摘要
多像素加密视觉密码(multi-pixel encryption visual cryptography,MEVC)将多个秘密像素作为基本块,并将秘密块映射到分享图像的包含相同像素数的块中,以解决传统视觉密码方案中的像素扩展。现有的多像素加密方案往往伴有生成的分享是无意义的类噪声图像的问题,分享图像伪装性差,在存储与传输过程中易于被攻击者识别。同时,已有的有意义分享的多像素加密方案中存在无彩色图像、算法扩展性差、恢复图像受掩盖图像干扰等诸多问题。据此,本文提出一种有意义分享且无像素扩展的彩色(2,2)视觉密码方案,选取相同大小的秘密图像与掩盖图像,采用多像素加密的方法,以秘密块作为单位进行加密并将加密信息嵌入到掩盖图像中,并利用半色调技术对携带秘密信息的掩盖图像作处理,最终生成有意义的分享图像,提高了多像素加密方案的安全性。实验结果表明,本方案具有彩色的秘密图像和掩盖图像、分享图像无扩展且有意义、恢复图像无掩盖图像干扰等特点,分享图像与恢复图像具有良好的视觉效果且满足安全性要求。
In multi-pixel encryption visual cryptography(MEVC),multiple secret pixels are treated as basic blocks and the secret blocks are mapped to the blocks containing the same amount of pixels in the shared image to solve the issue of pixel expansion in the traditional visual cryptography scheme.Existing multi-pixel encryption schemes often suffer from the meaningless and noise-like generated shared image,and the shared image has poor camouflage and is easy to be recognized by attackers during the storage and transmission.Meanwhile,existing multi-pixel encryption schemes with meaningful share are troubled by the issues of achromatic image,poor algorithm scalability,disturbance from the cover image during the image restoration,etc.To address the issues,in this paper a color(2,2)visual cryptography scheme with meaningful share and no pixel expansion is proposed.In the scheme,the secret image and the cover image have the same size,and the method of multi-pixel encryption is adopted.The secret block is encrypted as a unit and the encrypted information is embedded into the cover image,and the halftone technology is utilized to process the cover image carrying the secret information.Finally,meaningful shared images are generated to improve the security of the multi-pixel encryption scheme.Experimental results show that the proposed scheme has the characteristics of color secret image and cover image,meaningful shared image without expansion,and no disturbance from the cover image during the image restoration.The shared image and restored image have good visual effect and satisfy the security requirements.
作者
韩妍妍
周义昆
刘欣阳
HAN Yanyan;ZHOU Yikun;LIU Xinyang(Xidian University,Xi’an 710071,P.R.China;Beijing Electronic Science and Technology Institute,Beijing 100070,P.R.China)
出处
《北京电子科技学院学报》
2022年第1期62-74,共13页
Journal of Beijing Electronic Science And Technology Institute
关键词
视觉密码
彩色图像
无像素扩展
有意义分享
visual cryptography
color image
no pixel expansion
meaningful share
