The signature password purchased by Yangzhou government is a dynamic password selected by the mobile phone registered with the user's business license. According to the requirements of People's Republic of China (PRC) Electronic Signature Law, Regulations on the Administration of Commercial Passwords, Technical Specifications for Passwords and Related Security of Certificate Authentication System, Measures for the Administration of Electronic Authentication Services and Measures for the Administration of Electronic Authentication Services, the signature password is the dynamic password selected by the mobile phone registered with the business license of the legal person.