KR102605087B1 - System and method for sharing patient's medical data in medical cloud environment - Google Patents

Abstract

The present invention discloses a system and method for sharing patient medical data in a medical cloud environment. A system for sharing patient medical data in a medical cloud environment according to one aspect of the present invention includes a tracking authority server that receives user registration from users who will use the medical cloud and grants anonymous ID values to users who use the cloud; an attribute management server that manages the attributes of users using the medical cloud and generates secret keys corresponding to the attributes; and a medical cloud server that stores and manages data, performs user access control and partial decryption of ciphertext.

Description

System and method for sharing patient's medical data in medical cloud environment}

The present invention relates to a system and method for sharing patient medical data in a medical cloud environment, and more specifically, to a system and method for sharing patient medical data in a medical cloud environment that can prevent key abuse through traceability.

Cloud computing has become very popular and allows users to safely store and share data. Accordingly, cloud environments can be serviced in all fields, including B2C, enterprise fields, public fields, IoT services, etc.

Recently, with the combination of IoT and the cloud, patient data is collected through wearables through IoMT (Internet of Medical Things) in the medical field, stored in hospitals, and doctors or nurses can remotely monitor it to check the patient's health status. You can. In an IoMT environment, patients save their medical data (vital signals) on their smartphones through their healthcare wearables and transmit them to the hospital cloud server, where doctors or nurses in the patient's department can remotely access the patient's data. It can be monitored. After examining the patient's medical data, the doctor in charge transmits the prescription data to the cloud server, allowing the patient to check the prescription results for his or her medical data through a smart device. Therefore, through IoMT, data can be shared between patients and departments within the hospital, which can improve the quality of life of patients and medical staff.

However, various security threats may occur in the cloud in an IoMT environment. For example, users must use the cloud of a cloud service provider. Data stored in the cloud is safe from external threats, but the user's privacy may be violated because the cloud service provider has access to the data. In particular, data stored in a medical cloud environment is quite sensitive because it is the patient's medical data.

Therefore, research is needed to protect patients' medical data from security threats and safely store and share data in a medical cloud environment (IoMT).

Korean Patent Publication No. 2014-0042388 (published on April 7, 2014)

The present invention was proposed to solve the above problems, and provides an attribute-based data sharing system with key abuse prevention and verifiable outsourcing in a medical cloud environment, so that when a key is leaked, the user who was issued the key can be tracked. The purpose is to provide a system and method for sharing patient medical data in a medical cloud environment that can prevent key abuse in advance and allow users to verify whether the message was uploaded by the data owner through verification when obtaining the message.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by an embodiment of the present invention. In addition, it will be readily apparent that the objects and advantages of the present invention can be realized by means and combinations thereof as indicated in the claims.

In order to achieve the above object, a patient's medical data sharing system in a medical cloud environment according to an aspect of the present invention receives user registration from a user who will use the medical cloud and grants an anonymous ID value to the user who uses the cloud. a tracking authority server; an attribute management server that manages the attributes of users using the medical cloud and generates secret keys corresponding to the attributes; and a medical cloud server that stores and manages data, performs user access control and partial decryption of ciphertext.

The attribute management server registers user attribute information based on the anonymous ID value granted by the tracking authority server from the user, generates public parameters and a master key, and generates a user secret key using the registered user attribute information. And, public parameters and user secret keys are provided to the data user terminal, and the public parameters are transmitted to the data owner terminal of the data owner who registered the data.

The medical cloud server receives and stores the encrypted text from the data owner terminal, registers the encrypted text, receives a token from the data user terminal, partially decrypts the encrypted text, and transmits the partially decrypted encrypted text to the data user terminal to perform final decryption. It is characterized by verifying the obtained message and ensuring the integrity of the data.

The medical cloud server includes a storage server that stores and manages encrypted text; and an outsourcing server that manages user access and performs partial decryption.

In order to achieve the above object, a data sharing method in a patient's medical data sharing system in a medical cloud environment according to another aspect of the present invention includes a tracking authority server receiving user registration from a user who will use the medical cloud, and Granting an anonymous ID value to the user; A property management server managing the properties of a user using the medical cloud and generating a secret key corresponding to the properties; And a step of the medical cloud server storing and managing data, performing user access control and partial decryption of the ciphertext.

The step of the attribute management server managing the attributes of a user using the medical cloud and generating a secret key corresponding to the attribute includes registering user attribute information based on an anonymous ID value given by the user from the tracking authority server. Receiving stage; generating public parameters and a master key, and generating a user secret key using the registered user attribute information; And providing public parameters and user secret keys to the data user terminal, and transmitting the public parameters to the data owner terminal of the data owner who registered the data.

The steps of the medical cloud server storing and managing data, controlling user access, and partially decrypting the encrypted text include: receiving the encrypted text from the data owner terminal, storing the encrypted text, and registering the encrypted text; Receiving a token from a data user terminal and partially decrypting the ciphertext; And transmitting the partially decrypted ciphertext to the data user terminal to verify the message obtained after performing the final decryption.

A recording medium according to another aspect of the present invention for achieving the above object is a computer-readable recording medium on which a computer program is recorded for performing a data sharing method.

According to one aspect of the present invention, the confidentiality of data stored in the medical cloud is guaranteed and access by third parties without access rights is not possible, thereby improving the security of the patient's medical data.

In addition, since traceability is provided to confirm the identity of the user who initially issued and leaked the key through the distributed secret key, abuse of the key can be prevented in advance.

In addition, since the secret key is issued by the attribute management server through the user's anonymous ID value, it is possible to provide the user's anonymity.

The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below. .

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention along with specific details for carrying out the invention. Therefore, the present invention is shown in such drawings. The interpretation should not be limited to only the stated matters.
1 is a schematic configuration diagram of a patient's medical data sharing system in a medical cloud environment according to an embodiment of the present invention;
Figure 2 is a schematic flowchart of a data sharing method in a medical cloud environment according to an embodiment of the present invention;
3 is a schematic flowchart of the data encryption process according to an embodiment of the present invention;
Figure 4 is a schematic flowchart of a data access method and data decoding process of a data user according to an embodiment of the present invention;
Figure 5 is an example illustrating the flow of the process of confirming the identity of the user who first received the secret key from the attribute management server through the distributed secret key according to an embodiment of the present invention.

The above-described purpose, features and advantages will become clearer through the following detailed description in conjunction with the accompanying drawings, and accordingly, those skilled in the art will be able to easily implement the technical idea of the present invention. There will be. Additionally, in describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the attached drawings.

Throughout the specification, when it is said that a part “includes” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary. In addition, “…” stated in the specification. Terms such as “unit” refer to a unit that processes at least one function or operation, which may be implemented as hardware, software, or a combination of hardware and software.

For safe data storage and data sharing in a cloud environment, the security of stored data is most important. Additionally, access control technology and user authentication technology are needed to access encrypted data. One of these technologies is CP-ABE (ciphertext policy-attribute-based encryption), a type of attribute-based encryption. The CP-ABE method is an encryption technology suitable for multiple users to access encrypted data stored on a server, and various CP-ABE-based access control techniques have been studied to date. However, existing CP-ABE-based access control techniques are vulnerable to various security threats. In particular, in the CP-ABE data sharing system according to the prior art, the attribute management server cannot identify the user who issued the secret key. Therefore, users can leak private keys for their own benefit, and the user cannot be traced later. For example, if a doctor provides another user with a secret key to access the medical cloud for malicious purposes for his or her own benefit, the other user can access the medical cloud environment through the secret key received from the doctor. If the secret key sent to another person is wrong and you want to track the user (doctor) who issued the secret key, the user who issued the secret key cannot be known because the secret key does not contain information about the user who issued it. This is a characteristic that can occur due to the use of CP-ABE. To solve this problem, when a property management agency that verifies properties and issues keys issues a key for each user, it issues the user's ID value or user signature value as a parameter of the key. In the future, if there is a problem with the key, research is underway to track the user through the ID value of the user who first issued the key value or the user signature value of the key parameter. However, the user's information may be exposed to the property agency server, which may infringe on the user's personal information. Above all, attribute-based encryption is characterized by not having to reveal the identities of multiple participants because it accesses the user's attributes. Therefore, if the user ID value is managed in the attribute management server (AA), anonymity of users using the cloud is not provided.

In order to solve these problems according to the prior art, a system and method for safely sharing a patient's medical data in a medical cloud environment will be described with reference to FIGS. 1 to 5.

Figure 1 is a schematic configuration diagram of a patient's medical data sharing system in a medical cloud environment according to an embodiment of the present invention.

Before explaining the embodiments of the present invention, the symbols used in the following content are defined as follows.

Attribute Authority (AA): A third-party organization that manages user attributes, attribute management server

: Third party organization that can track users, tracking authority server

: Server that stores and manages data, medical cloud server

: Outsourcing server that manages user access control and performs partial decryption

: Master key (private key) held by each organization

: TA’s public key, private key pair

: AA public key, private key pair

: Public parameters and master key used for attribute-based encryption in the cloud

SK: User secret key (ciphertext decryption key)

UTR: Parameter (value) for user tracking

: User real ID, user-generated ID

: User Anonymous ID

: Each user attribute data, attribute data set

: Access policy or Access Structure

: Multi-values for each attribute

: Token for accessing the cloud

: Ciphertext that hides the encryption key value based on attributes, full ciphertext

C: Cipher text conversion value generated after partial decryption

T: timestamp

Referring to FIG. 1, the patient's medical data sharing system in the medical cloud environment according to this embodiment includes a tracking authority server 100, an attribute management server 200, and a medical cloud server 300.

The tracking authority server 100 receives user registration from users who will use the medical cloud and grants anonymous ID values to users who use the cloud.

The attribute management server 200 manages the attributes of users using the medical cloud and generates secret keys corresponding to the attributes.

The attribute management server 200 receives user attribute information based on the anonymous ID value granted by the tracking authority server 100 from the user, generates public parameters and a master key, and uses the registered user attribute information to create a user secret. A key is generated, public parameters and user secret keys are provided to the data user terminal 410, and the public parameters are transmitted to the data owner terminal of the data owner who registered the data.

The medical cloud server 300 stores and manages data, performs user access control and partial decryption of ciphertext.

The medical cloud server 300 receives and stores the encrypted text from the data owner terminal, registers the encrypted text, receives a token from the data user terminal 410, partially decrypts the encrypted text, and sends the partially decrypted encrypted text to the data user terminal 410. ) and verifies the message obtained after final decryption to ensure the integrity of the data.

Meanwhile, the medical cloud server 300 includes a storage server 310 that stores and manages ciphertext, and an outsourcing server 330 that manages user access and performs partial decryption.

FIG. 2 is a schematic flowchart of a data sharing method in a medical cloud environment according to an embodiment of the present invention, FIG. 3 is a schematic flowchart of a data encryption process according to an embodiment of the present invention, and FIG. 4 is an implementation of the present invention. Figure 5 is a schematic flowchart of a data access method and data decryption process of a data user according to an example, showing the user who was first issued a secret key from the attribute management server 200 through a distributed secret key according to an embodiment of the present invention. This is an example showing the flow of the process of tracking and verifying identity.

Before explaining the present invention, the following is assumed.

Initially, the tracking authority server 100 and the attribute management server 200 define two large prime numbers and an elliptic curve due to security parameters as follows.

[Equation 1]

The public key and private key of the tracking authority server 100 are , , the public key and private key of the attribute management server 200 are , It can be expressed as

The property management server 200 issues a key after verifying user properties. At this time, part of the user information value is is shared on the outsourcing server 330.

The property universal set is . Each attribute is multi-valued has, and as a set It can be expressed as

In more detail, Figure 2 shows the user registration and anonymous ID value issuance process in the tracking authority server 100 and the attribute registration process in the attribute management server 200 (S210) (S220).

In the user registration and anonymous ID issuance step, the user registers with the tracking authority server 100 using the data user terminal 410 and then receives an anonymous ID value. More specifically, the data user terminal 410 sends a registration message to the tracking authority server 100 with its unique identifier value and ID value. Send to request registration. The tracking authority server 100 uses the user's unique identifier value after confirmation Calculate . Afterwards, the user anonymous ID value is generated and transmitted to the data user terminal 410.

[Equation 2]

In the user attribute registration and user secret key generation step, when the data user terminal 410 registers user information and attributes with an anonymous ID in the attribute management server 200, the attribute management server 200 provides a secret key (ciphertext) corresponding to the attribute. A decryption key) is generated and transmitted to the data user terminal 410 (S230). More specifically, the data user terminal 410 is anonymous and transmits its properties to the property management server 200. The attribute management server 200 generates public parameters and/or master keys for the data owner terminal 430 and the data user terminal 410 through a setup process. At this time, the setup process is as shown in Equation 3 below.

[Equation 3]

The prime number of the bilinear mapping group G is p, and the random generator is Created with .

Afterwards, the attribute management server 200 receives the anonymous data transmitted from the user terminal 410. , property , perform the key generation process with the master key to obtain the secret key is generated and transmitted to an anonymous user terminal (data user terminal 410 and/or data owner terminal 430) (S240).

[Equation 4]

Random number ,

(number of each attribute), ( is a random value given for each attribute)

Afterwards, the property management server 200 sends some of the information values of the data user terminal 410 to the outsourcing server 330. Share.

Referring to FIG. 3, in the data encryption step, the data owner terminal 430 receives the information from the attribute management server 200. The data is encrypted by creating an access structure with the attributes of the data owner terminal 430 that wants to access its data, and transmitted to the storage server 310 of the medical cloud for storage (S310), (S320) (S330). More specifically, the data owner terminal 430 creates an access structure based on the attributes of users who can access their data within the medical cloud environment. Afterwards, the multi-values of the attributes specified in the access structure are calculated, and the key that encrypted the message with the symmetric key is encrypted to generate the ciphertext CT. Afterwards, the ciphertext CT' is constructed with the verification key value VK for the CS and KEY that encrypted the message. By calculating the values calculated for each attribute in the ciphertext CT as one, the size of the ciphertext can be reduced, and previously wasted cloud storage space can be used efficiently.

[Equation 5]

Multi-values for each attribute

access structure ,

(Random value generation)

if This side Calculate .

if This side Calculate .

,

Afterwards, the storage server 310 stores the received ciphertext.

Referring to FIG. 4, in the data access step, the data user terminal 410 generates a token (TK) through information received from the attribute management server 200 to access cloud storage. More specifically, the data user terminal 410 receives the secret key transmitted through the attribute management server 200. at Create a token (TK) to access the cloud. after, When access to the cloud is requested through the outsourcing server 330, some of the user information values shared from the property management server 200 Through of value is verified to determine that the user is a legitimate user (S410).

[Equation 6]

Afterwards, the outsourcing server 330 provides information about the user. Since the value is known, the user is verified by performing a verification process. Once the user is verified as a legitimate user, the user's desired ciphertext is requested from the storage, and partial decryption is performed by calculating and comparing the access structure specified in the ciphertext and the user attribute value (S420) . In the ciphertext decryption step, the outsourcing server 330, which first receives the ciphertext, compares the attribute values specified in the ciphertext that the user wants to access with the user attribute values, and if they match, performs a partial decryption step to obtain the ciphertext conversion value. Extract .

Afterwards, the data user terminal 410 receives the ciphertext conversion value from the outsourcing server 330. and ciphertext is transmitted, and the secret key held by the data user terminal 410 is Perform final decryption to obtain the key that encrypted the message (S430). The data user terminal 410 decrypts the message using the obtained key to obtain the message, performs a verification process, and confirms whether the data was uploaded by the data owner terminal 430 (S440). More specifically, the outsourcing server 330 performs partial decryption (Decrypt1) to obtain the ciphertext conversion value. After extracting, the outsourcing server 330 sends the ciphertext to the data user terminal 410. and transmit.

[Equation 7]

Afterwards, the data user terminal 410 receives the data from the outsourcing server 330. cast , , By performing the final decryption (Decrypt2), the key KEY that can decrypt the message is extracted. After the ciphertext Decode and obtain the message.

[Equation 8]

after, class as create an existing A verification process is performed and if they match, the integrity of the data owner's message is guaranteed.

[Equation 9]

Referring to Figure 5, the secret key In case of spill The step of tracking the user (data user terminal 410) who was first issued is intended to prevent an unregistered third party from receiving a key from someone and accessing the cloud. At this time, the investigative agency The process by which it is distributed is unknown, but it was first distributed to the property management server 200. The identity process of the user (data user terminal 410) who issued and distributed can be known through the tracking process. here, Proceed to the next step assuming that has been distributed. More specifically, the attribute management server 200 determines the parameters of the distributed key. After verifying the user anonymous ID value is extracted and sent to the tracking authority server (100), which is a tracking agency. Transmit (S510) (S520).

[Equation 10]

(Verification completed)

Afterwards, the tracking authority server 100 determines the user anonymous ID value. After receiving, the corresponding unique ID value Extract. after As a result, the identity of the user who issued the key is confirmed (S530).

[Equation 11]

Methods according to embodiments of the present invention may be implemented as applications or in the form of program instructions that can be executed through various computer components and recorded on a computer-readable recording medium. The computer-readable recording medium may include program instructions, data files, data structures, etc., singly or in combination. The program instructions recorded on the computer-readable recording medium may be those specifically designed and configured for the present invention, or may be known and usable by those skilled in the computer software field. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magneto-optical media such as floptical disks. media) and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. Examples of program instructions include not only machine language code such as that created by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules to perform processing according to the invention and vice versa.

While this specification includes many features, such features should not be construed as limiting the scope of the invention or the scope of the claims. Additionally, features described in individual embodiments of this specification may be implemented in combination in a single embodiment. Conversely, various features described in a single embodiment herein may be implemented individually or in combination as appropriate in various embodiments.

Although operations in the drawings are described in a particular order, it should not be understood that such operations are performed in a particular order as shown, or as a series of sequences, or as all described operations being performed to achieve a desired result. Multitasking and parallel processing can be advantageous in certain environments. In addition, it should be understood that the division of various system components in the above-described embodiments does not require such division in all embodiments. The above-described app components and systems may generally be implemented as a package in a single software product or multiple software products.

The present invention described above is capable of various substitutions, modifications and changes without departing from the technical spirit of the present invention to those of ordinary skill in the technical field to which the present invention pertains. It is not limited by the drawings.

100: Tracking Authorization Server
200: Property Management Server
300: Medical cloud server
310: storage server
330: Outsourced server
410: data user terminal
430: Data owner terminal

Claims (8)

A tracking authority server that receives user registration from users who will use the medical cloud and grants anonymous ID values to users who use the cloud;
an attribute management server that manages the attributes of users using the medical cloud and generates secret keys corresponding to the attributes; and
A patient's medical data sharing system in a medical cloud environment that includes a medical cloud server that stores and manages data, performs user access control, and partial decryption of ciphertext. According to claim 1,
The property management server is,
Register user attribute information based on the anonymous ID value granted from the tracking authority server from the user, generate public parameters and master keys, generate a user secret key with the registered user attribute information, and send data to the user terminal. A patient medical data sharing system in a medical cloud environment that provides public parameters and user secret keys and transmits public parameters to the data owner terminal of the data owner who registered the data. According to claim 1,
The medical cloud server is,
Receive and store the ciphertext from the data owner terminal, register the ciphertext, receive a token from the data user terminal, partially decrypt the ciphertext, send the partially decrypted ciphertext to the data user terminal, and verify the message obtained after performing the final decryption. A patient's medical data sharing system in a medical cloud environment characterized by ensuring the integrity of the data. According to claim 3,
The medical cloud server is,
A storage server that stores and manages ciphertext; and
A system for sharing patient medical data in a medical cloud environment, comprising an outsourced server that manages user access and performs partial decryption. In a data sharing method in a patient's medical data sharing system in a medical cloud environment,
A tracking authority server receiving user registration from a user who will use the medical cloud and granting an anonymous ID value to the user who will use the cloud;
A property management server managing the properties of a user using the medical cloud and generating a secret key corresponding to the properties; and
A data sharing method comprising: a medical cloud server storing and managing data, performing user access control and partial decryption of ciphertext. According to claim 5,
The step of the attribute management server managing the attributes of a user using the medical cloud and generating a secret key corresponding to the attribute,
registering user attribute information based on an anonymous ID value granted from the tracking authority server from the user;
generating public parameters and a master key, and generating a user secret key using the registered user attribute information; and
A data sharing method comprising: providing public parameters and a user secret key to a data user terminal, and transmitting the public parameters to the data owner terminal of the data owner who registered the data. According to claim 5,
The step of the medical cloud server storing and managing data, performing user access control and partial decryption of ciphertext,
Receiving the ciphertext from the data owner terminal, storing the ciphertext, and registering the ciphertext;
Receiving a token from a data user terminal and partially decrypting the ciphertext; and
A data sharing method comprising: transmitting the partially decrypted ciphertext to a data user terminal and verifying the message obtained after performing final decryption. A computer-readable recording medium on which a computer program is recorded, for performing the data sharing method according to any one of claims 5 to 7.