Abstract: Aiming at the problem of copyright protection for digital engineering drawing and
the deficiency of robustness and practicability of the steganography for digital engineering
drawing, an algorithm of steganography based on dot-matrix character code and entity color for
engineering graphics is proposed. In the algorithm of steganography, the hidden message is firstly
coded by dot-matrix, and the character of the message has the image characteristic property. Then
the coded information is encrypted by a two-value chaotic sequence generated by Logistic map
system. To realize the information hiding and self-checking, the encrypted information and its
checksum are embedded into the entity color of engineering drawing combining with the HVS.
The experiment results show that the algorithm has a higher embedded capacity and a better
robustness for some attacking of moving, rotation and edit. And the problem of copyright
protection for digital engineering drawing is solved in a good way using the algorithm.

Key words: computer application, steganography, entity color, character dot-matrix code;
engineering drawing