摘要：

针对GIF图像的编码特点，提出退化和保密2种模式下的图像选择加密算法。对于退化模式，采用子集内置乱索引的方法实现对图像退化的可视度控制，对于保密模式，通过加密较少数据实现对整个图像的保护。分析结果表明，该算法在满足GIF图像安全性和格式兼容性要求的同时，使其压缩率保持不变。

关键词: GIF图像选择加密, 退化模式, 保密模式, 格式兼容性

Abstract:

Aiming at the coding characteristic of GIF image, this paper presents an image selection encryption algorithm under degradation and confidentiality modes. Intra-set shuffle index method is used to control image degradation visibility for degradation model. It encrypts only fractal of the image, the whole image is protected for confidentiality model. Analysis results show that this algorithm can meet the requirements of security, format-compliance, and it also can constant compression-ratio.

Key words: GIF image selection encryption, degradation mode, confidentiality mode, format compatibility

中图分类号: 

• TP309