DICOM medical image data encryption and desensitization method based on chaos theory

Abstract

The invention discloses a DICOM (Digital Imaging and Communications in Medicine) medical image data encryption and desensitization method based on a chaos theory. The method comprises the following steps: (1) a system reads medical image data in a DICOM format; (2) extracting an encryption item and a desensitization item: extracting an item needing to be encrypted (namely encryption item data) and an item needing to be desensitized (namely desensitization item data) from the DICOM data; (3) judging whether the data is a desensitization item or an encryption item: judging the extracted data to determine whether the data is the desensitization item or the encryption item; (4) desensitization item data processing: if the data are desensitization item data, setting the data to be null; (5) encryption item data processing: if the data are encryption item data, forming an encryption item P, and entering an encryption process; and (6) decrypting the data of the encryption item P. According to the method, the sensitive information in the medical image data can be desensitized, meanwhile, the non-sensitive information is encrypted to ensure the privacy and security of the data, and the method has good practical application value.

Description

Technical Field

[0001] The invention belongs to the technical field of medical image data protection, and relates to DICOM medical image data encryption and desensitization designed by using chaos theory, and specifically is a DICOM medical image data encryption and desensitization method based on chaos theory. Background Art

[0002] DICOM (Digital Imaging and Communications in Medicine) format is widely used in the storage, transmission and sharing of medical images. DICOM files contain not only the medical images themselves, but also the patient's personal sensitive information (such as name, ID number, phone number, address, etc.). In most cases, this sensitive information needs to be desensitized during storage or transmission to protect the patient's privacy.

[0003] However, traditional desensitization methods can only delete or empty sensitive data, and lack encryption protection for non-sensitive information. Therefore, how to ensure data privacy and prevent sensitive information leakage without affecting the validity of image data has become an urgent problem to be solved.

[0004] The pseudo-random sequence generation and encryption method based on chaos theory can provide an efficient and secure encryption and desensitization solution, which uses the pseudo-random sequence generated by the key to encrypt the non-sensitive data in DICOM data and desensitize the sensitive information at the same time. Summary of the invention

[0005] In the face of privacy and security challenges faced by DICOM medical image data in the process of storage, transmission and sharing, the purpose of this invention is to propose a DICOM medical image data encryption and desensitization method based on chaos theory. This method generates a pseudo-random sequence by combining two chaotic maps, Logistic mapping and Chebyshev mapping, to achieve encryption processing of non-sensitive information and effective desensitization processing of sensitive information.

[0006] The present invention is achieved by adopting the following technical solutions:

[0007] A DICOM medical image data encryption and desensitization method based on chaos theory includes the following steps:

[0008] (1) The system reads medical imaging data in DICOM format.

[0009] (2) Extracting encrypted items and desensitized items: Extracting items that need to be encrypted (i.e., encrypted item data) and items that need to be desensitized (i.e., desensitized item data) from DICOM data.

[0010] (3) Determine whether the data is desensitized or encrypted: Determine whether the extracted data is desensitized or encrypted.

[0011] (4) Desensitized data processing: If the data is desensitized, set the data to empty.

[0012] (5) Encryption item data processing: If it is encryption item data, it constitutes encryption item P and enters the encryption process; the encryption process is as follows:

[0013] 5.1. Generate key: Generate a pseudo-random sequence S according to the key K = (K1, K2) set by the user;

[0014] 5.2. Encryption of encrypted items: For each data value P in the encrypted item P i Encryption is performed using the corresponding value S in the pseudo-random sequence S i Perform an XOR operation, Get each encrypted data value C of the encrypted data item C i ;

[0015] 5.3. Save the encrypted DICOM image: Save the encrypted data value C i Write DICOM data and save it.

[0016] (6) The encrypted item P data is decrypted. The decryption process is as follows:

[0017] 6.1. Generate key: Generate a pseudo-random sequence S according to the key K = (K1, K2) set by the user;

[0018] 6.2. Decrypting encrypted items: For each data value P in the encrypted item P i Decryption is performed using the corresponding value S in the pseudo-random sequence S i Perform an XOR operation, Get each data value P in the decrypted encrypted item P i ;

[0019] 6.3. Save the decrypted DICOM image: i Write DICOM data and save it.

[0020] Further preferably, the pseudo-random sequence S is generated as follows:

[0021] 1) Set the initial key K = (K1, K2), where K1 is the initial value X0 of the Logistic map, and K2 is the initial value X′0 of the Chebyshev map;

[0022] 2) The Logistic mapping formula is as follows:

[0023] X n+1 = r·X n ·(1-Xn )

[0024] Among them, r is the chaos parameter, and its value range is 3.5699456 <r≤4,X n is the state value of the nth iteration, ranging from 0 ≤ x n ≤1;

[0025] The Logistic map is iterated multiple times to generate a chaotic sequence M1 = {X1, X2, ..., X n};

[0026] 3) The Chebyshev mapping formula is as follows:

[0027] X n+1 ′=cos(k·arccos(X n ′))

[0028] Where k is the order of the mapping, which is an integer greater than 1, and X n ′ is the state value of the nth iteration, ranging from -1≤X n ′≤1;

[0029] The Chebyshev map is iterated multiple times to generate the chaotic sequence M2 = {X′1, X′2, ..., X′ n};

[0030] 4) Perform XOR operation on M1 and M2 to generate the final pseudo-random sequence S = {S1, S2, ..., S n},in

[0031] The method of the present invention is designed to ensure that patient privacy is protected to the greatest extent possible and to prevent the leakage of sensitive information without compromising the validity of the image data, thereby meeting the privacy and security requirements of medical image data during storage, transmission and sharing.

[0032] Compared with the prior art, the present invention has the following advantages: the present invention selects Logistic mapping and Chebyshev mapping as the basis for generating pseudo-random sequences because they each have unique advantages, which combined can provide stronger security for the encryption algorithm.

[0033] First, the advantage of the Logistic map is its chaotic properties. Under certain parameter values, the Logistic map exhibits chaotic behavior, which means that it is very sensitive to initial conditions and can produce unpredictable sequences. The chaotic properties and behavior of the Logistic map are well understood, which helps to ensure the reliability of the algorithm.

[0034] Second, the advantage of Chebyshev mapping is that it has good mathematical properties, such as periodicity and symmetry, which makes it easier to analyze and control in some cases; chaotic behavior Under appropriate parameters, Chebyshev mapping can also exhibit chaotic behavior and provide unpredictable sequences; sensitivity The sensitivity of Chebyshev mapping to initial conditions is similar to that of Logistic mapping, which helps to increase the randomness and unpredictability of the encryption process.

[0035] Third, the combination of Logistic mapping and Chebyshev mapping: 1) Enhanced unpredictability: Combining the two mappings can increase the unpredictability of the sequence because they each have different chaotic characteristics and behavior patterns. 2) Larger key space: By combining the two mappings, more complex pseudo-random sequences can be generated, thereby providing a larger key space and increasing the difficulty of cracking. 3) Improved security: The combination of the two mappings can improve the security of the encryption algorithm because even if certain characteristics of one mapping are cracked, the characteristics of the other mapping can still provide protection. Therefore, the combined use of Logistic mapping and Chebyshev mapping can provide encryption algorithms based on chaos theory with higher security, larger key space, and stronger unpredictability, which are all necessary for encryption algorithms to protect sensitive data.

[0036] The present invention is reasonably designed and can desensitize sensitive information in medical imaging data while encrypting non-sensitive information to ensure the privacy and security of the data, and has great practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 The flowchart of the DICOM medical image data encryption and desensitization method based on chaos theory of the present invention is shown. DETAILED DESCRIPTION

[0040] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0041] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0042] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0043] As a standard format in the field of medical imaging, the DICOM format contains not only the image data itself, but also a large amount of personal sensitive information of patients, such as name, ID number, telephone number and address. Traditional desensitization methods usually only involve the deletion or blanking of sensitive data, while ignoring the encryption protection of non-sensitive information, which limits the security and integrity of the data to a certain extent. The embodiment of the present invention specifically provides a DICOM medical imaging data encryption desensitization method based on chaos theory, comprising the following steps:

[0044] (1) Read DICOM medical image data: Use VTK to read medical image data in DICOM format and convert it into data types that can be processed by OpenCV.

[0045] (2) Extracting encrypted items and desensitized items: Extracting items that need to be encrypted (encrypted item data) and items that need to be desensitized (desensitized item data) from DICOM data; for example, identifying encrypted items (such as encrypted item data: height, weight, age, etc.) and desensitized items (such as desensitized item data: name, ID number, address, telephone number, etc.) in DICOM data.

[0046] (3) Determine whether the data is desensitized or encrypted: Determine whether the extracted data is desensitized or encrypted.

[0047] (4) Desensitized data processing: If the data is desensitized, set the data to empty.

[0048] (5) Encryption item data processing: If it is encryption item data, it constitutes encryption item P and enters the encryption process; the encryption process is as follows:

[0049] 5.1. Generate key: Generate a pseudo-random sequence S according to the key K = (K1, K2) set by the user, S = {S1, S2, ..., S n};

[0050] 5.2. Encryption of encrypted items: For each data value P in the encrypted item Pi Encryption is performed using the corresponding value S in the pseudo-random sequence S i Perform an XOR operation, Get each encrypted data value C in the encrypted data item C i ;

[0051] Where P = {P1, P2, ..., P n}, C={C1,C2,...,C n}, the same below;

[0052] 5.3. Save the encrypted DICOM image: Save the encrypted data value C i Write DICOM data and save it.

[0053] (6) Decrypt the encrypted item P data. The decryption process is as follows:

[0054] 6.1. Read encrypted DICOM medical images: Use VTK to read encrypted DICOM data and convert it into data types that can be processed by OpenCV;

[0055] 6.2. Generate key: Generate a pseudo-random sequence S according to the key K = (K1, K2) set by the user;

[0056] 6.2. Decrypting encrypted items: For each data value P in the encrypted item P i Decryption is performed using the corresponding value S in the pseudo-random sequence S i Perform an XOR operation, Get each data value P in the decrypted encrypted item P i ;

[0057] 6.4. Save the decrypted DICOM image: i Write DICOM data and save it.

[0058] Based on chaos theory, the present invention uses two chaotic maps, Logistic mapping and Chebyshev mapping, to generate pseudo-random sequences. Logistic mapping is a typical nonlinear chaotic function with complex chaotic behavior; Chebyshev mapping is very sensitive to its initial conditions and can generate long-term unpredictable chaotic sequences. In the above steps (5) and (6), the two chaotic maps are combined to generate the pseudo-random sequence S as follows:

[0059] 1) Set the initial key K = (K1, K2), where K1 is the initial value X0 of the Logistic map, and K2 is the initial value X′0 of the Chebyshev map.

[0060] 2) The Logistic mapping formula is as follows:

[0061] X n+1 = r·X n ·(1-X n )

[0062] Among them, r is the chaos parameter, and its value range is 3.5699456 <r≤4,X n is the state value of the nth iteration, ranging from 0 ≤ x n ≤1.

[0063] The Logistic map is iterated multiple times to generate a chaotic sequence M1 = {X1, X2, ..., X n}.

[0064] 3) The Chebyshev mapping formula is as follows:

[0065] X n+1 ′=cos(k·arccos(X n ′))

[0066] Where k is the order of the mapping, which is an integer greater than 1, and X n ′ is the state value of the nth iteration, ranging from -1≤X n ′≤1.

[0067] The Chebyshev map is iterated multiple times to generate the chaotic sequence M2 = {X′1, X′2, ..., X′ n}.

[0068] 4) Perform XOR operation on M1 and M2 to generate the final pseudo-random sequence S = {S1, S2, ..., S n},in

[0069] Specific implementation examples Figure 1 As shown below

[0070] 1. Start: The process starts.

[0071] 2. Read DICOM medical image data: First, the system reads the medical image data in DICOM format.

[0072] 3. Extract encrypted items and desensitized items: Extract items that need to be encrypted (encrypted item data) and items that need to be desensitized (desensitized item data) from DICOM data.

[0073] 4. Determine whether the data is desensitized or encrypted: Determine whether the extracted data is desensitized or encrypted.

[0074] 5. Anonymous data processing: If it is anonymized data, set this data to empty.

[0075] 6. Encrypted item data processing: If it is encrypted item data, enter the encryption process.

[0076] 7. Set the key: The user sets the key K, which consists of two parts (k1, k2).

[0077] 8. Generate pseudo-random sequence: Generate pseudo-random sequence M1 according to Logistic mapping; generate pseudo-random sequence M2 according to Chebyshev mapping.

[0078] 9. Perform XOR operation: Perform XOR operation on the two pseudo-random sequences M1 and M2 to generate the final pseudo-random sequence S.

[0079] 10. Encrypt the encryption item P: Use the corresponding value in the pseudo-random sequence S to perform an XOR operation with each data value in the encryption item P to obtain the encrypted encrypted data item C.

[0080] 11. Write encrypted data item C to DICOM data: Write the encrypted data value back to the DICOM data.

[0081] 12. Read the encrypted DICOM data: During the decryption process, first read the encrypted DICOM data.

[0082] 13. Get the key: During the decryption process, get the key used for the previous encryption.

[0083] 14. Decryption process: Use the corresponding value in the pseudo-random sequence S to perform an XOR operation with the encrypted data item C to obtain the decrypted encrypted item P data value.

[0084] 15. Write the decrypted encrypted item P data value into the DICOM data: Write the decrypted data value back into the DICOM data.

[0085] 16. End: The process ends.

[0086] The above flowchart shows the entire process from reading DICOM data to encryption, desensitization, and then decryption, ensuring the privacy and security of medical imaging data during storage, transmission, and sharing.

[0087] The above is only a specific implementation of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions are given with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A DICOM medical image data encryption and desensitization method based on chaos theory, characterized by: The steps include: (1) The system reads medical imaging data in DICOM format; (2) Extracting encrypted items and desensitized items: extracting items that need to be encrypted, i.e., encrypted item data, and items that need to be desensitized, i.e., desensitized item data, from DICOM data; (3) Determine whether the data is desensitized or encrypted: Determine whether the extracted data is desensitized or encrypted; (4) Anonymous data processing: If the data is anonymized, set the data to empty; (5) Encrypted item data processing: If it is encrypted item data, it constitutes the encrypted item P and enters the encryption process; (6) Decryption process of the encrypted item P data.

2. The method for encrypting and desensitizing DICOM medical image data based on chaos theory according to claim 1, characterized in that: The encryption process in step (5) is as follows: 5.

1. Generate key: Generate a pseudo-random sequence S according to the key K = (K1, K2) set by the user; 5.

2. Encryption of encrypted items: For each data value P in the encrypted item P i Encryption is performed using the corresponding value S in the pseudo-random sequence S i Perform an XOR operation, Get each encrypted data value C of the encrypted data item C i ; 5.

3. Save the encrypted DICOM image: Save the encrypted data value C i Write DICOM data and save it.

3. The method for encrypting and desensitizing DICOM medical image data based on chaos theory according to claim 2, characterized in that: The decryption process in step (6) is as follows: 6.

1. Generate key: Generate a pseudo-random sequence S according to the key K = (K1, K2) set by the user; 6.

2. Decrypting encrypted items: For each data value P in the encrypted item P i Decryption is performed using the corresponding value S in the pseudo-random sequence S i Perform an XOR operation, Get each data value P in the decrypted encrypted item P i ; 6.

3. Save the decrypted DICOM image: i Write DICOM data and save it.

4. A DICOM medical image data encryption and desensitization method based on chaos theory according to claim 2 or 3, characterized in that: The steps for generating the pseudo-random sequence S are as follows: 1) Set the initial key K = (K1, K2), where K1 is the initial value X0 of the Logistic map, and K2 is the initial value X′0 of the Chebyshev map; 2) Perform multiple iterations on the Logistic map to generate a chaotic sequence M1 = {X1, X2, ..., X n }; 3) Perform multiple iterations of the Chebyshev map to generate a chaotic sequence M2 = {X′1, X′2, ..., X′ n }; 4) Perform an XOR operation on M1 and M2 to generate the final pseudo-random sequence S = {S1, S2, ..., S n },in 5. The method for encrypting and desensitizing DICOM medical image data based on chaos theory according to claim 4, characterized in that: The Logistic mapping formula is as follows: X n+1 =r·X n ·(1-X n ) Among them, r is the chaos parameter, and its value range is 3.5699456 <r≤4,X n is the state value of the nth iteration, ranging from 0 ≤ x n ≤1; The Chebyshev mapping formula is as follows: X n+1 ′=coS(k·arccos(X n ′)) Where k is the order of the mapping, which is an integer greater than 1, and X n ′ is the state value of the nth iteration, ranging from -1≤X n ′≤1.

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