Abstract: Based on the characteristics of two dimensional CAD engineering graphics, the complexity of two dimensional CAD engineering graphic was proposed. The definitions of entity complexity, restriction complexity, and characteristic complexity were given, and their calculation methods were presented, respectively. Analysis and discussion illustrate the proposed method can effectively evaluate the complexity of two dimensional CAl)engineering graphics. Finally, the application of the complexity of two dimensional engineering graphics in encryption and watermarking was discussed.

Key words: Two-dimensional engineering graphic, Complexity, Information security