Dynamic Group Digital Signature Based on Fractal Sets According to Text Content

Group digital signature lets each member of a group sign a message on behalf of the entire group, in a way that the identity of signers is not revealed. In this paper, a new method for group digital signature based on Mandelbrot and Julia fractal sets according to Text Content is presented. In this method, the concept of documents text content is used in order to categorize the members whose identity is confirmed for each text. This scheme may be used for signing sensitive documents. Texts and documents can be categorized into classified, secret, and top-secret according to their sensitivity. The group manager selects qualified authorized people to sign documents according to text type. In this method, group members are placed on the leaves of a binary tree structure and sign texts while interacting with each other. The presented method resists coalition attacks and enjoys larger key space compared to RSA and DSA algorithms. The public key size in the presented method is independent of the number of group members. Moreover, group departure protocol is also incorporated in this method and the method is thus completely dynamic. The members’ position in the tree structure is vague in this scheme. This helps to increase security. The fractal dynamic group digital signature presented can be an appropriate substitute for current group digital signature schemes.