Dynamic password system of visual secret sharing

The present invnetion discloses a dynamic password system of visual secret sharing, which comprises a private secret shadow generation module, a public shadow generation module, an optical character recognition module and a private secret shadow updating module. The system generates private secret shadow first for every user, one copy of which is stored in the database of the server, one copy is stored in the diskette for users to keep. Before entering the system, users need to put the IC card which stores the private secret shadow into the IC card reader, and then input user's account number which will be transmitted to the server through the network. The server will check if the user account is legal after the user's account number is received. If the user's account is legal, the mapped private shadow will be found from the database, and then the server will generate a password randomly, and generate a public shadow based on the user's private shadow and password to be transmitted to the client, the client program can combine the public shadow and private shadow to generate the pass shadow, and then optical character recognition technology is used to convert the password image displayed by the pass shadow into character code to replace manual input. The password is then transmitted from the client to the server, the server will check if the password is correct, if it is, users are allowed to enter the system and transmit back the updating way of the private shadow, user's private shadow is updated at client site, otherwise the user will be rejected to enter the system.