US-20260128910-A1 - DISTRIBUTED DIGITAL CERTIFICATE IMPLEMENTATION METHODS, COMPUTER DEVICES, AND STORAGE MEDIA

US20260128910A1US 20260128910 A1US20260128910 A1US 20260128910A1US-20260128910-A1

Abstract

A distributed digital certificate implementation is described. Each of n participants generates a respective threshold private key share based on a distributed key generation protocol. Each of at least t+1 of the n participants generates a random value based on an offline-phase protocol. Each of the at least t+1 participants receives a certificate application, and generates a certificate share by signing application information in the certificate application based on an online-phase protocol, the threshold private key share, and the random value generated based on the offline-phase protocol. Any party aggregates at least t+1 signature shares into a total certificate after obtaining the at least t+1 certificate shares.

Inventors

Guofeng TANG
Li Lin
Xin Wang
Yao Wang
Ying Yan

Assignees

Ant Blockchain Technology (shanghai) Co., Ltd.

Dates

Publication Date: 20260507
Application Date: 20251231
Priority Date: 20230831

Claims (17)

1 . A computer-implemented method for distributed digital certificate implementation, comprising: generating, by each of n participants, a respective threshold private key share based on a distributed key generation protocol; generating, by each of at least t+1 of the n participants, a random value based on an offline-phase protocol; receiving, by each of the at least t+1 participants, a certificate application; generating, as a generated signature share, a certificate share by signing application information in the certificate application based on an online-phase protocol, the respective threshold private key share, and the random value generated based on the offline-phase protocol; and aggregating, by any party, at least t+1 signature shares into a total certificate after obtaining the at least t+1 certificate shares.
2 . The computer-implemented method of claim 1 , wherein each of the n participants serves as a node on a blockchain.
3 . The computer-implemented method of claim 1 , comprising: recording the generated signature share in a blockchain ledger.
4 . The computer-implemented method of claim 1 , wherein the n participants further generate a total public key based on the distributed key generation protocol, and any party verifies correctness of a total certificate based on the total public key after obtaining the total certificate and the total public key.
5 . The computer-implemented method of claim 4 , wherein the total public key is stored in a blockchain ledger.
6 . The computer-implemented method of claim 4 , wherein the total certificate is stored in a blockchain ledger.
7 . The computer-implemented method of claim 1 , wherein a distributed key generation phase, an offline phase, and an online phase comprise: in the distributed key generation phase, each of the n participants generates a respective private key share based on the distributed key generation protocol, generates a homomorphic encryption public-private key pair, and sends a homomorphic encryption public key to another participant; in an offline phase of a distributed signature, each of the at least t+1 participants generates a first random value and a second random value of the participant, further obtains a coordinate component based on a homomorphic encryption algorithm of the homomorphic encryption public-private key pair, the offline-phase protocol, and the second random value, and obtains a private key share component mask value based on a respective private key share; and in an online phase of the distributed signature, each of the at least t+1 participants receives the certificate application, and obtains the certificate share by signing the application information in the certificate application based on the first random value of the participant, the private key share component mask value, and the coordinate component.
8 . The computer-implemented method of claim 7 , wherein a distributed key generation phase, an offline phase, and an online phase comprise: in the distributed key generation phase, each of the n participants generates a first random value and a second random value, and exchanges the first random value and the second random value with another participant after homomorphic encryption; and each participant generates a private key share based on the first random value, the second random value, and a sum of secret shares generated based on the distributed key generation protocol that are collected; in an offline phase of a distributed signature, each of the at least t+1 participants updates the private key share of the participant, and generates and broadcasts a third random value of the participant and a corresponding third random value public key; and in an online phase of the distributed signature, each of the at least t+1 participants receives the certificate application, calculates total coordinates of the corresponding third random value public key after collecting the corresponding third random value public key, calculates r in a signature share for a message based on the total coordinates, and further calculates a component s i of the signature share for the application information in the certificate application based on r, the third random value of the participant, and an updated private key share of the participant, to obtain the certificate share.
9 . A non-transitory, computer-readable medium storing one or more instructions executable by a computer system to perform one or more operations for distributed digital certificate implementation, comprising: generating, by each of n participants, a respective threshold private key share based on a distributed key generation protocol; generating, by each of at least t+1 of the n participants, a random value based on an offline-phase protocol; receiving, by each of the at least t+1 participants, a certificate application; generating, as a generated signature share, a certificate share by signing application information in the certificate application based on an online-phase protocol, the respective threshold private key share, and the random value generated based on the offline-phase protocol; and aggregating, by any party, at least t+1 signature shares into a total certificate after obtaining the at least t+1 certificate shares.
10 . The non-transitory, computer-readable medium of claim 9 , wherein each of the n participants serves as a node on a blockchain.
11 . The non-transitory, computer-readable medium of claim 9 , comprising: recording the generated signature share in a blockchain ledger.
12 . The non-transitory, computer-readable medium of claim 9 , wherein the n participants further generate a total public key based on the distributed key generation protocol, and any party verifies correctness of a total certificate based on the total public key after obtaining the total certificate and the total public key.
13 . The non-transitory, computer-readable medium of claim 12 , wherein the total public key is stored in a blockchain ledger.
14 . The non-transitory, computer-readable medium of claim 12 , wherein the total certificate is stored in a blockchain ledger.
15 . The non-transitory, computer-readable medium of claim 9 , wherein a distributed key generation phase, an offline phase, and an online phase comprise: in the distributed key generation phase, each of the n participants generates a respective private key share based on the distributed key generation protocol, generates a homomorphic encryption public-private key pair, and sends a homomorphic encryption public key to another participant; in an offline phase of a distributed signature, each of the at least t+1 participants generates a first random value and a second random value of the participant, further obtains a coordinate component based on a homomorphic encryption algorithm of the homomorphic encryption public-private key pair, the offline-phase protocol, and the second random value, and obtains a private key share component mask value based on a respective private key share; and in an online phase of the distributed signature, each of the at least t+1 participants receives the certificate application, and obtains the certificate share by signing the application information in the certificate application based on the first random value of the participant, the private key share component mask value, and the coordinate component.
16 . The non-transitory, computer-readable medium of claim 9 , wherein a distributed key generation phase, an offline phase, and an online phase comprise: in the distributed key generation phase, each of the n participants generates a first random value and a second random value, and exchanges the first random value and the second random value with another participant after homomorphic encryption; and each participant generates a private key share based on the first random value, the second random value, and a sum of secret shares generated based on the distributed key generation protocol that are collected; in an offline phase of a distributed signature, each of the at least t+1 participants updates the private key share of the participant, and generates and broadcasts a third random value of the participant and a corresponding third random value public key; and in an online phase of the distributed signature, each of the at least t+1 participants receives the certificate application, calculates total coordinates of the corresponding third random value public key after collecting the corresponding third random value public key, calculates r in a signature share for a message based on the total coordinates, and further calculates a component s i of the signature share for the application information in the certificate application based on r, the third random value of the participant, and an updated private key share of the participant, to obtain the certificate share.
17 . A computer-implemented system for distributed digital certificate implementation, comprising: one or more computers; and one or more computer memory devices interoperably coupled with the one or more computers and having tangible, non-transitory, machine-readable media storing one or more instructions that, when executed by the one or more computers, perform one or more operations, comprising: generating, by each of n participants, a respective threshold private key share based on a distributed key generation protocol; generating, by each of at least t+1 of the n participants, a random value based on an offline-phase protocol; receiving, by each of the at least t+1 participants, a certificate application; generating, as a generated signature share, a certificate share by signing application information in the certificate application based on an online-phase protocol, the respective threshold private key share, and the random value generated based on the offline-phase protocol; and aggregating, by any party, at least t+1 signature shares into a total certificate after obtaining the at least t+1 certificate shares.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of PCT Application No. PCT/CN2023/135001, filed on Nov. 29, 2023, which claims priority to Chinese Patent Application No. 202311121706.9, filed on Aug. 31, 2023, and each application is hereby incorporated by reference in its entirety. TECHNICAL FIELD Implementations of this specification pertain to the field of cryptography technologies, and in particular, relate to distributed digital certificate implementation methods, computer devices, and a storage media. BACKGROUND In the early days of the Internet, secure information transmission has become an important problem. To resolve this problem, various encryption algorithms, for example, symmetric encryption algorithms such as a DES, are invented. However, in these encryption algorithms, both parties need to share a key in advance, which is very difficult in an Internet environment. Therefore, a public key encryption technology is invented, which allows both parties to perform secure communication without directly exchanging a key. However, the public key encryption technology introduces a new problem: How to verify authenticity of a public key. To resolve this problem, a digital certificate is invented. A principle of the digital certificate is based on a public key infrastructure (PKI). In the PKI, a third party is widely trusted, and is referred to as a certificate authority (CA). A task of the CA is to authenticate an identity of an entity and issue a digital certificate to the entity. When an entity (for example, a website) needs a digital certificate, the entity generates a pair of public key and private key, and then sends the public key and some identity information to the CA. The CA verifies authenticity of these information, generates a digital certificate including the public key and the identity information of the entity, and signs the certificate by using a private key of the CA. When another entity (for example, a user) needs to verify an identity of the first entity, the another entity can request the digital certificate of the first entity. The user can verify a signature of the certificate by using the public key of the CA, and then encrypt information by using the public key in the certificate, or verify a digital signature of the first entity. It can be seen that a main function of the digital certificate is to verify authenticity of the public key, to ensure secure information transmission. The digital certificate can be used in various network security scenarios, which are as follows: Secure communication: By using the digital certificate, two entities can perform secure communication without directly exchanging a key. For example, to access an HTTPS website, a browser requests a digital certificate of the website, and then encrypts information by using a public key in the certificate. Identity verification: The digital certificate includes identity information of an entity, which can be used to verify an identity of the entity. For example, to download software, a digital signature of the software can be checked, to ensure that the software is released by a trusted company. Data integrity: By using the digital certificate, an entity can generate a digital signature, which can be used to verify data integrity. For example, when an email is received, a digital signature of the email can be checked, to ensure that the email is not tampered with. Therefore, the digital certificate is often compared to an identity card of the user on a network. A public key certificate generally includes identity information of a certificate-holding subject, public key information of the subject, CA information, additional information, and a digital signature added to the above-mentioned information by using a CA private key. The certificate authority plays a vital role in the digital certificate field. The certificate authority is a widely trusted third-party institution, and is responsible for verifying identities of entities (for example, individuals, companies, and websites) and issuing digital certificates to the entities. The following are some of main functions of the certification authority: Identity verification: One of main responsibilities of the CA is to verify an identity of an entity applying for a digital certificate. This typically involves a series of identity verification processes such as verification of company registration information and personal identification information. The CA issues the digital certificates to the entities only after identity verification succeeds. Certificate issuance: The CA issues the digital certificates to the entities once identities of the entities are verified. The certificate includes a public key of the entity and some identity information such as a name of the entity and a validity period of the certificate. All the information is signed by using the private key of the CA, to ensure authenticity and integrity of the certificate. C