BLOCKCHAIN-BASED SUPERVISION METHOD FOR ELECTRONIC IMMUNITY PASSPORT

Abstract

The invention provides a blockchain-based supervision method for an electronic immunity passport. A certificate authority generates and correspondingly distributes public-private key pairs. A hospital generates an immunity passport for a vaccine and assigns a passport number; encrypts the immunity passport and the passport number; and generates and uploads a transaction to a national alliance chain node (NACN). The NACN generates and uploads a second transaction to a world alliance chain (WAC). When the vaccine is requested to show the immunity passport, the vaccinee provides the passport number, generates and uploads a trapdoor to the WAC. The vaccine decrypts received ciphertext from the WAC to obtain plaintext data. An alliance chain node performs periodic maintenance by a smart contract. The invention can ensure data openness, traceability, and immutability, achieve effective supervision for the immunity passport data, provide reliable immunity passport data, and achieve search and regular maintenance for the immunity passport.

Description

TECHNICAL FIELD

The present invention provides a blockchain-based supervision method for an electronic immunity passport, which relates to the technical fields such as blockchain, consensus algorithms, and data security protection.

BACKGROUND

After the global outbreak of COVID-19 pandemic, exit-entry control policies have been tightened around the world, restricting cross-border flow. The spread of the epidemic has brought a great impact on the development of international communication and international trade and economic activities. In order to restore and develop the economy, relieve the pressure on people's livelihood, and restore normal production and international communication, countries and regions successively propose issuing immunity passports.

However, the immunity passports have some problems. Due to the difference between different vaccine types, the different vaccination methods in different countries, and the time interval between multiple doses of the vaccine, disagreement has arisen among countries over the reliability of the immunity passports, increasing the difficulty of unified management.

On the other hand, it is also necessary to determine the minimum length of immunity after vaccination and to monitor its duration, so as to know whether and when it is required to reassess the immune status of a passport holder and update his/her passport. Moreover, the immunity passport has problems of forgery and privacy leakage of personal information data.

These are the issues that should be considered and addressed during the design and use of the immunity passport.

SUMMARY

The present invention provides a blockchain-based supervision method for an electronic immunity passport, which solves the problems that the immunity passport data is not shared and its reliability needs to be ensured by means of blockchain and searchable encryption technologies, and achieves secure mutual recognition and communication of immunity passports between countries, so as to promote international exchange and gradual recovery of international trade and economic activities.

A blockchain-based supervision method for an electronic immunity passport is provided, which includes the following steps:

• • S1. initializing, by a certificate authority (CA), common parameters CP according to safety parameters; and generating public-private key pairs corresponding to various members, including a vaccinee i, a hospital h, a national alliance chain node c and a world alliance chain node w, in a blockchain system, and correspondingly distributing these key pairs;
  • S2. after the vaccinee i is vaccinated in the hospital h, generating, by the hospital h, an immunity passport m for the vaccinee i and assigning a passport number PUID_i;
  • S3. encrypting, by the hospital h, the immunity passport m and the passport number PUID_i, generating a hash value H₁(C₁) of ciphertext C₁ of the immunity passport m, and uploading the ciphertext C₁ of the immunity passport m to a hospital server for storage;
  • S4. generating, by the hospital h, a transaction T_C by means of the ciphertext hash value H₁(C₁), a keyword index I_K, and the date of expiry T of the immunity passport; and uploading the transaction T_C to the national alliance chain node;
  • S5. establishing, by the national alliance chain node, a safety index I_S by means of searchable encryption technology, generating a transaction T_W according to the safety index I_S and the date of expiry T, and uploading the transaction T_W to the world alliance chain;
  • S6. when the vaccinee i is requested to show the immunity passport m, generating, by the vaccinee i, a trapdoor T_Q by means of searchable encryption technology and according to the passport number PUID_i, and then uploading the trapdoor T_Q to the world alliance chain as a transaction;
  • S7. after receiving the trapdoor T_Q, searching, by the world alliance chain, for the ciphertext C₁ of the corresponding immunity passport m by means of a smart contract, and sending the found ciphertext C₁ of the immunity passport m to the vaccinee i;
  • S8. decrypting, by the vaccinee i, the received ciphertext C₁ of the immunity passport to obtain plaintext data m of the immunity passport;
  • S9. performing, by an alliance chain node, including a national alliance chain node and a world alliance chain node, periodic maintenance by means of a smart contract; checking whether the immunity passport m expires; and updating the expired immunity passport m.

Further, step S1 is specifically as follows:

• • S11. selecting, by the CA, two multiplicative cyclic groups G₁ and G₂ of which the order is a prime p according to the input safety parameter λ, a generating element being g∈G₁; defining bilinear mapping e: G₁×G₁→G₂; setting three collision-proof hash functions: H₁: {0,1}*→Z*_p, H₂: {0,1}*→G₁, H₃: G₂→{0,1}*; and issuing the common parameters CP={p, g, e, H₁, H₂, H₃};
  • S12. randomly selecting, by the CA, x_i∈Z*_p as a private key sk_i of the vaccinee i, and calculating the corresponding public key pk_i=g^xi; randomly selecting x_h∈Z*_p as a private key sk_h of the hospital h, and calculating the corresponding key pk_c=g^xc; randomly selecting x_c∈Z*_p as a private key sk_c of the national alliance chain node c and calculating the corresponding key pk_c=g^xc; and randomly selecting x_w ∈Z*_p as a private key sk_w of the world alliance chain node w and calculating the corresponding key pk_w=g^xw; and
  • S13. correspondingly assigning, by the CA through a secure channel, the public-private key pairs obtained in step S12 to the members, including the vaccinee i, the hospital h, the national alliance chain node c and the world alliance chain node w, in the blockchain system.

Further, in step S2, the immunity passport m includes personal information and vaccination information of a user, the vaccination information including vaccination time, vaccination location, and vaccine information.

Further, in step S3, the hospital h encrypting the immunity passport m and the passport number PUID_i is specifically as follows: randomly selecting, by the hospital h, a secrete value θ∈Z*_p, where Z*_p is the remainder class of the integer module p, that is, Z*_p={1,2, . . . , p-1}; calculating A=pk_i^θ, k=e(g^θ,H₂(PUID_i)), B=k×m, and F=H₃(k), where pk_i is the public key of the vaccinee i, e is the bilinear mapping defined in step S11, g is the generating element of G₁, G₁ is the multiplicative cyclic group of which the order is a prime p, H₂ and H₃ are two collision-proof hash functions, and m is the plaintext data of the immunity passport; and recording C₁=(A,B) as the ciphertext of the immunity passport m and C₂=(A,F) as the ciphertext of the immunity passport number PUID_i.

Further, in step S4, the hospital h generating the transaction T_C by means of the hash value of the ciphertext H₁(C₁), the keyword index I_K, and the date of expiry T of the immunity passport and uploading the transaction T_C to the national alliance chain node is specifically as follows:

• • S41. establishing, by the hospital h, a keyword index I_K=C by means of searchable encryption technology and according to the ciphertext C₂ of the immunity passport number PUID_i;
  • S42. generating, by the hospital h, a transaction T_C by means of the hash value H₁(C₁) of the ciphertext of the immunity passport m, the date of expiry T of the immunity passport, and the keyword index I_K; and
  • S43. packing, by the hospital h, the transaction T_C and uploading the same to the national alliance chain node; and running, by the national alliance chain node, a PBFT consensus mechanism to authenticate the transaction T_C, and generating a new block Block_C after successful authentication.

Further, in step S5, the national alliance chain node establishing a safety index I_S by means of searchable encryption technology, generating a transaction T_W according to the safety index I_S and the date of expiry T, and uploading the transaction T_W to the world alliance chain is specifically as follows:

• • S51. in each national alliance chain, extracting, by the national alliance chain node, a keyword index I_K, the data of expiry T, and a block identifier BID of the national alliance chain where the node is located from each transaction in the block Block_C generated in step S43;
  • S52. establishing a safety index I_S=BID,I_K by means of the keyword index I_K and the national alliance chain block identifier BID;
  • S53. generating, by the national alliance chain node, a transaction T_W by means of the safety index I_S and the date of expiry T; and
  • S54. packing and uploading, by the national alliance chain node, the transaction T_W to the world alliance chain; and running, by the world alliance chain node, a PBFT consensus mechanism to authenticate the transaction, and generating a new block Block_W after successful authentication.

Further, in step S6, the vaccinee i generating the trapdoor T_Q by means of searchable encryption technology and according to the passport number PUID_i when the vaccinee i is requested to show the immunity passport m, and then uploading the trapdoor T_Q to the world alliance chain as a transaction is specifically as follows:

• • S61. when the vaccinee i is requested to show the immunity passport m, randomly selecting, by the vaccinee i, a secrete value d∈Z*_p, where Z*p={1,2, . . . , p-1}; and calculating τ₁=

${H_2\left({\mathrm{PUID}}_i\right)}^{\frac{1}{{\mathrm{sk}}_i}}{\mathrm{pk}}_w^d$

and τ₂=g^d by means of his/her own passport number PUID_i, where sk_i is a private key of the vaccinee i, pk_w is a public key of the world alliance chain node w, H₂ is a harsh function defined in step S11, and g is a generating element of G₁; and

• • S62. generating a trapdoor T_Q=τ₁, τ₂, where τ₁ and τ₂ are parameters calculated in step S61; and then uploading the trapdoor T_Q to the world alliance chain as a transaction.

Further, in step S7, the world alliance chain searching for the ciphertext C₁ of the corresponding immunity passport m by means of a smart contract after receiving the trapdoor T_Q, and sending the found ciphertext C₁ of the immunity passport m to the vaccinee i is specifically as follows:

• • S71. after receiving the trapdoor T_Q=τ₁, τ₂, calculating, by the world alliance chain node,

$\frac{{\tau }_1}{{{\tau }_2}^{{\mathrm{sk}}_w}},$

where sk_w is a private key of the world alliance chain node w, and

${\tau }_1={H_2\left({\mathrm{PUID}}_i\right)}^{\frac{1}{{\mathrm{sk}}_i}}{\mathrm{pk}}_w^d$

and τ₂=g^d are parameters calculated in step S61;

• • S72. extracting, by the world alliance chain node, the safety index I_S=BID, I_K from the transaction T_W in the block Block_W generated in step S54, to authenticate whether the equation

$F=H_3\left(e\left(A,\frac{{\tau }_1}{{{\tau }_2}^{{\mathrm{sk}}_w}}\right)\right)$

holds true, where BID is the national alliance chain block identifier, I_K=C₂ is the keyword index, C₂=(A,F) is the ciphertext of the immunity passport number PUID_i, A=pk_i^θ and F=H₃(k) are parameters calculated in step S3, k=e(g^θ, H₂(PUID_i)), sk_w is the private key of the world alliance chain node w, τ₁ and τ₂ are parameters calculated in step S61, and e is the bilinear mapping defined in step S11; and if the equation holds true, extracting the country ID and the national alliance chain block identifier BID from the transaction T_W;

• • S73. finding the corresponding national alliance chain according to the country ID;
  • S74. in the national alliance chain, accessing the corresponding block by means of the national alliance chain block identifier BID;
  • S75. extracting the hash value H₁(C₁) of the ciphertext C₁ of the immunity passport m and the hospital ID from the block;
  • S76. finding a corresponding hospital server according to the hospital ID, and performing hash-value comparison to obtain the ciphertext C₁=(A,B) of the immunity passport m;
  • S77. returning the ciphertext C₁ of the immunity passport m to the alliance chain node; and
  • S78. sending, by the alliance chain node, the ciphertext C₁ of the immunity passport m to the vaccinee.

Further, in step S8, the vaccinee i decrypting the received ciphertext C₁ of the immunity passport to obtain plaintext data m of the immunity passport is as follows:

• • S81. receiving, by the vaccinee i, the ciphertext C₁=(A,B) of the immunity passport m, wherein A=pk_i^θ and B=k×m are parameters calculated in step S3, and k=e(g^θ,H₂(PUID_i)); and
  • S82. calculating the plaintext data

$m=\frac{B}{{e\left(A,H_2\left({\mathrm{PUID}}_i\right)\right)}^{\frac{1}{{\mathrm{sk}}_i}}}$

of the immunity passport, where sk_i is the private key of the vaccinee i, and H₂ is the hash function defined in step S11.

Further, in step S9, the alliance chain node, including the national alliance chain node and the world alliance chain node, performing periodic maintenance by means of a smart contract, checking whether the immunity passport m expires, and updating the expired immunity passport m is specifically as follows:

• • S91. acquiring, by the alliance chain node, the data of expiry T of the immunity passport m from the transaction;
  • S92. acquiring, by the alliance chain node, the timestamp t of the transaction;
  • S93. acquiring, by the alliance chain node, the current time T_cur; and
  • S94. calculating T_cur−t; and if T_cur−t<T, it indicating that the current immunity passport m has not yet expired; or if T_cur−t>T, it indicating that the current immunity passport m has expired, and notifying the relevant hospital to reassess the immune status of the vaccinee i through the national alliance chain node and to update the immunity passport for the vaccinee.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic flowchart of a blockchain-based supervision method for an electronic immunity passport in an embodiment of the present invention;

FIG. 2 is a schematic illustrative diagram of a blockchain system in the embodiment;

FIG. 3 is a schematic illustrative diagram of an immunity passport in the embodiment;

FIG. 4 is a schematic illustrative structural diagram of a transaction T_C in the embodiment; and

FIG. 5 is a schematic illustrative structural diagram of a transaction T_W in the embodiment.

DETAILED DESCRIPTION OF THE INVENTION

A preferred embodiment of the present invention is described below with reference to the accompanying drawings.

Embodiment

As shown in FIGS. 1 and 2, a blockchain-based supervision method for an electronic immunity passport includes the following steps:

• • S1. A CA initializes common parameters CP according to safety parameters; and generates public-private key pairs corresponding to various members, including a vaccinee i, a hospital h, a national alliance chain node c and a world alliance chain node w, in a blockchain system, and correspondingly distributes these key pairs. Step S1 is specifically as follows:
  • S11. The CA selects two multiplicative cyclic groups G₁ and G₂ of which the order is a prime p according to the input safety parameter λ, where a generating element g∈G₁; defines bilinear mapping e: G₁×G₁→G₂; sets three collision-proof hash functions: H₁:{0,1}*→Z*_p, H₂: {0,1}*→G₁, H₃: G₂→{0,1}*; and issues the common parameters CP={p, g, e, H₁, H₂, H₃}.
  • S12. The CA randomly selects xi E Z as a private key sk_i of the vaccinee i, and calculates the corresponding public key pk_i=g^xi; randomly selects x_h∈Z*_p as a private key sk_h of the hospital h, and calculates the corresponding key pk_c=g^xc; randomly selects x_c ∈Z*_p as a private key sk_c of the national alliance chain node c and calculates the corresponding key pk_c=g^xc; and randomly selects x_w ∈Z*_p as a private key sk_w of the world alliance chain node w and calculates the corresponding key pk_w=g^xw.

S13. The CA correspondingly assigns, through a secure channel, the public-private key pairs obtained in step S12 to the members, including the vaccinee i, the hospital h, the national alliance chain node c and the world alliance chain node w, in the blockchain system.

S2. After the vaccinee i is vaccinated in the hospital h, the hospital h generates an immunity passport m for the vaccinee i and assigns a passport number PUID_i.

In step S2, as shown in FIG. 3, the immunity passport m includes personal information and vaccination information of a user, where the vaccination information includes vaccination time, vaccination location, and vaccine information; and the vaccine information includes the manufacturer, the type, date of expiry, and the number of vaccination doses.

S3. The hospital h encrypts the immunity passport m and the passport number PUID_i, generates a hash value H₁(C₁) of the ciphertext C₁ of the immunity passport m, and uploads the ciphertext C₁ of the immunity passport m to a hospital server for storage.

In step S3, the hospital h encrypting the immunity passport m and the passport number PUID_i is specifically as follows: The hospital h randomly selects a secrete value θ∈Z*_p, where Z*_p is the remainder class of the integer module p, that is, Z*_p={1,2, . . . , p-1}; calculates A=pk_i^θ, k=e(g^θ, H₂(PUID_i)), B=k×m, and F=H₃(k), where pk_i is the public key of the vaccinee i, e is the bilinear mapping defined in step S11, g is the generating element of G₁, G₁ is the multiplicative cyclic group of which the order is a prime p, H₂ and H₃ are two collision-proof hash functions, and m is the plaintext data of the immunity passport; and records C₁=(A,B) as the ciphertext of the immunity passport m and C₂=(A,F) as the ciphertext of the immunity passport number PUID_i.

S4. The hospital h generates a transaction T_C by means of the ciphertext hash value H₁(C₁), a keyword index I_K, and the date of expiry T of the immunity passport; and uploads the transaction T_C to the national alliance chain node. The specific operation is as follows:

S41. The hospital h establishes a keyword index I_KC₂ by means of searchable encryption technology and according to the ciphertext C₂ of the immunity passport number PUID_i.

S42. The hospital h generates a transaction T_C by means of the hash value H₁(C₁) of the ciphertext of the immunity passport m, the date of expiry T of the immunity passport, and the keyword index I_K. The structure of the transaction T_C is shown in FIG. 3.

S43. The hospital h packs the transaction T_C and uploads the same to the national alliance chain node. The national alliance chain node runs a PBFT consensus mechanism to authenticate the transaction T_C, and generates a new block Block_C after successful authentication.

S5. The national alliance chain node establishes a safety index I_S by means of searchable encryption technology, generates a transaction T_W according to the safety index I_S and the date of expiry T, and uploads the transaction T_W to the world alliance chain. The specific operation is as follows:

S51. In each national alliance chain, the national alliance chain node extracts a keyword index I_K, the data of expiry T, and a block identifier BID of the national alliance chain where the node is located from each transaction in the block Block_C generated in step S43.

S52. A safety index I_S=BID, I_K is established by means of the keyword index I_K and the national alliance chain block identifier BID.

S53. The national alliance chain node generates a transaction T_W by means of the safety index I_S and the date of expiry T, where the structure of the transaction T_W is shown in FIG. 4.

S54. The national alliance chain node packs and uploads the transaction T_W to the world alliance chain; and the world alliance chain node runs a PBFT consensus mechanism to authenticate the transaction, and generates a new block Block_W after successful authentication.

S6. When the vaccinee i is requested to show the immunity passport m, for example, when the vaccinee i needs to go abroad and is requested to show the immunity passport m, the vaccinee i generates a trapdoor T_Q by means of searchable encryption technology and according to the passport number PUID_i, and then uploads the trapdoor T_Q to the world alliance chain as a transaction. The specific operation is as follows:

S61. When the vaccinee i is requested to show the immunity passport m, the vaccinee i randomly selects a secrete value d∈Z*_p, where Z*_p={1,2, . . . , p-1}; and calculates

${\tau }_1={H_2\left({\mathrm{PUID}}_i\right)}^{\frac{1}{{\mathrm{sk}}_i}}{\mathrm{pk}}_w^d$

and τ₂=g^d by means of his/her own passport number PUID_i, where sk_i is a private key of the vaccinee i, pk_w is a public key of the world alliance chain node w, H₂ is a harsh function defined in step S11, and g is a generating element of G₁.

S62. A trapdoor T_Q=τ₁, τ₂ is generated, where τ₁ and τ₂ are parameters calculated in step S61; and then the trapdoor T_Q is uploaded to the world alliance chain as a transaction.

S7. After receiving the trapdoor T_Q, the world alliance chain searches for the ciphertext C₁ of the corresponding immunity passport m by means of a smart contract, and sends the found ciphertext C₁ of the immunity passport m to the vaccinee i. The specific operation is as follows:

S71. After receiving the trapdoor T_Q=τ₁, τ₂, the world alliance chain node calculates

$\frac{{\tau }_1}{{{\tau }_2}^{{\mathrm{sk}}_w}},$

where sk_w is a private key of the world alliance chain node w, and

${\tau }_1={H_2\left({\mathrm{PUID}}_i\right)}^{\frac{1}{{\mathrm{sk}}_i}}{\mathrm{pk}}_w^d$

and τ₂=g^d are parameters calculated in step S61.

S72. The world alliance chain node extracts the safety index I_S=BID, I_K from the transaction T_W in the block Block_W generated in step S54, to authenticate whether the equation

$F=H_3\left(e\left(A,\frac{{\tau }_1}{{{\tau }_2}^{{\mathrm{sk}}_w}}\right)\right)$

holds true, where BID is the national alliance chain block identifier, I_K=C₂ is the keyword index, C₂=(A,F) is the ciphertext of the immunity passport number PUID_i, A=pk_i^θ and F=H₃(k) are parameters calculated in step S3, k=e(g^θ, H₂(PUID_i)), sk_w is the private key of the world alliance chain node w, τ₁ and τ₂ are parameters calculated in step S61, and e is the bilinear mapping defined in step S11. If the equation holds true, the country ID and the national alliance chain block identifier BID are extracted from the transaction T_W.

S73. The corresponding national alliance chain is found according to the country ID.

S74. In the national alliance chain, the corresponding block is accessed by means of the national alliance chain block identifier BID.

S75. The hash value H₁(C₁) of the ciphertext C₁ of the immunity passport m and the hospital ID are extracted from the block.

S76. A corresponding hospital server is found according to the hospital ID, and hash-value comparison is performed to obtain the ciphertext C₁=(A,B) of the immunity passport m.

S77. The ciphertext C₁ of the immunity passport m is returned to the alliance chain node.

S78. The alliance chain node sends the ciphertext C₁ of the immunity passport m to the vaccinee.

S8. The vaccinee i decrypts the received ciphertext C₁ of the immunity passport to obtain plaintext data m of the immunity passport. The specific operation is as follows:

S81. The vaccinee i receives the ciphertext C₁=(A,B) of the immunity passport m, where A=pk_i^θ and B=k×m are parameters calculated in step S3, and k=e(g^θ, H₂(PUID_i)).

S82. The plaintext data

$m=\frac{B}{{e\left(A,H_2\left({\mathrm{PUID}}_i\right)\right)}^{\frac{1}{{\mathrm{sk}}_i}}}$

of the immunity passport is calculated, where sk_i is the private key of the vaccinee i, and H₂ is the hash function defined in step S11.

S9. An alliance chain node, including a national alliance chain node and a world alliance chain node, performs periodic maintenance by means of a smart contract; checks whether the immunity passport m expires; and updates the expired immunity passport m. The specific operation is as follows:

S91. The alliance chain node acquires the data of expiry T of the immunity passport m from the transaction.

S92. The alliance chain node acquires the timestamp t of the transaction.

S93. The alliance chain node acquires the current time T_cur.

S94. T_cur−t is calculated. If T_cur−t<T, it indicates that the current immunity passport m has not yet expired; or if T_cur−t>T, it indicates that the current immunity passport m has expired, and the relevant hospital is notified to reassess the immune status of the vaccinee i through the national alliance chain node and to update the immunity passport for the vaccinee.

The blockchain-based supervision method for an electronic immunity passport in the embodiment includes the following six entities:

Vaccinee: After being vaccinated, the vaccinee generates his/her immunity passport via a user terminal and acquires his/her own immunity passport number. When the vaccinee plans to go abroad, he/she provides his/her own immunity passport number to an inspector for query, to obtain the ciphertext of the immunity passport and decrypt the ciphertext.

Hospital: After vaccinating the vaccinee against COVID-19, the hospital generates an immunity passport for the vaccinee through a terminal device and encrypts the passport, and uploads the ciphertext data of the immunity passport to the hospital server for storage.

Hospital server: The hospital server stores the ciphertext data of the immunity passport of the vaccinee.

National alliance chain: Each country separately maintains a corresponding national alliance chain which is led by the National Health Commission. The domestic hospitals serve as the national alliance chain nodes and adopt a PBFT consensus mechanism.

World alliance chain: The countries all over the world work together to maintain one world alliance chain which is led by the World Health Organization. The health commission in each country and the international health organizations serve as the world alliance chain nodes and adopt a PBFT consensus mechanism.

Certificate Authority CA: As a trusted third party, the CA initializes common parameters, and generates and distributes keys for each member in the scheme.

The blockchain-based supervision method for an electronic immunity passport stores relevant data, such as indexes and the date of expiry of the immunity passport, by means of blockchain technology, thus ensuring data openness, traceability, and unalterableness, and achieving openness and transparency of the relevant data such as indexes and the date of expiry of the immunity passport. In this way, the immunity passport data can be effectively supervised, and reliable immunity passport data can be provided for the vaccinee, thus achieving secure mutual recognition and communication of the immunity passport between countries, providing convenience for the vaccine, and further avoiding the problems of the forgery of immunity passport data and privacy leakage of personal information data. The method further completes search and regular maintenance for the immunity passport by means of the smart contract of the blockchain.

The blockchain-based supervision method for an electronic immunity passport guarantees data confidentiality by means of searchable encryption technology, implements sharing of the immunity passport data, and further solves the problems of privacy leakage and forgery of personal information data with reference to the cryptographic technique. For the dates of expiry of the vaccine and the immunity passport, the method supervises the transactions on the alliance chain by using smart contract and timestamp technologies, and detects the date of expiry of the immunity passport, so as to know whether and when it is required to reassess the immune status of a passport holder, and to update his/her passport.

The Present Invention has the Following Advantageous Effects:

• • 1. The blockchain-based supervision method for an electronic immunity passport stores relevant data, such as indexes and the date of expiry of the immunity passport, by means of blockchain technology, thus ensuring data openness, traceability, and immutability. In this way, the immunity passport data can be effectively supervised, and reliable immunity passport data can be provided for the vaccinee, thus achieving secure mutual recognition and communication of the immunity passport between countries, providing convenience for the vaccinee, and further avoiding the problems of forgery of the immunity passport data and privacy leakage of personal information data. The method further completes search and regular maintenance for the immunity passport by means of the smart contract of the blockchain.
  • 2. The blockchain-based supervision method for an electronic immunity passport guarantees data confidentiality by means of searchable encryption technology, implements sharing of the immunity passport data, and further solves the problems of privacy leakage and forgery of personal information data with reference to the cryptographic technique.
  • 3. For the dates of expiry of the vaccine and the immunity passport, the present invention supervises the transactions on the alliance chain by using smart contract and timestamp technologies, and detects the date of expiry of the immunity passport, so as to know whether and when it is required to reassess the immune status of a passport holder and to update his/her passport.
  • 4. In the blockchain-based supervision method for an electronic immunity passport, the immunity passport records personal information and vaccination information of a user, thus facilitating recovery of normal production and life, international contacts and international trade and economic activities.

Although the present invention has been described in detail above with reference to the foregoing embodiment, persons skilled in the art still can modify the technical solutions described in the foregoing embodiment, or make equivalent substitutions for some of the technical features. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A blockchain-based supervision method for an electronic immunity passport, comprising the following steps: S1. initializing, by a certificate authority (CA), common parameters CP according to safety parameters; and generating public-private key pairs corresponding to various members, including a vaccinee i, a hospital h, a national alliance chain node c and a world alliance chain node w, in a blockchain system, and correspondingly distributing these key pairs;S2. after the vaccinee i is vaccinated in the hospital h, generating, by the hospital h, an immunity passport m for the vaccinee i and assigning a passport number PUIDi;S3. encrypting, by the hospital h, the immunity passport m and the passport number PUIDi, generating a hash value H1(C1) of ciphertext C1 of the immunity passport m, and uploading the ciphertext C1 of the immunity passport m to a hospital server for storage;S4. generating, by the hospital h, a transaction TC by means of the ciphertext hash value H1(C1), a keyword index IK, and the date of expiry T of the immunity passport; and uploading the transaction TC to the national alliance chain node;S5. establishing, by the national alliance chain node, a safety index IS by means of searchable encryption technology, generating a transaction TW according to the safety index IS and the date of expiry T, and uploading the transaction TW to the world alliance chain;S6. when the vaccinee i is requested to show the immunity passport m, generating, by the vaccinee i, a trapdoor TQ by means of searchable encryption technology and according to the passport number PUIDi, and then uploading the trapdoor TQ to the world alliance chain as a transaction;S7. after receiving the trapdoor TQ, searching, by the world alliance chain, for the ciphertext C1 of the corresponding immunity passport m by means of a smart contract, and sending the found ciphertext C1 of the immunity passport m to the vaccinee i;S8. decrypting, by the vaccinee i, the received ciphertext C1 of the immunity passport to obtain plaintext data m of the immunity passport; andS9. performing, by an alliance chain node, including a national alliance chain node and a world alliance chain node, periodic maintenance by means of a smart contract; checking whether the immunity passport m expires; and updating the expired immunity passport m.

2. The blockchain-based supervision method for an electronic immunity passport of claim 1, wherein the step S1 is specifically as follows: S11. selecting, by the CA, two multiplicative cyclic groups G1 and G2 of which the order is a prime p according to the input safety parameter λ, a generating element being g E G1; defining bilinear mapping e: G1×G1→G2; setting three collision-proof hash functions: H1: {0,1}*→Z*p, H2: {0,1}*→G1, H3: G2→{0,1}*; and issuing the common parameters CP={p, g, e, H1, H2, H3};S12. randomly selecting, by the CA, xi∈Z*p as a private key ski of the vaccinee i, and calculating the corresponding public key pk1=gxi; randomly selecting xh∈Z*p as a private key skh of the hospital h, and calculating the corresponding key pkc=gxc; randomly selecting xc ∈Z*p as a private key skc of the national alliance chain node c and calculating the corresponding key pkc=gxc; and randomly selecting xW ∈Z*p as a private key skw of the world alliance chain node w and calculating the corresponding key pkw=gxw; andS13. correspondingly assigning, by the CA through a secure channel, the public-private key pairs obtained in step S12 to the members, including the vaccinee i, the hospital h, the national alliance chain node c and the world alliance chain node w, in the blockchain system.

3. The blockchain-based supervision method for an electronic immunity passport of claim 1, wherein in the step S2, the immunity passport m comprises personal information and vaccination information of a user, the vaccination information comprising vaccination time, vaccination location, and vaccine information.

4. The blockchain-based supervision method for an electronic immunity passport of claim 2, wherein in the step S3, the hospital h encrypting the immunity passport m and the passport number PUIDi is specifically as follows: randomly selecting, by the hospital h, a secrete value θ∈Z*p, wherein Z*p is the remainder class of the integer module p, that is, Z*p={1,2, . . . , p-1}; calculating A=pkiθ, k=e(gθ, H2(PUIDi)), B=k×m, and F=H3(k), wherein pki is a public key of the vaccinee i, e is the bilinear mapping defined in step S11, g is the generating element of G1, G1 is the multiplicative cyclic group of which the order is a prime p, H2 and H3 are two collision-proof hash functions, and m is the plaintext data of the immunity passport; and recording C1=(A,B) as the ciphertext of the immunity passport m and C2=(A,F) as the ciphertext of the immunity passport number PUIDi.

5. The blockchain-based supervision method for an electronic immunity passport of claim 1, wherein in the step S4, the hospital h generating the transaction TC by means of the ciphertext hash value H1(C1), the keyword index IK, and the date of expiry T of the immunity passport and uploading the transaction TC to the national alliance chain node is specifically as follows: S41. establishing, by the hospital h, a keyword index IK=C2 by means of searchable encryption technology and according to the ciphertext C2 of the immunity passport number PUIDi;S42. generating, by the hospital h, a transaction TC by means of the hash value H1(C1) of the ciphertext of the immunity passport m, the date of expiry T of the immunity passport, and the keyword index IK; andS43. packing, by the hospital h, the transaction TC and uploading the same to the national alliance chain node; and running, by the national alliance chain node, a PBFT consensus mechanism to authenticate the transaction TC, and generating a new block BlockC after successful authentication.

6. The blockchain-based supervision method for an electronic immunity passport of claim 1, wherein in the step S5, the national alliance chain node establishing a safety index IS by means of searchable encryption technology, generating a transaction TW according to the safety index IS and the date of expiry T, and uploading the transaction TW to the world alliance chain is specifically as follows: S51. in each national alliance chain, extracting, by the national alliance chain node, a keyword index IK, the data of expiry T, and a block identifier BID of the national alliance chain where the node is located from each transaction in the block BlockC generated in step S43;S52. establishing a safety index IS=BID, IK by means of the keyword index IK and the national alliance chain block identifier BID;S53. generating, by the national alliance chain node, a transaction TW by means of the safety index IS and the date of expiry T; andS54. packing and uploading, by the national alliance chain node, the transaction TW to the world alliance chain; and running, by the world alliance chain node, a PBFT consensus mechanism to authenticate the transaction, and generating a new block BlockW after successful authentication.

7. The blockchain-based supervision method for an electronic immunity passport of claim 2, wherein in the step S6, the vaccinee i generating the trapdoor TQ by means of searchable encryption technology and according to the passport number PUID1 when the vaccinee i is requested to show the immunity passport m, and then uploading the trapdoor TQ to the world alliance chain as a transaction is specifically as follows: S61. when the vaccinee i is requested to show the immunity passport m, randomly selecting, by the vaccinee i, a secrete value d∈Z*p, wherein Z*p={1,2, . . . , p-1}; and calculating

8. The blockchain-based supervision method for an electronic immunity passport of claim 6, wherein in the step S7, the world alliance chain searching for the ciphertext C1 of the corresponding immunity passport m by means of a smart contract after receiving the trapdoor TQ, and sending the found ciphertext C1 of the immunity passport m to the vaccinee i is specifically as follows: S71. after receiving the trapdoor TQ=τ1, τ2, calculating, by the world alliance chain node,

9. The blockchain-based supervision method for an electronic immunity passport of claim 4, wherein in the step S8, the vaccinee i decrypting the received ciphertext C1 of the immunity passport to obtain plaintext data m of the immunity passport is as follows: S81. receiving, by the vaccinee i, the ciphertext C1=(A,B) of the immunity passport m, wherein A=pkiθ and B=k×m are parameters calculated in step S3, and k=e(gθ,H2(PUIDi)); andS82. calculating the plaintext data

10. The blockchain-based supervision method for an electronic immunity passport of claim 1, wherein in step S9, the alliance chain node, including the national alliance chain node and the world alliance chain node, performing periodic maintenance by means of a smart contract, checking whether the immunity passport m expires, and updating the expired immunity passport m is specifically as follows: S91. acquiring, by the alliance chain node, the data of expiry T of the immunity passport m from the transaction;S92. acquiring, by the alliance chain node, the timestamp t of the transaction;S93. acquiring, by the alliance chain node, the current time Tcur; andS94. calculating Tcur−t; and if Tcur−t<T, it indicating that the current immunity passport m has not yet expired; or if Tcur−t>T, it indicating that the current immunity passport m has expired, and notifying the relevant hospital to reassess the immune status of the vaccinee i through the national alliance chain node and to update the immunity passport for the vaccinee.

11. The blockchain-based supervision method for an electronic immunity passport of claim 2, wherein in the step S4, the hospital h generating the transaction TC by means of the ciphertext hash value H1(C1), the keyword index IK, and the date of expiry T of the immunity passport and uploading the transaction TC to the national alliance chain node is specifically as follows: S41. establishing, by the hospital h, a keyword index IK=C2 by means of searchable encryption technology and according to the ciphertext C2 of the immunity passport number PUIDi;S42. generating, by the hospital h, a transaction TC by means of the hash value H1(C1) of the ciphertext of the immunity passport m, the date of expiry T of the immunity passport, and the keyword index IK; andS43. packing, by the hospital h, the transaction TC and uploading the same to the national alliance chain node; and running, by the national alliance chain node, a PBFT consensus mechanism to authenticate the transaction TC, and generating a new block BlockC after successful authentication.

12. The blockchain-based supervision method for an electronic immunity passport of claim 3, wherein in the step S4, the hospital h generating the transaction TC by means of the ciphertext hash value H1(C1), the keyword index IK, and the date of expiry T of the immunity passport and uploading the transaction TC to the national alliance chain node is specifically as follows: S41. establishing, by the hospital h, a keyword index IK=C2 by means of searchable encryption technology and according to the ciphertext C2 of the immunity passport number PUIDi;S42. generating, by the hospital h, a transaction TC by means of the hash value H1(C1) of the ciphertext of the immunity passport m, the date of expiry T of the immunity passport, and the keyword index IK; andS43. packing, by the hospital h, the transaction TC and uploading the same to the national alliance chain node; and running, by the national alliance chain node, a PBFT consensus mechanism to authenticate the transaction TC, and generating a new block BlockC after successful authentication.

13. The blockchain-based supervision method for an electronic immunity passport of claim 4, wherein in the step S4, the hospital h generating the transaction TC by means of the ciphertext hash value H1(C1), the keyword index IK, and the date of expiry T of the immunity passport and uploading the transaction TC to the national alliance chain node is specifically as follows: S41. establishing, by the hospital h, a keyword index IK=C2 by means of searchable encryption technology and according to the ciphertext C2 of the immunity passport number PUIDi;S42. generating, by the hospital h, a transaction TC by means of the hash value H1(C1) of the ciphertext of the immunity passport m, the date of expiry T of the immunity passport, and the keyword index IK; andS43. packing, by the hospital h, the transaction TC and uploading the same to the national alliance chain node; and running, by the national alliance chain node, a PBFT consensus mechanism to authenticate the transaction TC, and generating a new block BlockC after successful authentication.

14. The blockchain-based supervision method for an electronic immunity passport of claim 2, wherein in the step S5, the national alliance chain node establishing a safety index IS by means of searchable encryption technology, generating a transaction TW according to the safety index IS and the date of expiry T, and uploading the transaction TW to the world alliance chain is specifically as follows: S51. in each national alliance chain, extracting, by the national alliance chain node, a keyword index IK, the data of expiry T, and a block identifier BID of the national alliance chain where the node is located from each transaction in the block BlockC generated in step S43;S52. establishing a safety index IS=BID, IK by means of the keyword index IK and the national alliance chain block identifier BID;S53. generating, by the national alliance chain node, a transaction TW by means of the safety index IS and the date of expiry T; andS54. packing and uploading, by the national alliance chain node, the transaction TW to the world alliance chain; and running, by the world alliance chain node, a PBFT consensus mechanism to authenticate the transaction, and generating a new block BlockW after successful authentication.

15. The blockchain-based supervision method for an electronic immunity passport of claim 3, wherein in the step S5, the national alliance chain node establishing a safety index IS by means of searchable encryption technology, generating a transaction TW according to the safety index IS and the date of expiry T, and uploading the transaction TW to the world alliance chain is specifically as follows: S51. in each national alliance chain, extracting, by the national alliance chain node, a keyword index IK, the data of expiry T, and a block identifier BID of the national alliance chain where the node is located from each transaction in the block BlockC generated in step S43;S52. establishing a safety index IS=ID, IK by means of the keyword index IK and the national alliance chain block identifier BID;S53. generating, by the national alliance chain node, a transaction TW by means of the safety index IS and the date of expiry T; andS54. packing and uploading, by the national alliance chain node, the transaction TW to the world alliance chain; and running, by the world alliance chain node, a PBFT consensus mechanism to authenticate the transaction, and generating a new block BlockW after successful authentication.

16. The blockchain-based supervision method for an electronic immunity passport of claim 4, wherein in the step S5, the national alliance chain node establishing a safety index IS by means of searchable encryption technology, generating a transaction TW according to the safety index IS and the date of expiry T, and uploading the transaction TW to the world alliance chain is specifically as follows: S51. in each national alliance chain, extracting, by the national alliance chain node, a keyword index IK, the data of expiry T, and a block identifier BID of the national alliance chain where the node is located from each transaction in the block BlockC generated in step S43;S52. establishing a safety index IS=BID, IK by means of the keyword index IK and the national alliance chain block identifier BID;S53. generating, by the national alliance chain node, a transaction TW by means of the safety index IS and the date of expiry T; andS54. packing and uploading, by the national alliance chain node, the transaction TW to the world alliance chain; and running, by the world alliance chain node, a PBFT consensus mechanism to authenticate the transaction, and generating a new block BlockW after successful authentication.

17. The blockchain-based supervision method for an electronic immunity passport of claim 3, wherein in the step S6, the vaccinee i generating the trapdoor TQ by means of searchable encryption technology and according to the passport number PUIDi when the vaccinee i is requested to show the immunity passport m, and then uploading the trapdoor TQ to the world alliance chain as a transaction is specifically as follows: S61. when the vaccinee i is requested to show the immunity passport m, randomly selecting, by the vaccinee i, a secrete value d∈Z*p, wherein Z*p={1,2, . . . , p-1}; and calculating

18. The blockchain-based supervision method for an electronic immunity passport of claim 4, wherein in the step S6, the vaccinee i generating the trapdoor TQ by means of searchable encryption technology and according to the passport number PUID1 when the vaccinee i is requested to show the immunity passport m, and then uploading the trapdoor TQ to the world alliance chain as a transaction is specifically as follows: S61. when the vaccinee i is requested to show the immunity passport m, randomly selecting, by the vaccinee i, a secrete value d∈Z*p, wherein Z*p={1,2, . . . , p-1}; and calculating

19. The blockchain-based supervision method for an electronic immunity passport of claim 2, wherein in the step S9, the alliance chain node, including the national alliance chain node and the world alliance chain node, performing periodic maintenance by means of a smart contract, checking whether the immunity passport m expires, and updating the expired immunity passport m is specifically as follows: S91. acquiring, by the alliance chain node, the data of expiry T of the immunity passport m from the transaction;S92. acquiring, by the alliance chain node, the timestamp t of the transaction;S93. acquiring, by the alliance chain node, the current time Tcur; andS94. calculating Tcur−t; and if Tcur−t<T, it indicating that the current immunity passport m has not yet expired; or if Tcur−t>T, it indicating that the current immunity passport m has expired, and notifying the relevant hospital to reassess the immune status of the vaccinee i through the national alliance chain node and to update the immunity passport for the vaccinee.

20. The blockchain-based supervision method for an electronic immunity passport of claim 3, wherein in the step S9, the alliance chain node, including the national alliance chain node and the world alliance chain node, performing periodic maintenance by means of a smart contract, checking whether the immunity passport m expires, and updating the expired immunity passport m is specifically as follows: S91. acquiring, by the alliance chain node, the data of expiry T of the immunity passport m from the transaction;S92. acquiring, by the alliance chain node, the timestamp t of the transaction;S93. acquiring, by the alliance chain node, the current time Tcur; andS94. calculating Tcur−t; and if Tcur−t<T, it indicating that the current immunity passport m has not yet expired; or if Tcur−t>T, it indicating that the current immunity passport m has expired, and notifying the relevant hospital to reassess the immune status of the vaccinee i through the national alliance chain node and to update the immunity passport for the vaccinee.