Editable medical block chain system with privacy protection function

Abstract

The invention belongs to the technical field of information security, provides an editable medical block chain system with a privacy protection function, and constructs an editable medical block chain system PRHBS with a privacy protection function based on a trap door chameleon hash function, an attribute-based encryption algorithm, puncturable encryption and a key distribution mechanism. Fine-grained editability based on block-level medical data is realized, and dual application requirements of a medical block chain system on key distribution flexibility and data confidentiality are met; according to the method, formalized definition and general construction of the PRHBS are given, and safety proof and experimental analysis show that the PRHBS greatly improves the overall performance and functions of the medical block chain system and has good practicability in practical application.

Description

Technical Field

[0001] The present invention belongs to the field of information security technology, and specifically relates to an editable medical blockchain system with a privacy protection function. Background Art

[0002] As an open and tamper-proof distributed ledger, blockchain has been integrated and applied to multiple fields such as digital finance, Internet of Things, intelligent manufacturing, and supply chain management. With the development of the medical and health industry, the medical blockchain system can help people realize the safe sharing of electronic medical records, prevent patients' medical data from being tampered with, strengthen the management of drug supply chain, and help medical and health researchers unlock genetic codes. It has become one of the most promising blockchain applications.

[0003] While using the medical blockchain system to share electronic medical data, it is also necessary to protect the privacy of patients' sensitive information. However, the inherent immutability of the blockchain system makes the data unmodifiable once it is on the chain, which conflicts with the privacy protection of medical data. Editable blockchain technology can effectively update the data on the chain, providing a better way to solve the data solidification problem faced by blockchain. However, the existing editable blockchain solutions have high encryption overhead and insecure data storage, which cannot meet the actual needs of medical and health applications.

[0004] Therefore, there is an urgent need to study an editable medical blockchain system with privacy protection function, so as to simultaneously achieve efficient editability of block-level medical data and privacy protection of data. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides an editable medical blockchain system with a privacy protection function to solve the problems that the existing related solutions proposed in the background technology have large encryption overhead, insecure data storage, and cannot meet the actual needs of medical and health applications.

[0006] An editable medical blockchain system with privacy protection function includes five types of entities, namely medical center HC, data owners DOs, data users DUs, data modifiers DMs and miners. The workflow includes four stages, namely: system initialization, data upload, data modification and data retrieval;

[0007] During the system initialization phase, HC initializes the system, secretly stores the master private key, and issues the master public key to all other entities. At the same time, HC sends the generated public key and initial private key to DU, and then DU sends the generated subsequent private key sk i Sent to other DUs, where the decryption authority of the subsequent private key is less than the original private key sk i-1 ,HC also sends the generated private key to DM;

[0008] In the data upload phase, it is divided into two parts: data encryption and block generation. In the data encryption part, each DO runs the encryption algorithm to generate ciphertext, and the ciphertext is sent to the miners. In the block generation part, after receiving a batch of ciphertext, the miners will run the block generation algorithm to obtain the genesis block. At this time, if the blockchain exists, the genesis block will be sent to other blocks that have not been initialized. Otherwise, the block increment algorithm will be run to obtain the subsequent block, and the subsequent block will be sent to other blocks for block increment.

[0009] In the data modification phase, editing and deletion are performed by generating modification blocks;

[0010] In the data retrieval phase, it is divided into two parts: data acquisition and data decryption. When acquiring data, DU takes out the ciphertext from the blockchain and finds the blockchain message, which contains the information of the ciphertext. Then DU runs the verification algorithm to get the bit b. If b=1, DU runs the decryption algorithm to decrypt the original message from the ciphertext.

[0011] The specific steps include:

[0012] S1. The medical center runs the probabilistic system initialization algorithm Setup, inputs the system security parameters, and outputs the system's master public key mpk and master private key msk;

[0013] S2. The medical center runs the probabilistic initial key generation algorithm KeyGen i , input the master private key msk and the maximum number of tags for each ciphertext d, and output the public key pk and the initial private key sk0;

[0014] S3. The data user runs the probabilistic successor key generation algorithm KeyGen s , enter the public key pk, private key sk i-1 and label t, output the subsequent private key sk i , where sk i Able to decrypt any ciphertext except the one encrypted with tag t;

[0015] S4. The medical center runs the probabilistic modifier key generation algorithm KeyGen m , input the master private key msk and attribute set S, output the private key sk;

[0016] S5. The data owner runs the probabilistic encryption algorithm Enc, inputting the public key pk, identity id, message m and label list {t i} i∈[d] , output ciphertext c;

[0017] S6. The miner runs the probabilistic block generation algorithm BlkGen, inputs the master public key mpk, and accesses the structure and Cipher Texts Output block message m blk,0 ;

[0018] S7. The miner runs the probabilistic block increment algorithm BlkApp, inputs the master public key mpk, and accesses the structure The hash value h of the previous block i-1 and Cipher Texts Output block message m blk,i ;

[0019] S8. The data modifier runs the deterministic block modification algorithm BlkMod, inputs the master public key mpk, private key sk, and ciphertext set and block message m blk,i , output block message m' blk,i ;

[0020] S9. The data modifier runs the deterministic block deletion algorithm BlkRem, inputting the master public key mpk, the private key sk and two block messages m blk,i ,m blk,i+1 , output message in Indicates the i-th block deleted;

[0021] S10. The data user runs the deterministic verification algorithm Ver, inputting the ciphertext c and its related block message m blk,i , output bit b∈{0,1}, where b=1 if the ciphertext c is a valid message in the blockchain, otherwise b=0;

[0022] S11. The data user runs the deterministic decryption algorithm Dec and inputs the public key pk and private key sk i , ciphertext c and label list {t i} i∈[d] , output plaintext m.

[0023] Preferably, the step S1 specifically includes:

[0024] The medical center first selects a bilinear map in are all multiplicative cyclic groups of prime order p, g is the generator, and the generating parameters are Then select a random number Output master private key msk = a, master public key mpk = (1 λ ,g,u,h,w,v,e(g,g) a ).

[0025] Preferably, in step S2, the medical center runs a probabilistic initial key generation algorithm KeyGen i, generate the public key pk and the initial private key sk0, including:

[0026] HC Selection Standard Collusion-Resistant Hash Function and random numbers Then set g1 = g α ,g2=g β and a d-degree polynomial q(·) subject to the constraint q(0) = β, defining a function V(x) = g q(x) , let t0 be a marker that is not used when the algorithm is running normally, and calculate K 0,2 =V(H(t0)) r ,K 0,3 =g r ,K 0,4 =y0, returns the public key pk=(g1,g2,g q(1) ,...,g q(d) ) and private key sk0=(K 0,1 ,K 0,2 ,K 0,3 ,K 0,4 ).

[0027] Preferably, in step S3, the data user runs the probabilistic successor key generation algorithm KeyGen s , output the subsequent private key sk i , specifically including:

[0028] DU random selection calculate Returns the private key sk i =(sk' i ,sk1,...,sk i-1 ,sk i ).

[0029] Preferably, the step S4 is a probabilistic modifier key generation algorithm, outputting a private key sk, specifically comprising:

[0030] The medical center runs the algorithm to parse the attribute set Random Selection And calculate K0 = g a w r and K1 = g r , for all τ∈[k], calculate and Return private key sk=(S,K0,K1,{K τ,2 ,K τ,3} τ∈[k] );

[0031] In step S5, the data owner encrypts the message m to generate the ciphertext c, which specifically includes:

[0032] Data owner random selection Calculate C1 = m·e(g1,g2) s , C2=g s , C 3,1 =V(H(t1)) s ,...,C 3,d =V(H(t d )) s , return the ciphertext c = (id, (t1, ..., t d ),C1,C2,C 3,1 ,...,C 3,d ).

[0033] Preferably, in step S6, the miner runs a probabilistic block generation algorithm and outputs an initial block message m blk,0 , specifically including:

[0034] Miners first parse a set of ciphertext Get (c1,c2,...,c k ), then the quadratic residual The subgroup of chooses a generator And select a random value x∈{1,2,...,q-1}, set Then it randomly selects a hash value h' in the hash domain and randomly selects where ctr0∈{0,1} 32 In the temporary domain, calculate Parsing access structure The message domain The encryption algorithm is then randomly selected calculate Random Selection Calculate C = x·e(g,g) at and C0 = g t , for all τ∈[l], calculate and Return block information

[0035] Preferably, in step S7, the miner runs a probabilistic block increment algorithm and outputs an incremented block message m blk,i , specifically including:

[0036] Miners first parse a set of ciphertext Get (c1,c2,...,c k), then the quadratic residual The subgroup of chooses a generator And select a random value x∈{1,2,...,q-1}, set Random Selection where ctr i ∈{0,1} 32 In the temporary domain, calculate Parsing access structure The message domain The encryption algorithm is then randomly selected calculate Random Selection Calculate C = x·e(g,g) at and C0 = g t , for all τ∈[l], calculate and Return block information

[0037] Preferably, in step S8, the data modifier runs a probabilistic block modification algorithm and outputs a modified block message m' blk,i , specifically including:

[0038] Miners parse a set of ciphertext Calculate message domain The I-th line of the message is calculate Constants in Derived Restore x = C / B, and randomly select k∈{1,2,...,q-1}, and calculate Finally, the modified block message is returned

[0039] Preferably, in step S9, the data modifier runs a deterministic block deletion algorithm and outputs a message in Indicates the i-th block to be deleted, including:

[0040] Miners parse a set of ciphertext Calculate message domain The I-th line of the message is calculate Constants in Derived Restore x=C / B of the i+1th block, and randomly select k∈{1,2,...,q-1} to calculate set up Return message

[0041] Preferably, in step S10, the data user runs a deterministic verification algorithm and outputs a bit b∈{0,1}, wherein if the ciphertext c is valid information in the blockchain, then b=1, otherwise, b=0, specifically including:

[0042] DU receives ciphertext c and block message m blk,i After that, calculate If h=h', output 1, otherwise, output 0;

[0043] In step S11, the data user runs a deterministic decryption algorithm to decrypt the ciphertext c into plaintext m, which specifically includes:

[0044] DU receives the public key pk and private key sk i , ciphertext c and label list {t i} i∈[d] After that, calculate a set of coefficients w1,...,w d ,w * Make For all j∈{0,1,...,i}, calculate Return message

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The present invention constructs an editable medical blockchain system PRHBS with privacy protection function based on trapdoor chameleon hash function, attribute-based encryption algorithm, pierceable encryption algorithm and key distribution mechanism, constructs a flexible key distribution mechanism, realizes fine-grained editability based on block-level medical data, and meets the dual application requirements of medical blockchain system for key distribution flexibility and data confidentiality. The present invention provides a formal definition and general construction of PRHBS, and security proof and experimental analysis show that PRHBS greatly improves the overall performance and function of the medical blockchain system, and has good practicality in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a system model diagram of the editable medical blockchain system with privacy protection function of the present invention;

[0048] Figure 2 This is a flow chart of the editable medical blockchain system with privacy protection function of the present invention. DETAILED DESCRIPTION

[0049] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0050] As attached Figure 1 As shown:

[0051] Embodiment 1: The present invention provides an editable medical blockchain system with privacy protection function, including five types of entities, namely, medical center HC, data owners DOs, data users DUs, data modifiers DMs and miners, and the workflow includes four stages, namely: system initialization, data upload, data modification and data retrieval;

[0052] During the system initialization phase, HC initializes the system, secretly stores the master private key, and issues the master public key to all other entities. At the same time, HC sends the generated public key and initial private key to DU, and then DU sends the generated subsequent private key sk i Sent to other DUs, where the decryption authority of the subsequent private key is less than the original private key sk i-1 ,HC also sends the generated private key to DM;

[0053] In the data upload phase, it is divided into two parts: data encryption and block generation. In the data encryption part, each DO runs the encryption algorithm to generate ciphertext, and the ciphertext is sent to the miners. In the block generation part, after receiving a batch of ciphertext, the miners will run the block generation algorithm to obtain the genesis block. At this time, if the blockchain exists, the genesis block will be sent to other blocks that have not been initialized. Otherwise, the block increment algorithm will be run to obtain the subsequent block, and the subsequent block will be sent to other blocks for block increment.

[0054] In the data modification phase, editing and deletion are performed by generating modification blocks;

[0055] In the data retrieval stage, it is divided into two parts: data acquisition and data decryption. During data acquisition, DU takes out the ciphertext from the blockchain and finds the blockchain message, which contains the ciphertext information. Then DU runs the verification algorithm to obtain bit b. If b=1, DU runs the decryption algorithm to decrypt the original message from the ciphertext.

[0056] As attached Figure 2 As shown:

[0057] Embodiment 2: An editable medical blockchain system with privacy protection function provided by the present invention specifically includes the following steps:

[0058] S1. The medical center runs the probabilistic system initialization algorithm Setup, inputs the system security parameters, and outputs the system's master public key mpk and master private key msk. The medical center first selects a bilinear mapping in are all multiplicative cyclic groups of prime order p, g is the generator, and the generating parameters are Then select a random number Output master private key msk = a, master public key mpk = (1 λ ,g,u,h,w,v,e(g,g) a ).

[0059] S2. The medical center runs the probabilistic initial key generation algorithm KeyGen i , input the master private key msk and the maximum number of tags for each ciphertext d, output the public key pk and the initial private key sk0; HC selects the standard anti-collusion hash function and random numbers Then set g1 = g α ,g2=g β and a d-degree polynomial q(·) subject to the constraint q(0) = β, defining a function V(x) = g q(x) , let t0 be a marker that is not used when the algorithm is running normally, and calculate K 0,2 =V(H(t0)) r ,K 0,3 =g r ,K 0,4 = t0, return the public key pk = (g1, g2, g q(1) ,...,g q(d) ) and private key sk0=(K 0,1 ,K 0,2 ,K 0,3 ,K 0,4 ).

[0060] S3. The data user runs the probabilistic successor key generation algorithm KeyGen s , enter the public key pk, private key sk i-1 and label t, output the subsequent private key sk i , where sk i Able to decrypt any ciphertext except the one encrypted with tag t; DU randomly selects calculate Returns the private key sk i =(sk' i ,sk1,...,sk i-1 ,sk i ).

[0061] S4. The medical center runs the probabilistic modifier key generation algorithm KeyGen m, input the master private key msk and attribute set S, output the private key sk; the medical center runs the algorithm to parse the attribute set Random Selection And calculate V0 = g a w r and K1 = g r , for all τ∈[k], calculate and Return private key sk=(S,K0,K1,{K τ,2 ,K τ,3} τ∈[k] ).

[0062] S5. The data owner runs the probabilistic encryption algorithm Enc, inputting the public key pk, identity id, message m and label list {t i} i∈[d] , output ciphertext c; the data owner randomly selects Calculate C1 = m·e(g1,g2) s , C2=g s , C 3,1 =V(H(t1)) s ,...,C 3,d =V(H(t d )) s , return the ciphertext c = (id, (t1, ..., t d ),C1,C2,C 3,1 ,...,C 3,d ).

[0063] S6. The miner runs the probabilistic block generation algorithm BlkGen, inputs the master public key mpk, and accesses the structure and Cipher Texts Output block message m blk,0 ; Miners first parse a set of ciphertext Get (c1,c2,...,c k ), then the quadratic residual The subgroup of chooses a generator And select a random value x∈{1,2,...,q-1}, set y= Then it randomly selects a hash value h' in the hash domain and randomly selects where ctr0∈{0,1} 32 In the temporary domain, calculate Parsing access structure The message domain The encryption algorithm is then randomly selected calculate Random Selection Calculate C = x·e(g,g) at and C0 = g t , for all τ∈[l], calculate and Return block information

[0064] S7. The miner runs the probabilistic block increment algorithm BlkApp, inputs the master public key mpk, and accesses the structure The hash value h of the previous block i-1 and Cipher Texts Output block message m blk,i ; Miners first parse a set of ciphertext Get (c1,c2,...,c k ), then the quadratic residual The subgroup of chooses a generator And select a random value x∈{1,2,...,q-1}, set Random Selection where ctr i ∈{0,1} 32 In the temporary domain, calculate Parsing access structure The message domain The encryption algorithm is then randomly selected calculate Random Selection Calculate C = x·e(g,g) at and C0 = g t , for all τ∈[l], calculate and Return block information

[0065] S8. The data modifier runs the deterministic block modification algorithm BlkMod, inputs the master public key mpk, private key sk, and ciphertext set and block message m blk,i , output block message m' blk,i ; Miners parse a set of ciphertext Calculate message domain The I-th line of the message is calculate Constants in Derived Restore x = C / B, and randomly select k∈{1,2,...,q-1}, and calculate Finally, the modified block message is returned

[0066] S9. The data modifier runs the deterministic block deletion algorithm BlkRem, inputting the master public key mpk, the private key sk and two block messages m blk,i ,m blk,i+1 , output message in Indicates the i-th block deleted; miners parse a set of ciphertext Calculate message domain The I-th line of the message is calculate Constants in Derived Restore x=C / B of the i+1th block, and randomly select k∈{1,2,...,q-1} to calculate set up Return message

[0067] S10. The data user runs the deterministic verification algorithm Ver, inputting the ciphertext c and its related block message m blk,i , output bit b∈{0,1}, where b=1 if the ciphertext c is a valid message in the blockchain, otherwise b=0; DU receives the ciphertext c and the block message m blk,i After that, calculate If h=h', output 1, otherwise, output 0.

[0068] S11. The data user runs the deterministic decryption algorithm Dec and inputs the public key pk and private key sk i , ciphertext c and label list {t i} i∈[d] , output plaintext m. DU receives public key pk and private key sk i , ciphertext c and label list {t i} i∈[d] After that, calculate a set of coefficients w1,...,w d ,w * Make For all j∈{0,1,...,i}, calculate Return message

[0069] As can be seen from the above, the present invention proposes an editable medical blockchain system (PRHBS) with privacy protection function. Based on the trapdoor chameleon hash function, attribute-based encryption algorithm, and pierceable encryption algorithm, a flexible key distribution mechanism is constructed, which realizes fine-grained editability based on block-level medical data, meets the dual application requirements of the medical blockchain system for key distribution flexibility and data confidentiality, and gives a formal definition and general construction of PRHBS. Security proof and experimental analysis show that PRHBS greatly improves the overall performance and function of the medical blockchain system and has good practicality in practical applications.

[0070] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0071] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0072] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An editable medical blockchain system with privacy protection function, characterized by: It includes five types of entities, namely, medical centers HC, data owners DOs, data users DUs, data modifiers DMs, and miners. The workflow includes four stages, namely: system initialization, data upload, data modification, and data retrieval; During the system initialization phase, HC initializes the system, secretly stores the master private key, and issues the master public key to all other entities. At the same time, HC sends the generated public key and initial private key to DU, and then DU sends the generated subsequent private key sk i Sent to other DUs, where the decryption authority of the subsequent private key is less than the original private key sk i-1 ,HC also sends the generated private key to DM; In the data upload phase, it is divided into two parts: data encryption and block generation. In the data encryption part, each DO runs the encryption algorithm to generate ciphertext, and the ciphertext is sent to the miners. In the block generation part, after receiving a batch of ciphertext, the miners will run the block generation algorithm to obtain the genesis block. At this time, if the blockchain exists, the genesis block will be sent to other blocks that have not been initialized. Otherwise, the block increment algorithm will be run to obtain the subsequent block, and the subsequent block will be sent to other blocks for block increment. In the data modification phase, editing and deletion are performed by generating modification blocks; In the data retrieval phase, it is divided into two parts: data acquisition and data decryption. When acquiring data, DU takes out the ciphertext from the blockchain and finds the blockchain message, which contains the information of the ciphertext. Then DU runs the verification algorithm to get the bit b. If b=1, DU runs the decryption algorithm to decrypt the original message from the ciphertext. The specific steps include: S1. The medical center runs the probabilistic system initialization algorithm Setup, inputs the system security parameters, and outputs the system's master public key mpk and master private key msk; S2. The medical center runs the probabilistic initial key generation algorithm KeyGen i , input the master private key msk and the maximum number of tags for each ciphertext d, and output the public key pk and the initial private key sk0; S3. Data users run the probabilistic successor key generation algorithm KeyGen s , enter the public key pk, private key sk i-1 and label t, output the subsequent private key sk i , where sk i Able to decrypt any ciphertext except the one encrypted with tag t; S4. The medical center runs the probabilistic modifier key generation algorithm KeyGen m , input the master private key msk and attribute set S, output the private key sk; S5. The data owner runs the probabilistic encryption algorithm Enc, inputting the public key pk, identity id, message m and label list {t i } i∈[d] , output ciphertext c; S6. The miner runs the probabilistic block generation algorithm BlkGen, inputs the master public key mpk, and accesses the structure and Cipher Texts Output block message m blk,0 ; S7. The miner runs the probabilistic block increment algorithm BlkApp, inputs the master public key mpk, and accesses the structure The hash value h of the previous block i-1 and Cipher Texts Output block message m blk,i ; S8. The data modifier runs the deterministic block modification algorithm BlkMod, inputs the master public key mpk, private key sk, and ciphertext set and block message m blk,i , output block message m blk,i ; S9. The data modifier runs the deterministic block deletion algorithm BlkRem, inputting the master public key mpk, the private key sk and two block messages m blk,i ,m blk,i+1 , output message in Indicates the i-th block deleted; S10. The data user runs the deterministic verification algorithm Ver, inputting the ciphertext c and its related block message m blk,i , output bit b∈{0,1}, where b=1 if the ciphertext c is a valid message in the blockchain, otherwise b=0; S11. The data user runs the deterministic decryption algorithm Dec and inputs the public key pk and private key sk i , ciphertext c and label list {t i } i∈[d] , output plaintext m.

2. An editable medical blockchain system with privacy protection function as claimed in claim 1, characterized in that: The step S1 specifically includes: The medical center first selects a bilinear map in are all multiplicative cyclic groups of prime order p, g is the generator, and the generating parameters are Then select a random number Output master private key msk = a, master public key mpk = (1 λ ,g,u,h,w,v,e(g,g) a ).

3. An editable medical blockchain system with privacy protection function as claimed in claim 1, characterized in that: In step S2, the medical center runs the probabilistic initial key generation algorithm KeyGen i , generate the public key pk and the initial private key sk0, including: HC Selection Standard Collusion-Resistant Hash Function and random numbers Then set g1 = g α ,g2=g β and a d-degree polynomial q(·) subject to the constraint q(0) = β, defining a function V(x) = g q(x) , let t0 be a marker that is not used during the normal operation of the algorithm, and calculate K 0.2 =V(H(t0)) r ,K 0.3 =g r ,K 0,4 = t0, return the public key pk = (g1, g2, g q(1) ,...,g q(d) ) and private key sk0=(K 0.1 ,K 0.2 ,K 0.3 ,K 0.4 ).

4. An editable medical blockchain system with privacy protection function as claimed in claim 1, characterized in that: In step S3, the data user runs the probabilistic successor key generation algorithm KeyGen s , output the subsequent private key sk i , specifically including: DU random selection calculate Returns the private key sk i =(sk' u ,sk1,...,sk i-1 ,sk i ).

5. An editable medical blockchain system with privacy protection function as claimed in claim 1, characterized in that: The step S4 is a probabilistic modifier key generation algorithm, which outputs the private key sk, specifically including: The medical center runs the algorithm to parse the attribute set Random Selection And calculate K0 = g a w r and K1 = g r , for all τ∈[k], calculate and Return private key sk=(S,K0,K1,{K τ,2 ,K τ,3 } τ∈[k] ); In step S5, the data owner encrypts the message m to generate the ciphertext c, which specifically includes: Data owner random selection Calculate C1 = m·e(g1,g2) s , C2=g s , C 3,1 =V(H(t1)) s ,...,C 3,d =V(H(t d )) s , return the ciphertext c = (id, (t1, ..., t d ),C1,C2,C 3,1 ,...,C 3,d ).

6. An editable medical blockchain system with privacy protection function as claimed in claim 1, characterized in that: In step S6, the miner runs a probabilistic block generation algorithm and outputs an initial block message m blk,0 , specifically including: Miners first parse a set of ciphertext Get (c1,c2,...,c k ), then the quadratic residual The subgroup of chooses a generator And select a random value x∈{1,2,...,q-1}, set Then it randomly selects a hash value h' in the hash domain and randomly selects where ctr0∈{0,1} 32 In the temporary domain, calculate Parsing access structure The message domain The encryption algorithm is then randomly selected calculate Random Selection Calculate C = x·e(g,g) at and C0 = g t , for all τ∈[l], calculate and Return block information 7. An editable medical blockchain system with privacy protection function as claimed in claim 1, characterized in that: In step S7, the miner runs the probabilistic block increment algorithm and outputs an incremented block message m blk,i , specifically including: Miners first parse a set of ciphertext Get (c1,c2,...,c k ), then the quadratic residual The subgroup of chooses a generator And select a random value x∈{1,2,...,q-1}, set Random Selection where ctr i ∈{0,1} 32 In the temporary domain, calculate Parsing access structure The message domain The encryption algorithm is then randomly selected calculate Random Selection Calculate C = x·e(g,g) at and C0 = g t , for all τ∈[l], calculate and Return block information 8. An editable medical blockchain system with privacy protection function as claimed in claim 1, characterized in that: In step S8, the data modifier runs the probabilistic block modification algorithm and outputs the modified block message m' blk,i , specifically including: Miners parse a set of ciphertext Calculate message domain The I-th line of the message is calculate Constants in Derived Restore x = C / B, and randomly select k∈{1,2,...,q-1}, and calculate Finally, the modified block message is returned 9. An editable medical blockchain system with privacy protection function as claimed in claim 1, characterized in that: In step S9, the data modifier runs a deterministic block deletion algorithm and outputs a message in Indicates the i-th block to be deleted, including: Miners parse a set of ciphertext Calculate message domain The I-th line of the message is calculate Constants in Derived Restore x=C / B of the i+1th block, and randomly select k∈{1,2,...,q-1} to calculate set up Return message 10. An editable medical blockchain system with privacy protection function as claimed in claim 1, characterized in that: In step S10, the data user runs a deterministic verification algorithm and outputs a bit b∈{0,1}, where b=1 if the ciphertext c is valid information in the blockchain, otherwise b=0, specifically including: DU receives ciphertext c and block message m blk,i After that, calculate If h=h', output 1, otherwise, output 0; In step S11, the data user runs a deterministic decryption algorithm to decrypt the ciphertext c into plaintext m, which specifically includes: DU receives the public key pk and private key sk i , ciphertext c and label list {t i } i∈[d] After that, calculate a set of coefficients w1,...,w d ,w * Make For all j∈{0,1,...,i}, calculate Return message

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