中文摘要：

针对目前协同设计过程中信息安全风险,从提高CAD模型的安全性出发,提出一种基于CAD特征模型局部变形的敏感信息保护方法,通过对草绘参数进行变换,使模型几何形状发生变化,达到隐藏原模型信息的目的;然后提出了基于加密矩阵的草绘参数加密技术,采用一个加密矩阵作为秘钥对草绘中的控制点参数进行加密转换;进一步,为更好地控制加密后模型的变形趋势,引入几何计算中的自由变形方法,使用加密控制晶格对草绘进行加密,提出基于自由变形的草绘参数加密方法.最后通过对CAD零件模型进行实验,证明了文中方法的有效性..

英文摘要：

To enhance the security of CAD model in collaborative design, firstly, the architecture of sensitive information protection is proposed based on partial deformation of CAD model. Sketch parameters are transformed to deform the shape of CAD model to hide original model information. Then, an encryption matrix method is presented to encrypt control points of sketch by using the matrix as the encryption key. Further, in order to control the deformation tendency of encrypted model, a Free Form Deformation（FFD） based encryption method for sketch is introduced from geometry computation into feature based CAD systems. This method applies an encryption lattice to encrypt sketch. Finally some case studies were made to demonstrate the method.