefore, the system that manages personal information access records should be able to detect attacks in which personal information access records are forged or altered or some data is deleted. To this end, a value that can verify the integrity of each collection cycle is generated and transmitted to a third-party trust institution to protect it from external and internal attacks. In the case of integrity verification, a new verification value is generated from the stored personal information access record and compared with the verification value received from a third-party trust organization to check whether it matches. If the two values are the same, the attack on the personal information access record has not been made. If the two values are different, the attack on the personal information access record has occurred.

④ Consider data characteristics

Log data is a record of system events, user actions, and so on, and data is continuously generated. The personal information access record is the information included in the log data and thus retains the characteristics of the log data. Therefore, it should be possible to efficiently verify the integrity of access records of personal information generated in a large amount. To this end, a value that can verify the integrity of a large amount of personal information access records is generated as one value per collection cycle. In the integrity verification, the integrity of the personal information access record is verified for each period by comparing only the verification values generated for each period without comparing the integrity of each personal information access record. Therefore, the load on the system side can be reduced.

Except for the proposed method using the electronic signature, the hash chain mechanism is used for the key evolution as the method used in this study. In addition, the method using the FssAgg authentication technique verifies the integrity of all log data with a single verification value, so that a forgery, forgery, or deletion of the data can be detected, but the timing of the attack cannot be determined. However, in the proposed method using MAC and the electronic signature, the verification method corresponding to each log data is generated and verified by comparing these values during integrity verification. Therefore, when the log data is attacked can be accurately identified. have. In the proposed method using MAC and the proposed method using FssAgg authentication, a method that can guarantee the integrity of the data flow by giving dependencies between data when generating verification values is used. However, in the proposed method using digital signature, flow security is not satisfied because there is no such process.

In addition, all of the existing proposed methods suggest ways to protect log data, and can detect forgery, forgery and deletion of log data. However, in the proposed method using MAC, the attack that deletes a partial set of the last part of the log data cannot be detected. In the proposed method using the MAC and the electronic method using the digital signature, the verification value for each log data is generated and the newly generated verification value and the previously generated verification value are compared one by one. The load is very large. Therefore, it is not suitable for use in an environment where a large amount of log data is generated. On the other hand, in the proposed method using FssAgg authentication, since integrity verification of all log data is performed through one integrated value, the system load is not generated during integrity verification.

Claims (2)

A personal information access record integrity verification system including a personal information processing system, integrated management server, and access record verification value storage server,
For the initial exchange of information, the integrated management server and the access record verification value storage server share the public key with each other and generate and transmit a secret key necessary to derive the verification value.
In order to generate the verification value, the integrated management server periodically collects all log data generated from the personal information processing system, extracts only log data corresponding to the personal information access record from the collected log data, and then collects individual verification values and one. Create an integrated verification value that can verify the individual verification values generated in the cycle as a single value, and transmit the generated individual verification values and integration verification values to the access record verification value storage server,
For integrity verification, the integrated management server generates individual verification values and integration verification values by itself, compares the verification values received from the access record verification value storage server, and determines that there is integrity if they match,
When generating the individual verification values, the individual verification values are generated using the MAC, and the secret key used when generating the MAC is updated for each personal information access record while updating the secret key generated in the initial information exchange step with the hash chain technique. Using a different secret key, the secret key used to generate the individual verification values is updated with the secret key to generate the next individual verification value and deleted to prevent exposure of the previous secret key,
After generating the individual verification values, the verification values are generated by integrating the individual verification values generated in one collection cycle into one value, and the integrated verification values are integrated with the previously generated verification verification values and the individual verification values. Personal information access record integrity verification system, characterized in that for generating a new integrated verification value by hashing the result generated by deleting the previously generated integration verification value.
As a personal information access record integrity verification method using a personal information access record integrity verification system including a personal information processing system, integrated management server, access record verification value storage server,
For the initial exchange of information, the integrated management server and the access record verification value storage server is a first step of generating and transmitting a secret key necessary to share each other's public key and derive a verification value;
In order to generate the verification value, the integrated management server periodically collects all log data generated from the personal information processing system, extracts only log data corresponding to the personal information access record from the collected log data, and then collects individual verification values and one. A second step of generating an integrated verification value capable of verifying individual verification values generated in a cycle as one value and transmitting the generated individual verification values and the integration verification value to the access record verification value storage server;
In order to verify the integrity, the integrated management server generates an individual verification value and an integrated verification value by itself, and compares the verification value received from the access record verification value storage server to determine that there is integrity if there is a match;
Including,
When generating the individual verification values, the individual verification values are generated using the MAC, and the secret key used when generating the MAC is updated for each personal information access record while updating the secret key generated in the initial information exchange step with the hash chain technique. Using a different secret key, the secret key used to generate the individual verification values is updated with the secret key to generate the next individual verification value and deleted to prevent exposure of the previous secret key,
After generating the individual verification values, the verification values are generated by integrating the individual verification values generated in one collection cycle into one value, and the integrated verification values are integrated with the previously generated verification verification values and the individual verification values. And generating a new integrated verification value using the result obtained by hashing, and deleting the previously generated integration verification value.

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