Combined public key CPK(CombinedPublicKey) digital signature protocol and ID-based key exchange protocol satisfy the scale of proof and the directness of verification, truly realize Shamir's idea and open up a new way to solve the scale by combination.
In 2007, on the basis of combined public key, a two-factor compound combined public key TF-CPK was formed, which retained the advantages of combined public key, enhanced security, realized compound digital signature and key exchange mechanism respectively, and solved the difficulty of individual defining signature key under centralized management mode.
principle
CPK key management system is an identity-based key generation and management system based on discrete logarithm problem.
According to the mathematical principle of discrete logarithm problem, it constructs a public key and a private key matrix, and uses hash function and cryptographic transformation to map the entity's identity into the row coordinate and column coordinate sequence of the matrix, so as to select and combine the matrix elements, and generate a large number of public key and private key pairs composed of public key and private key, thus realizing identity-based super-large-scale key generation and distribution.
Key production and management in CPK key management system are centralized. It accepts applications from entities through registration department (RA), production department (PA) and distribution department (DA), checks identities, generates private keys according to identities, and distributes them to entities statically.
The private key of each entity is stored in a decentralized way, and the public key matrix can be stored in the most accessible way for any entity to call conveniently, so that any entity can generate its own public key according to the identification of the other party. ?
CPK key management system also uses the method of defining range key parameters to realize the division of different systems. The setting of multiple logos of an entity meets the requirements of multiple functions of one card, making the system safer, more flexible and more adaptable in application.
The CPK key management system can be constructed based on the general discrete logarithm problem of finite field or elliptic curve. In view of the fact that the elliptic curve discrete logarithm problem has the advantage of occupying less resources than the general finite field discrete logarithm problem under the same safety degree.
The above contents refer to:
Baidu encyclopedia -CPK