The rapid development of data communication in modern era demands secure exchange of information. Steganography is an established method for hiding secret data from an unauthorized access into a cover object in such a...The rapid development of data communication in modern era demands secure exchange of information. Steganography is an established method for hiding secret data from an unauthorized access into a cover object in such a way that it is invisible to human eyes. The cover object can be image, text, audio,or video. This paper proposes a secure steganography algorithm that hides a bitstream of the secret text into the least significant bits（LSBs） of the approximation coefficients of the integer wavelet transform（IWT） of grayscale images as well as each component of color images to form stego-images. The embedding and extracting phases of the proposed steganography algorithms are performed using the MATLAB software. Invisibility, payload capacity, and security in terms of peak signal to noise ratio（PSNR） and robustness are the key challenges to steganography. The statistical distortion between the cover images and the stego-images is measured by using the mean square error（MSE） and the PSNR, while the degree of closeness between them is evaluated using the normalized cross correlation（NCC）. The experimental results show that, the proposed algorithms can hide the secret text with a large payload capacity with a high level of security and a higher invisibility. Furthermore, the proposed technique is computationally efficient and better results for both PSNR and NCC are achieved compared with the previous algorithms.展开更多
针对现有医学图像加密算法在加密效率和安全性上的不足,提出一种基于2D sine logistic混沌映射的医学图像小波域加密算法。算法首先利用整数小波变换将医学图像从空域转换为频域,充分打破像素间的相关性;其次,利用2D sine logistic混沌...针对现有医学图像加密算法在加密效率和安全性上的不足,提出一种基于2D sine logistic混沌映射的医学图像小波域加密算法。算法首先利用整数小波变换将医学图像从空域转换为频域,充分打破像素间的相关性;其次,利用2D sine logistic混沌映射生成混沌序列,选取三级小波分级的低频系数LL3进行扩散和置乱加密,提高加密效率;并且将二级小波分解的中高频系数HL2和LH2进行扩散加密,解决加密图像中存在的明显轮廓问题;最后将加密后的小波系数进行小波逆变换得到加密图像。实验仿真结果表明,算法具有高安全性和加密效率,与现有空域方法相比,加密时间约为1/40;与现有频域方法相比,在保证加密效率情况下具有更好的加密图像隐蔽性。展开更多
文摘The rapid development of data communication in modern era demands secure exchange of information. Steganography is an established method for hiding secret data from an unauthorized access into a cover object in such a way that it is invisible to human eyes. The cover object can be image, text, audio,or video. This paper proposes a secure steganography algorithm that hides a bitstream of the secret text into the least significant bits（LSBs） of the approximation coefficients of the integer wavelet transform（IWT） of grayscale images as well as each component of color images to form stego-images. The embedding and extracting phases of the proposed steganography algorithms are performed using the MATLAB software. Invisibility, payload capacity, and security in terms of peak signal to noise ratio（PSNR） and robustness are the key challenges to steganography. The statistical distortion between the cover images and the stego-images is measured by using the mean square error（MSE） and the PSNR, while the degree of closeness between them is evaluated using the normalized cross correlation（NCC）. The experimental results show that, the proposed algorithms can hide the secret text with a large payload capacity with a high level of security and a higher invisibility. Furthermore, the proposed technique is computationally efficient and better results for both PSNR and NCC are achieved compared with the previous algorithms.
文摘针对现有医学图像加密算法在加密效率和安全性上的不足,提出一种基于2D sine logistic混沌映射的医学图像小波域加密算法。算法首先利用整数小波变换将医学图像从空域转换为频域,充分打破像素间的相关性;其次,利用2D sine logistic混沌映射生成混沌序列,选取三级小波分级的低频系数LL3进行扩散和置乱加密,提高加密效率;并且将二级小波分解的中高频系数HL2和LH2进行扩散加密,解决加密图像中存在的明显轮廓问题;最后将加密后的小波系数进行小波逆变换得到加密图像。实验仿真结果表明,算法具有高安全性和加密效率,与现有空域方法相比,加密时间约为1/40;与现有频域方法相比,在保证加密效率情况下具有更好的加密图像隐蔽性。
