Legal basis: People's Republic of China (PRC) Patent Law.
Article 4 Where an invention-creation applying for a patent involves national security or vital interests and needs to be kept confidential, it shall be handled in accordance with the relevant provisions of the state.
Article 18 Foreigners, foreign enterprises or other foreign organizations that have no habitual residence or business office in China who apply for patents and handle other patent affairs in China shall entrust a legally established patent agency to handle them. Units or individuals applying for patents and handling other patent affairs in China may entrust a legally established patent agency to handle them. Patent agencies shall abide by laws and administrative regulations, accept the entrustment of clients, and handle patent applications or other patent affairs; The contents of the client's invention and creation shall be kept confidential, except that the patent application has been published or announced. Specific measures for the administration of patent agencies shall be formulated by the State Council.