A Multiple Encryption Algorithm for 2D Engineering Graphic Based on Fourier Descriptors and Chaos Scrambling

A multiple encryption algorithm is proposed for 2D engineering graphic based on Fourier descriptors and chaos scrambling. The specific coordinates of vertices in the 2D engineering graphic are extracted to construct the corresponded complex signals, which are in turn transformed by Fourier transformation, then bit XOR operation is used between the FFT magnitude coefficients and a binary sequence, which is generated from chaotic system, At last, chaos scrambling (translation, rotation, zooming) is done to the entities of the 2D engineering graphic. That is the encryption of the content of the 2D engineering graphic. Simulation and analysis results show that the key space is large, and the algorithm is sensitive to the key, plain graphic and encrypted graphic, which guarantee the security of 2D engineering graphics.