Applying to no / weak local storage system client digital certificates system belong to a digital certificate system technology. Its features are: based on public key infrastructure architecture, containing certificates body system, a registered body system, certificate management systems, key management system, information dissemination and interface systems and procedures for client visit one or more of these components, adopted random number, salt and several rounds of iteration, etc to guarantee the security of the system and conducted by the client decryption key generation and processing operation means to achieve the system's scalability. The system without the help of key external storage devices solved the network computer systems deployed digital certificate system in the terminal when the entity's private key data storage needs of the local computer network and storage characteristics of contradictions. Thus in ensuring security and scalability simultaneity, the digital certificate system implementation complexity and costs are lower.