Information encryption and its trusted deletion method and system

Abstract

The application relates to an information encryption and trusted deletion method and system, which comprises the following steps: dividing information fields into at least two sensitive levels based on the distinction of sensitive degrees; generating an encryption key and a key fragment thereof based on a preset threshold, establishing a mapping between a target and the key fragment, encrypting information fields of corresponding sensitive levels based on encryption keys of different sensitive levels, and deleting original information data; and in the case that a recovery request is received, the encryption key is recovered based on the key fragment and is decrypted to obtain original information data. The application realizes multi-party secure key deletion of encrypted personal information in the case that information is difficult to be safely stored and trusted deleted.

Description

Technical Field

[0001] This invention relates to the field of information security technology, and in particular to a method and system for information encryption and its trusted deletion. Background Technology

[0002] In today's internet environment, service providers are increasingly collecting users' personal information to provide better services. To protect this information, service providers may encrypt and store it. When personal information is encrypted, deleting it directly using the encryption key can largely ensure that the information is unrecoverable; this process is called encrypted deletion. Thus, encrypting personal information not only guarantees user privacy but also allows for more secure deletion through encrypted deletion.

[0003] However, the storage of encryption keys becomes a critical issue; if the key is corrupted, the original data cannot be recovered. To improve the reliability of key storage, a distributed storage approach can be used, storing multiple copies of the key across multiple nodes in the system. This way, if a single node fails, other nodes can still use the key copies to recover the encrypted data. Furthermore, in environments with high security requirements, after deleting all key copies, it is still necessary to delete the encrypted personal information to further ensure the irrecoverability of personal information.

[0004] While current encryption deletion methods generally guarantee the effectiveness of deletion, they still lack robust protection against unforeseen events. There are two main vulnerabilities in encrypted data storage: firstly, data loss due to server malfunction; and secondly, data theft due to server intrusion. For encrypted personal information, if the system stores only a single key, a single point of failure could result in key loss, making data recovery impossible. Furthermore, if the server is compromised, the risk of attack on a single node becomes too concentrated. After a server is compromised, the attacker can also use the key to obtain the original data, leading to privacy breaches. While storing key copies on multiple nodes can prevent the loss of encrypted data due to a single point of failure, an attacker can still recover the original data using the obtained key after compromising any node. Therefore, simply storing key copies on multiple nodes does not reduce the risk of intrusion.

[0005] For example, Chinese patent CN114629661A discloses a method for processing encrypted information. This method includes: encrypting shared information using a plaintext key to obtain ciphertext; encrypting the plaintext key according to a time trapdoor parameter to obtain a first key ciphertext; encrypting each leaf node according to the node index information of each leaf node in the access policy tree to obtain a leaf node ciphertext; processing the preset deletion time information and the time trapdoor parameter using a hash function to generate a time trapdoor; storing the access policy tree, the ciphertext of the shared information, the time trapdoor, the first key ciphertext, and the leaf node ciphertexts of each leaf node into different information blocks in the initial information chain to obtain a target information chain; sending the target information chain to a cloud server; generating a first information deletion request according to the preset deletion time information and the target private key; and sending the first information deletion request to a trusted authority. Clearly, in the event of a server malfunction, this information encryption and deletion process is prone to data loss, and the server is also vulnerable to attack, leading to data theft.

[0006] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method for information encryption and its trusted deletion, characterized in that the method includes at least:

[0008] Information fields are divided into at least two sensitivity levels based on their degree of sensitivity;

[0009] An encryption key and its key fragments are generated based on a preset threshold, and a mapping between the target and the key fragments is established.

[0010] Encrypt the information fields corresponding to different sensitivity levels using encryption keys of different sensitivity levels and delete the original information data;

[0011] Upon receiving a recovery request, the encryption key is recovered and decrypted based on the key fragments to obtain the original information data.

[0012] Preferably, the method further includes: during the process of deleting information of a specified sensitivity level, deleting the key fragment corresponding to the sensitivity level.

[0013] Preferably, the method further includes: during the process of deleting information of a specified sensitivity level, information fields whose own sensitivity level is higher than that of the deleted key fragment are restricted from access.

[0014] Preferably, the method further includes: the step of establishing the mapping between the target and the key fragment is performed based on a multi-party collaborative key management method.

[0015] Preferably, the steps of the multi-party collaborative key management method include at least:

[0016] In a scenario where n servers collaboratively manage an encryption key, the encryption key generates n key fragments based on a set threshold t; at least t of the key fragments are collected to recover the original key; the encryption key is randomly generated based on a preset sensitivity level; and the encryption key is fragmented to generate the key fragments.

[0017] Preferably, the step of fragmenting the encryption key includes at least: randomly generating t-1 coefficients a based on the threshold t. j Construct a polynomial of order t-1, f(x) = a t-1 x t-1 +…+a2x 2 +…+a1x 1 +K i Among them, K i Represents the encryption key, a t-1 Represents coefficient a j x represents a variable; n non-zero numbers x will be randomly generated. k Substituting into the t-1 polynomial, we can calculate (x) k ,f(x k The key is divided into n key fragments, where 1 ≤ k ≤ n. When t = n, each key will generate n fragments. Collect all n fragments to recover the original key.

[0018] Preferably, the step of recovering the encryption key based on the key fragments includes at least: selecting n random values ​​and marking the key fragments as... Perform an XOR operation on the key fragments The first result K obtained from the calculation m For L m Sensitive level encryption keys, To match the first result K m Corresponding key fragmentation; for key fragmentation Perform hash operation The second result obtained is labeled as XOR operation on n key fragments Let the third result be denoted as K. m-1 Third result K m-1 For L m-1 Sensitive level encryption keys, To be consistent with the third result K m-1 The corresponding key fragments. This invention also provides an information encryption and trusted deletion system, comprising at least a processor configured to: divide information fields into at least two sensitivity levels based on differences in sensitivity; generate encryption keys and key fragments based on preset threshold values, establish a mapping between the target and the key fragments, encrypt information fields of corresponding sensitivity levels using encryption keys of different sensitivity levels, and delete the original information data; upon receiving a recovery request, recover the encryption keys based on the key fragments and decrypt them to obtain the original information data.

[0019] Preferably, the processor is further configured to: delete the key fragment corresponding to the specified sensitivity level during the process of deleting information of a specified sensitivity level.

[0020] Preferably, the processor is further configured to:

[0021] During the deletion of information with a specified sensitivity level, information fields with a sensitivity level higher than that of the deleted key fragment are restricted from access.

[0022] This invention manages keys for encrypted personal information data in two ways. The first method categorizes personal information into fields of different sensitivity levels, each encrypted with a different key. When a user can access a field of a certain sensitivity level, they can also access all fields with lower sensitivity levels, but not vice versa. The second method involves distributed storage of keys for each sensitivity level to prevent key theft and leakage. For distributed storage, this invention provides two mechanisms. The first, for server clusters prone to single points of failure, uses an (n, t) threshold for key management. This means the key generates n key fragments, which are distributed to n servers. Collecting t key fragments is sufficient to recover the key. This method provides a degree of fault tolerance; even if a server experiences a single point of failure, the key can still be recovered. The second approach is for server clusters that are less prone to single points of failure. In this case, the key is divided into n key fragments and distributed to n servers. All n key fragments are needed to recover the key. If key fragments are fragmented in this way, it is only necessary to delete the key fragment on any one server to ensure that the key cannot be recovered. At the same time, low-sensitivity keys can be derived from high-sensitivity keys, which can reduce the storage space overhead of key fragments on the server. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a preferred embodiment of the information encryption and trusted deletion method provided by the present invention.

[0024] List of reference numerals

[0025] 10: Terminal; 20: First server; 30: Second server. Detailed Implementation

[0026] The following is a detailed explanation with reference to the accompanying drawings.

[0027] The following explanation is provided for certain terms and concepts in this invention.

[0028] Threshold: The threshold is the critical value at which the key can be recovered. For example, if the threshold is t, then the key can be recovered by collecting more than or equal to t key fragments.

[0029] Key fragmentation: Key fragmentation refers to a portion of the original key. The original key is divided into multiple parts using a specific algorithm, and each part is a key fragment of the original key.

[0030] Multi-party collaboration: Multi-party collaboration refers to the cooperation among multiple computing entities (such as computers, servers, etc.) to jointly complete a task.

[0031] This invention provides a method and system for information encryption and trusted deletion, an information security management system and method, and an information recovery method and system.

[0032] The system of the present invention can be an information encryption and trusted deletion system, an information security management system, or an information recovery system.

[0033] The system of the present invention includes at least a processor. The processor includes a first server 20 and a second server 30. The first server 20 and the second server 30 establish an information transmission relationship via wired and / or wireless means. The first server 20 is used to receive information from any terminal and to encrypt and / or store the information. The first server 20 is also used to respond to deletion requests and / or information retrieval requests issued by any terminal, and to retrieve and / or delete specified information.

[0034] This invention uses personal information as an example to illustrate the system's operation steps. The system of this invention can also encrypt, delete, and recover various types of information.

[0035] Preferably, the first server 20 classifies personal information into different sensitivity levels and generates corresponding encryption keys to encrypt the personal information. Then, it distributes key fragments to other second servers 30. When the personal information subject needs to retrieve the personal information data, the first server 20 recovers the key according to the key fragments and decrypts the personal information data. When the personal information subject needs to delete the personal information data, the first server 20 sends a key deletion instruction to the second server 30.

[0036] The second server 30 is used to split the key corresponding to the encryption key and to delete the key fragments after receiving a deletion instruction from the first server.

[0037] The processing hardware in the first server 20 and the second server 30 of the present invention may be a dedicated integrated chip, CPU, logic processor, etc., and also includes a device capable of reading the code data of the method of the present invention stored in the disk medium and running the method of the present invention.

[0038] The first server 20 and the second server 30 in this invention can also be integrated into a single processor to execute the method of this invention.

[0039] Example 1

[0040] The system of the present invention includes at least a processor. The processor includes a first server and a second server 30.

[0041] The first server is configured as follows:

[0042] Information fields are divided into at least two sensitivity levels based on their degree of sensitivity;

[0043] An encryption key and its key fragments are generated based on a preset threshold, and a mapping between the target and the key fragments is established.

[0044] Encrypt the information fields corresponding to different sensitivity levels using encryption keys of different sensitivity levels and delete the original information data;

[0045] Upon receiving a recovery request, the encryption key is recovered and decrypted based on the key fragments to obtain the original information data.

[0046] Specifically, the first server 20 establishes an information transmission relationship with at least one terminal 10 via wired and / or wireless means. Terminal 10 refers to a device capable of receiving information and engaging in human-computer interaction. Examples of terminals include computers, tablets, smartphones, smartwatches, smart glasses, VR devices, and other devices capable of inputting and transmitting personal information.

[0047] Specifically, S1: The first server 20 receives information sent by at least one terminal 10.

[0048] S2: The first server 20 classifies the specified information into levels according to the data sensitivity level corresponding to the specified information. The specified information is not limited to personal information, and can also be several types of information that need to be kept confidential, such as financial information, trade information, etc.

[0049] For example, information is divided into {L1, L2, …, L m} according to sensitivity levels. L1 is the lowest sensitivity level, and L m is the highest sensitivity level. For information I, the first server 20 divides the fields of information I into m parts {I1, I2, …, I m} according to sensitivity.

[0050] The information is divided according to sensitivity levels, split into fields of different sensitivity levels, and then each sensitivity level field is encrypted and stored with different encryption keys respectively. When a user can access a field of a certain sensitivity level, they can also access all fields with sensitivity levels lower than that level, and vice versa.

[0051] S3: According to the current operating status of the system, the first server 20 selects the key sharding threshold t.

[0052] There are two types of operating status, namely that no server has experienced downtime in a short period of time, and that a server has experienced downtime in a short period of time. If no server has experienced downtime in a short period of time, select the threshold t = n; if a server has experienced downtime in a short period of time, select the threshold t < n.

[0053] The threshold t is a positive integer, and the value range is 1≤t≤n.

[0054] S4: The first server 20 randomly generates encryption keys {K1, K2, …, K m} by adopting different strategies according to the threshold t, and performs key sharding on the encryption keys.

[0055] When the threshold t < n, the selected strategies are steps S41, S42, and S43.

[0056] When the threshold t = n, the selected strategies are steps S44, S45, and S46.

[0057] The first server 20 uses the encryption keys {K1, K2, …, K m} to encrypt the information fields {I1, I2, …, I m} to obtain ciphertext information {C1, C2, …, C m}.

[0058] The first server 20 may also recover the encryption key through at least t encrypted key shards, perform key management in a multi-party collaborative manner, and establish a mapping between targets and key shards. A target refers to an object to be deleted.

[0059] For example, assuming there are n servers in the domain, multi-party collaborative key management of the encryption key is performed through the n servers. A threshold t is set. When t<n, the first server 20 generates n key shards for each key, and the original key can be recovered only by collecting no less than t key shards.

[0060] Root

[0061] The steps for generating an encryption key are:

[0062] According to sensitivity levels {L1, L2, …, L m}, randomly generate encryption keys {K1, K2, …, K m} respectively.

[0063] The random generation algorithm herein includes: determining the key length, generating a random number of corresponding length, and processing the random number to obtain the key.

[0064] The sensitivity level division of user information can be determined according to the impact of the information on personal privacy and the degree of threat to personal safety.

[0065] For example, user information includes fields such as ID number, phone number, address, gender and name. Among them, phone number and gender belong to information of low sensitivity level L1, name belongs to information of medium sensitivity level L2, and ID number and address belong to information of high sensitivity level L3.

[0066] For each encryption key K i (1≤i≤m), the sharding steps include:

[0067] S41: Based on encryption key K i and threshold t, randomly generate t-1 numbers a j (1≤j≤t-1) as coefficients; the numbers a j are natural numbers.

[0068] S42: Take encryption key K i as a constant term to construct a (t-1)-th order polynomial:

[0069] f(x) = a t-1 x t-1 +…+a2x 2 +…+a1x 1 +K i .

[0070] S43: Randomly generate n non-zero numbers xk (1≤k≤n), the nonzero number x k Substituting into the (t-1)th order polynomial, the data (x) is calculated. k ,f(x k )), 1≤k≤n.

[0071] Data (x) k ,f(x k This is used as n key fragments. These fragments will be combined with the encryption key K. i The corresponding n key fragments are denoted as

[0072] When t=n, each encryption key will generate n key fragments, and all n keys need to be collected to recover the original key.

[0073] Preferably, the steps for establishing the target-key fragment mapping are as follows.

[0074] S44: Select n random values ​​and mark the key fragments as key fragments.

[0075] S45: Perform an XOR operation on the n key fragments. The first result obtained is labeled K. m First result K m For L m Sensitivity level encryption keys, key fragmentation To match the first result K m The corresponding key fragments.

[0076] S46: Fragment the key Perform hash operation The second result obtained is labeled as XOR operation on n key fragments Let the third result be denoted as K. m-1 Third result K m-1 For L m-1 Sensitive level encryption keys, To be consistent with the third result K m-1 The corresponding key fragments.

[0077] Each sensitivity level L i The corresponding encryption key fragments are all from the next higher level L. i+1 The encryption key is derived by fragmenting the encryption key, with the lowest sensitivity level L1 corresponding to the encryption key K1. This is the key fragment corresponding to K1.

[0078] When the threshold t < n, each key share is obtained through a large number of algebraic operations, which can recover the original key when t or more key shares are collected. That is to say, the cost of this function is a large amount of complex calculations. When the threshold t = n, all n key shares need to be collected to recover the original key, so hash operation and XOR operation are used to obtain the key shares, which has the advantage of a much higher calculation speed than the previous method.

[0079] S5: the first server 20 deletes the original information data and deletes the encryption key.

[0080] S6: the first server 20 distributes the key shares to the second server 30.

[0081] Distributed storage is performed on keys of each sensitivity level to prevent key leakage caused by the keys being stolen by attackers.

[0082] S51: use the encryption key {K1,K2,…,K m} to encrypt information fields of different sensitivity levels {I1,I2,…,I m} respectively to obtain ciphertext information {C1,C2,…,C m}.

[0083] S52: delete the original information fields {I1,I2,…,I m}, and delete the original information I.

[0084] S53: when t < n, delete the encryption keys of all sensitivity levels {K1,K2,…,K m}, for each encryption key, distribute n key shares corresponding to it to n second servers 30 respectively, at this time, each second server 30 stores m key shares, which correspond to m sensitivity levels respectively.

[0085] When t = n, delete the encryption keys of all sensitivity levels {K1,K2,…,K m}, delete all key shares corresponding to the encryption keys {K1,K2,…,K m-1}, for encryption key K m corresponding key shares distribute the n key shares to n second servers 30 respectively.

[0086] S7: the second server 30 stores the corresponding key shares.

[0087] S8: the terminal 10 issues an extraction request for retrieving personal information of sensitivity level L i , the first server 20 receives the extraction request.

[0088] S9: The first server 20 collects t key shards from no less than t second servers 30, and recovers the corresponding encryption key K i , so as to decrypt and recover the information with sensitivity level L i I i .

[0089] To recover the information with sensitivity level L i , it is necessary to recover the encryption key K corresponding to the sensitivity level i .

[0090] When t < n, collecting t key shards from t second servers is enough to construct a system of linear equations of order t, thereby solving for the encryption key K i , wherein (x i , f(x i )) are all key shards, which are known values in the equations.

[0091]

[0092] For server clusters that are prone to single point of failure, the encryption key is managed in an (n, t) threshold manner: that is, the encryption key is split into n key shards, which are respectively distributed to n servers, and the key can be recovered by collecting t of the key shards. This method can provide certain fault tolerance, and the key can still be recovered normally when a single server has a single point of failure.

[0093] When t = n, it is necessary to collect n key shards from n second servers that is, each current second server 30 stores an encryption key shard corresponding to sensitivity level L w , then all the key shards are respectively subjected to w-i hash operations to obtain the key shard corresponding to the encryption key K i then an XOR operation is performed on these key shards to obtain the encryption key K i , that is

[0094] For server clusters that are not prone to single point of failure, the key is split into n key shards which are respectively distributed to n servers, and all n key shards are required to recover the key. When this key sharding method is adopted, the key can be guaranteed to be unrecoverable only by deleting the key shard on any one server; meanwhile, keys with low sensitivity level can be derived from keys with high sensitivity level, which can reduce the storage space overhead of key shards on servers.

[0095] Use the encryption key K i to decrypt the ciphertext C with the corresponding sensitivity level i ​the personal information field I in plaintext form can be recovered i .

[0096] S10: the first server 20 returns information I to the terminal 10 i .

[0097] S11: the terminal 10 sends a request for deleting information with sensitivity level L i .

[0098] S12: the first server 20 sends a deletion instruction to the second server 30

[0099] S13: the corresponding key shards are deleted from the second server 30, ensuring that the key K j (i≤j≤m) cannot be recovered from the remaining key shards, and only encryption keys {K1,K2…K i-1} can still be recovered via key shards.

[0100] the process of deleting information of a certain sensitivity level at least comprises:

[0101] assuming that information with sensitivity level L i is to be deleted, then the corresponding encryption key K i needs to be deleted, and key shards with higher sensitivity levels than this level are also deleted, so that personal information with higher sensitivity levels than this level cannot be recovered either.

[0102] when t<n, for each encryption key K j (i≤j≤m), at least n-t+1 key shards of K j on servers need to be deleted, ensuring that the key K j cannot be recovered from the remaining key shards, and only encryption keys {K1,K2,…,K i-1} can still be recovered via key shards.

[0103] when t=n, existing encrypted key shards are first subjected to w-i+1 times of hash operations to obtain key shards which are the key shards corresponding to K i-1 ; then one of the key shards is arbitrarily deleted. At this time, the encryption key K cannot be recovered from the remaining key shards, and the encryption keys {K w ,K w-1 …,K w-2} also cannot be derived and recovered from the remaining key shards. The encryption key K can be recovered by using the key shards i , and {K1,K2,…,K } can also be derived from K i-1 i-2 via K i-1 ​The key is fragmented and then derived and recovered.

[0104] Finally, update the key shards stored on each node to...

[0105] Example 2

[0106] This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0107] A method for encrypting and reliably deleting information, characterized in that the method includes at least:

[0108] Preferably, the method further includes: during the process of deleting information of a specified sensitivity level, deleting the key fragment corresponding to the sensitivity level.

[0109] Preferably, the method further includes: during the process of deleting information of a specified sensitivity level, information fields whose own sensitivity level is higher than that of the deleted key fragment are restricted from access.

[0110] Preferably, the method further includes: the step of establishing the mapping between the target and the key fragment is performed based on a multi-party collaborative key management method.

[0111] Preferably, the steps of the multi-party collaborative key management method include at least:

[0112] In a scenario where n servers collaboratively manage an encryption key, the encryption key generates n key fragments based on a set threshold t; at least t of the key fragments are collected to recover the original key; the encryption key is randomly generated based on a preset sensitivity level; and the encryption key is fragmented to generate the key fragments.

[0113] Preferably, the step of fragmenting the encryption key includes at least: randomly generating t-1 coefficients a based on the threshold t. j Construct a polynomial of order t-1, f(x) = a t-1 x t-1 +…+a2x 2 +…+a1x 1 +K i Among them, K i Represents the encryption key, a t-1 Represents coefficient a j x represents a variable; n non-zero numbers x will be randomly generated. k Substituting into the t-1 polynomial, we can calculate (x) k ,f(x kas n key shards, wherein 1≤k≤n; when t=n, each key generates n shards, and the original key is recovered by collecting all n shards.

[0114] Preferably, the step of recovering the encryption key based on the key shards at least comprises: selecting n random values, and marking the key shards as performing an XOR operation on the key shards the first calculation result K m is an encryption key of sensitivity level L m , and it is a key shard corresponding to the first result K m ; performing a hash operation on the key shards marking the obtained second result as performing an XOR operation on n key shards recording the obtained third result as K m-1 . The third result K m-1 is an encryption key of sensitivity level L m-1 , and it is a key shard corresponding to the third result K m-1 . The n key shards are respectively distributed to n servers.

[0115] the process of recovering personal information of a certain sensitivity level at least comprises:

[0116] assuming that personal information of sensitivity level L i is to be recovered, the corresponding encryption key K i needs to be recovered.

[0117] when t<n, it is necessary to collect t key shards from t servers, so that a t-order system of linear equations can be constructed to solve the encryption key K i

[0118]

[0119] when t=n, it is necessary to collect n key shards from n servers that is, each server currently stores an encryption key shard of sensitivity level L w , then performing w-i hash operations on all key shards respectively to obtain a key shard corresponding to the encryption key K i then performing an XOR operation on these key shards to obtain the encryption key K i , that is,

[0120] ​​​Using the encryption key K i to decrypt the ciphertext C with the corresponding sensitivity level i to restore the plaintext personal information field I i .

[0121] The process of deleting personal information of a certain sensitivity level at least comprises:

[0122] Assuming that the personal information of sensitivity level L i is to be deleted, it is necessary to delete the corresponding encryption key K i , and delete key shards with sensitivity levels higher than this level, so that personal information with sensitivity levels higher than this level cannot be restored either;

[0123] When t<n, for each encryption key K j (i≤j≤m), it is necessary to delete K on at least n-t+1 servers j key shards to ensure that the encryption key K j cannot be restored from the remaining key shards. At this time, only the encryption key {K1,K2,…,K i-1} can still be restored through key shards;

[0124] When t=n, first perform w-i+1 hash operations on the existing encryption key shards to obtain key shards which are the key shards corresponding to K i-1 ; then randomly delete one of the key shards . At this time, the encryption key K w cannot be restored from the remaining key shards, and the encryption key {K w-1 , K w-2 …, K i} also cannot be derived and restored from the remaining key shards. Whereas the encryption key K can be restored from the key shards , the encryption key K i-1 , {K1,K2,…,K i-2} can also be derived and restored from the key shards of K i-1 . Finally, update the key shards stored by each node to

[0125] It should be noted that the specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and not intended to limit the scope of the claims. The scope of protection of this invention is defined by the claims and their equivalents. This specification contains multiple inventive concepts; terms such as "preferredly," "according to a preferred embodiment," or "optionally" indicate that the corresponding paragraph discloses an independent concept. The applicant reserves the right to file divisional applications based on each inventive concept.

Claims

1. A method for encrypting and reliably deleting information, characterized in that, The method includes at least: Information fields are divided into at least two sensitivity levels based on their degree of sensitivity; An encryption key and its key fragments are generated based on a preset threshold, and a mapping between the target and the key fragments is established. Encrypt the information fields corresponding to different sensitivity levels using encryption keys of different sensitivity levels and delete the original information data; Upon receiving a recovery request, the encryption key is recovered and decrypted based on the key fragments to obtain the original information data; The process of deleting information of a certain sensitivity level includes: Assume that the system's various sensitivity levels, from low to high, correspond to the encryption keys in ascending order. to Wherein, the sensitivity level of the information to be deleted is 1. With the aforementioned sensitivity level Corresponding encryption key The current system's highest sensitivity level is The sensitivity level corresponding to the currently existing encryption keys is: ; Set the threshold value as follows There are n servers in the domain, and the value range is 1≤t≤n; when At that time, for each encryption key All of them need to be deleted at least Encryption keys on each server Key fragmentation ensures the encryption key is secure. It is impossible to recover from the remaining key fragments; at this point, only the encryption key is available. Recovery is still achieved through key fragmentation; when At that time, the existing encryption key is first fragmented. conduct The hash operation yields key fragments. That is, with the encryption key The corresponding key fragments; then arbitrarily delete the key fragments. One of them; at this time, the encryption key The encryption key cannot be recovered from the remaining key fragments. It is also impossible to derive and recover from the remaining key fragments; using key fragmentation Recover the encryption key , From the encryption key The key is fragmented and then derived and recovered.

2. The information encryption and trusted deletion method according to claim 1, characterized in that, The method further includes: During the process of deleting information of a specified sensitivity level, the key fragment corresponding to the sensitivity level is deleted.

3. The information encryption and trusted deletion method according to claim 1, characterized in that, The method further includes: During the deletion of information with a specified sensitivity level, information fields with a sensitivity level higher than that of the deleted key fragment are restricted from access.

4. The information encryption and trusted deletion method according to claim 1, characterized in that, The method further includes: the step of establishing the mapping between the target and the key fragment is carried out based on a multi-party collaborative key management method.

5. The information encryption and trusted deletion method according to claim 4, characterized in that, The steps of the multi-party collaborative key management method include at least: exist In the case where multiple servers collaborate on key management for encryption keys, the encryption keys are based on a set threshold. generate Each of the aforementioned key fragments; Collect no less than the threshold The original key is recovered by fragmenting the key. The encryption key is randomly generated based on a preset sensitivity level; The encryption key is fragmented to generate the key fragments.

6. The information encryption and trusted deletion method according to claim 5, characterized in that, The steps of fragmenting the encryption key include at least the following: Based on the threshold Randomly generated coefficients ; structure polynomial of order ; in, This represents the encryption key. Represents coefficients ; Represents variables; Will be randomly generated nonzero numbers Substitution In the polynomial, the calculated As Each key fragment ; when At that time, each key will generate Each segment collects all. The original key was recovered from each fragment.

7. The information encryption and trusted deletion method according to claim 1, characterized in that, The steps for recovering the encryption key based on the key fragments include at least the following: choose A random value is used to mark the key fragment. ; Perform an XOR operation on the key fragments The first result obtained from the calculation for Sensitive level encryption keys, To match the first result Corresponding key fragmentation; Key fragmentation Perform hash operation The second result obtained is marked as ; right Each key fragment is XORed. The third result is denoted as ; Third Result for Sensitive level encryption keys, To the third result The corresponding key fragments.

8. An information encryption and trusted deletion system, characterized in that, It includes at least a processor, which is configured to: Information fields are divided into at least two sensitivity levels based on their degree of sensitivity; An encryption key and its key fragments are generated based on a preset threshold, and a mapping between the target and the key fragments is established. Encrypt the information fields corresponding to different sensitivity levels using encryption keys of different sensitivity levels and delete the original information data; Upon receiving a recovery request, the encryption key is recovered and decrypted based on the key fragments to obtain the original information data; The process of deleting information of a certain sensitivity level includes: Assume that the system's various sensitivity levels, from low to high, correspond to the encryption keys in ascending order. to Wherein, the sensitivity level of the information to be deleted is 1. With the aforementioned sensitivity level Corresponding encryption key The current system's highest sensitivity level is The sensitivity level corresponding to the currently existing encryption keys is: ; Set the threshold value as follows There are n servers in the domain, and the value range is 1≤t≤n; when At that time, for each encryption key All of them need to be deleted at least Encryption keys on each server Key fragmentation ensures the encryption key is secure. It is impossible to recover from the remaining key fragments; at this point, only the encryption key is available. Recovery is still achieved through key fragmentation; when At that time, the existing encryption key is first fragmented. conduct The hash operation yields key fragments. That is, with the encryption key The corresponding key fragments; then arbitrarily delete the key fragments. One of them; at this time, the encryption key The encryption key cannot be recovered from the remaining key fragments. It is also impossible to derive and recover from the remaining key fragments; using key fragmentation Recover the encryption key , From the encryption key The key is fragmented and then derived and recovered.

9. The information encryption and trusted deletion system according to claim 8, characterized in that, The processor is also configured to: During the process of deleting information of a specified sensitivity level, the key fragment corresponding to the sensitivity level is deleted.

10. The information encryption and trusted deletion system according to claim 8 or 9, characterized in that, The processor is also configured to: During the deletion of information with a specified sensitivity level, information fields with a sensitivity level higher than that of the deleted key fragment are restricted from access.

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