Evidence storage method and system based on SM2 blind signature
By using an evidence preservation method based on SM2 blind signatures, the problem of hiding evidence details during the evidence preservation process is solved, and the effect of preventing tampering and leakage before public disclosure is achieved, thus ensuring the security and privacy protection of evidence.
Patent Information
- Application Number
- CN202511151619.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-18
- Publication Date
- 2025-11-18
AI Technical Summary
During the evidence preservation process, existing technologies struggle to effectively conceal evidence details in terms of data integrity and privacy protection, preventing evidence from being tampered with or leaked before it is made public.
An evidence preservation method based on SM2 blind signature is adopted. The evidence is sent to the server for blind signing after being blinded, and deblinding is performed when needed to ensure that the evidence is not tampered with or leaked before being made public. The domestic SM2 algorithm is used for signature verification.
It enables the concealment of evidence details before public disclosure, preventing tampering and leakage, while ensuring the security and privacy of the evidence. The SM2 algorithm is used to verify the validity of the signature, ensuring the integrity and anonymity of the evidence.
Smart Images
Figure CN120979673A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the field of cryptography, and particularly relates to an evidence storage method and system based on SM2 blind signature. BACKGROUND
[0002] With the development of digital technology, evidence storage is gradually changing from traditional methods to electronic storage. In order to ensure the validity and credibility of the evidence, there are many security requirements in terms of data integrity, privacy protection and the like. When the user end submits the evidence to the service end, it is desired to hide the evidence details before the evidence is disclosed, so as to prevent the evidence from being tampered with or leaked.
[0003] Blind signature is a special cryptographic signature technology, and its core feature is that the signer signs the information without knowing the specific content of the signature. The user can send the information to be signed to the signer after "blinding" processing, and the signer completes the signature, and then the user "unblinds" the signature, and finally obtains the effective signature of the original information. When the user end submits the evidence to the service end, the evidence details are hidden through blind signature, so as to prevent the evidence from being tampered with or leaked before being disclosed. SUMMARY
[0004] The main problem solved by the present application is how to blind sign the evidence, and an evidence storage method and system based on SM2 blind signature are provided.
[0005] To solve the above technical problems, the technical scheme adopted is: An evidence storage method based on SM2 blind signature, comprising the following steps: Step 1: the service end generates a signature private key d, and calculates a public key P=[d]G according to the private key d, and publicly discloses the public key P; Step 2: the user end blinds the evidence M; Step 3: the user end respectively performs signature preprocessing based on the SM2 algorithm on the evidence M and the blinded blind evidence , to obtain an original evidence message digest e and a blinded evidence message digest ; Step 4: the user end calculates a blinding factor , which is a parameter participating in the blind signature, and n is the order on the elliptic curve E based on the SM2 algorithm; Step 5: the user end takes the blinding factor u as a user end private key based on the SM2 algorithm, and calculates a user end public key V=[u]G through the blinding factor u; Step 6: the user end public key V and the blinded evidence are submitted to the service end; Step 7: the service end signs the blinded evidence performing blind signature; Step 8: When the evidence needs to be disclosed, the user end deblinds the blind signature according to the blinding factor to obtain the signature of the original evidence by the service end; Step 9: Verify the validity of the signature of the original evidence by the service end using the public key P of the service end, and if there is no error, disclose the original evidence.
[0006] Further, the blinding of the evidence by the user end means that the user end hides the sensitive information in the evidence, so that the blinded evidence is different from the original evidence.
[0007] Further, the method for the service end to perform blind signature on the blinded evidence is: Step 3.1: The service end performs signature preprocessing on the blinded evidence to obtain the message digest of the judicial blinded evidence ; Step 3.2: The service end generates random numbers using a random number generator, calculates elliptic curve points based on the SM2 algorithm according to the random numbers k1 and k2, records the coordinates of W as (x1, y1), and calculates the signature value according to x1 and the message digest of the judicial blinded evidence , if , then repeat this step; Step 3.3: The service end calculates the signature value according to the private key d, wherein represents data splicing, wherein , , wherein represents the inverse element of n in the finite field Fq, and is recorded as the blind signature result.
[0008] Further, when the evidence needs to be disclosed, the user end deblinds the blind signature result using the blinding factor u.
[0009] Further, the method for the user end to deblind the blind signature result is: Step 8.1: According to the blind signature result , perform de-splicing on to obtain x and y; Step 8.2: According to the values of x and y, calculate , using the blinding factor u to obtain the signature value (r, s).
[0010] Further, the method for verifying the validity of the signature of the original evidence by the service end using the public key p of the service end is: Step 9.1: the process of verifying the signature based on the SM2 algorithm, the signature pre-processing is performed on the published evidence M to obtain a message digest e; Step 9.2: calculating the signature value (r, s) according to the signature value (r, s) If t = 0, the verification fails. Step 9.3: calculating the elliptic curve point , the coordinates of U are , calculating If R = r is true, the verification passes, otherwise the verification fails, P represents the public key published by the service end, G is the base point of the n-order on the elliptic curve E.
[0011] The present application also provides an evidence storage system based on SM2 blind signature, which uses an evidence storage method based on SM2 blind signature to realize each step.
[0012] By adopting the above technical scheme, the present application has the following beneficial effects: The evidence storage method and system based on SM2 blind signature provided by the present application hide the evidence details through blind signature by blinding the evidence and sending the blinded evidence to the service end for blind signature, prevent the evidence from being tampered with or leaked before being published, and when the original evidence is published, the user end removes the blind signature result to obtain the signature of the original evidence, and then verifies the validity of the signature of the original evidence based on the SM2 algorithm. If the validity verification passes, it indicates that the original evidence has not been tampered with, and at the same time, it is ensured that the original evidence is in the hands of the user end before being published. BRIEF DESCRIPTION OF DRAWINGS
[0013] Figure 1 The system flowchart of the present application. DETAILED DESCRIPTION
[0014] The technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0015] Figure 1 A kind of evidence storage method based on SM2 blind signature of the present application is shown, including the following steps: Step 1: the service end generates a signature private key d, and calculates a public key P = [d] G according to the private key d, and publishes the public key P.
[0016] Step 2: the user end blurs the evidence M.
[0017] In this embodiment, the user end blinding the evidence means that the user end hides the sensitive information in the evidence, so that the blinded evidence is different from the original evidence. The way to hide the sensitive information can be to delete the evidence detail description, to obtain the blinded evidence by blackening, desensitizing, encrypting, etc. .
[0018] Step 3: The user end respectively performs SM2 algorithm-based signature preprocessing on the evidence M and the blinded evidence , to obtain the original evidence message digest e and the blinded evidence message digest .
[0019] In this embodiment, the method of signature preprocessing is according to Chapter 6 “Generation Algorithm and Process of Digital Signature” in GB / T 32918.2-2016 “Information Security Technology SM2 Elliptic Curve Public Key Cryptography Part 2: Digital Signature Algorithm”. When signing, the pre-processing of the data to be signed is required according to the requirements of GB / T 35276-2017 “Information Security Technology SM2 Cryptographic Algorithm Usage Specification”.
[0020] Step 4: The user end calculates the blinding factor , which is a parameter participating in the blinded signature. n is the order on the elliptic curve E based on the SM2 algorithm. According to the avalanche effect of the hash algorithm, it is difficult to infer the signature preprocessing e on M from the signature preprocessing result on the blinded evidence . In this embodiment, the is used as the blinding factor.
[0021] Step 5: The user end calculates the user end public key V=[u]G by taking the blinding factor u as the user end private key based on the SM2 algorithm.
[0022] In this embodiment, when the user end sends the blinding factor to the service end, in order to prevent the blinding factor from being leaked, the blinding factor is processed into a public key using the SM2 algorithm and then sent.
[0023] Step 6: The user end public key V and the blinded evidence are submitted to the service end.
[0024] Since the user end public key and the blinded evidence are sent to the service end, it is ensured that the original evidence is not disclosed, the original evidence is effectively protected, and the security of the blinding factor and the original evidence is ensured.
[0025] Step 7: The service end performs blind signature on the blinded evidence .
[0026] Blind signature provides key technical support for privacy protection in the digital age through the characteristic of "signature content hiding", especially indispensable in the scene where "anonymity + credibility" coexist. The scheme uses domestic SM2 algorithm to design evidence storage blind signature scheme, which is an innovative application in the field of evidence storage, which ensures that the evidence is truly public before solidifying the evidence and protecting privacy.
[0027] In this embodiment, the method of the server for blind signature of the blinded evidence is: Step 3.1: The server signs the blinded evidence Preprocessing to get the message digest of the judicial blinded evidence .
[0028] In this embodiment, the server is to sign the blinded evidence Preprocessing makes the original evidence invisible to the server, preventing evidence from being tampered with, but ensures that the evidence is submitted to the judicial authority and the evidence is saved.
[0029] Step 3.2: The server generates a random number , calculates the elliptic curve point based on the random numbers k1 and k2 based on the SM2 algorithm, and records the coordinates of W as (x1, y1). According to x1 and the message digest of the judicial blinded evidence Calculate the signature value If , repeat this step; Step 3.3: The server calculates the signature value According to the private key d, wherein Represents data splicing, wherein , , wherein Represents The inverse element of n in the finite field Fq, denoted as Blind signature result.
[0030] In this embodiment, the material signed in the process of blind signature is the blinded evidence material, which ensures the confidentiality of the evidence to the judicial authority.
[0031] Step 8: When the evidence needs to be disclosed, the user end deblinds the blind signature according to the blinding factor to get the signature of the original evidence by the server.
[0032] In this embodiment, when the evidence needs to be disclosed, the user end uses the blinding factor u to deblind the blind signature result The method of the user end for deblinding the blind signature result is: Step 8.1: According to the blind signature result , De-splicing is performed to obtain x and y; Step 8.2: According to the x and y values, the blind factor u is used to calculate , The signature value (r, s) is obtained.
[0033] In this embodiment, the evidence is blinded by using a blind factor, then the blinded evidence is blindly signed, and then when the evidence needs to be disclosed, the blind signature is de-blinded by using the blind factor to obtain the signature of the original evidence by the server, that is, the judicial organ. Then, by verifying the validity of the signature, it can be confirmed whether it is a legal signature. If the signature verification is passed, it indicates that the current original evidence is consistent with the original evidence retained by the user end when the blind signature is implemented, and the original evidence can be disclosed. Compared with the general SM2 signature, which must be pre-processed for the original evidence, the blind signature is pre-processed for the blinded evidence when the signature is implemented. Obviously, the blind signature can better protect the privacy in the original evidence.
[0034] Step 9: The signature validity of the original evidence by the server is verified by using the server public key P. If there is no error, the original evidence is disclosed.
[0035] In this embodiment, the method for verifying the signature validity of the original evidence by the server by using the server public key P is to verify by using the SM2-based signature verification method, which is specifically: Step 9.1: The process of verifying the signature based on the SM2 algorithm is pre-processed for the disclosed evidence M to obtain the message digest e. Step 9.2: According to the signature value (r, s), calculate If t = 0, the verification fails. Step 9.3: Calculate the elliptic curve point , the coordinates of U are , calculate If R = r is true, the verification is passed, otherwise the verification fails, P represents the public key disclosed by the server to the outside, , and G is the base point of the n-order elliptic curve E.
[0036] The signature verification method in this embodiment uses the SM2 algorithm verification method to verify the signature.
[0037] The blind signature in the embodiment is a special cryptographic signature technology, and a signer signs information without knowing the specific content of the signature. A user can send the information to be signed to the signer after performing "blinding" processing on the information, the signer completes the signature, and then the user performs "deblinding" on the signature, and finally obtains the effective signature on the original information. Therefore, when the witness submits the evidence to the judicial organ, the details of the evidence are hidden by the blind signature to prevent the evidence from being tampered with or leaked before being disclosed.
[0038] The application also provides an evidence storage system based on the SM2 blind signature, and each step is realized by using an evidence storage method based on the SM2 blind signature.
[0039] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.
Claims
1. A method for evidence preservation based on SM2 blind signatures, characterized in that, Includes the following steps: Step 1: The server generates a private key d for signing, calculates the public key P=[d]G based on the private key d, and then publishes the public key P. Step 2: The user blinds evidence M; Step 3: The user terminal processes evidence M and the blinded evidence separately. Perform signature preprocessing based on the SM2 algorithm to obtain the original evidence message digest e and the blinded evidence message digest. ; Step 4: Calculate the blinding factor on the user end. The blinding factor refers to the parameter involved in the blinding signature, where n is the order on the elliptic curve E based on the SM2 algorithm; Step 5: The user terminal uses the blinding factor u as the user terminal private key based on the SM2 algorithm, and calculates the user terminal public key V=[u]G through the blinding factor u; Step 6: Connect the user-end public key V and the blinded evidence Submit to the server; Step 7: Server-side processing of blinded evidence Perform blind signature; Step 8: When it is necessary to disclose evidence, the user client deblinds the blind signature according to the blinding factor to obtain the server's signature of the original evidence; Step 9: Use the server's public key P to verify the validity of the server's signature on the original evidence. If there is no error, then publish the original evidence.
2. The evidence preservation method based on SM2 blind signature according to claim 1, characterized in that, Blinding evidence on the user end refers to hiding sensitive information in the evidence on the user end, making the blinded evidence different from the original evidence.
3. The evidence preservation method based on SM2 blind signature according to claim 1, characterized in that, The server-side method for blind signing of blinded evidence is as follows: Step 3.1: Server-side processing of blinded evidence Signature preprocessing is performed to obtain a message digest of judicially blinded evidence. ; Step 3.2: The server generates random numbers using a random number generator. Elliptic curve points are calculated based on random numbers k1 and k2 using the SM2 algorithm. Let the coordinates of W be (x1, y1), based on x1 and the message digest of evidence used for judicial blinding... Calculate signature value ,like If the value is 0, repeat this step. Step 3.3: The server calculates the signature value based on the private key d. ,in This indicates data concatenation, where , ,in express The inverse element modulo n over the finite field Fq is denoted by . This is the result of a blind signature.
4. The evidence preservation method based on SM2 blind signature according to claim 1, characterized in that, When evidence needs to be made public, the user client uses a blinding factor u to blind the signature result. To eliminate blindness.
5. The evidence preservation method based on SM2 blind signature according to claim 2, characterized in that, The method for deblinding blind signature results on the user side is as follows: Step 8.1: Based on the blind signature result ,right Deconcatenate the data to obtain x and y; Step 8.2: Calculate the blinding factor u based on the x and y values. , Obtain the signature value (r, s).
6. The evidence preservation method based on SM2 blind signature according to claim 5, characterized in that, The method for verifying the validity of the server's signature on the original evidence using the server's public key P is as follows: Step 9.1: The process of verifying the signature based on the SM2 algorithm involves preprocessing the publicly available evidence M to obtain the message digest e; Step 9.2: Calculate based on signature value (r,s) If t=0, the verification fails. Step 9.3: Calculate the points on the elliptic curve Let the coordinates of U be... ,calculate If R=r is true, the verification passes; otherwise, the verification fails. P represents the public key that the server exposes to the outside world. G is the nth-order base point on the elliptic curve E.
7. An evidence storage system based on SM2 blind signatures, characterized in that, The steps of the evidence preservation method based on SM2 blind signature as described in any one of claims 1 to 6.