| dc.description.abstract |
In this paper we have used a method for encryption
of images using scalable coding. In encryption, a pseudorandom
number derived from a secret key is used to encrypt the original
pixel values. In encoding block, encrypted data is decomposed
into a down sampled sub image and several data sets with a
multiple-resolution construction. Thus an encoder quantizes the
sub image and calculates the Hadamard coefficients of each data
set that will reduce the data amount. Then, this quantized sub
image and Hadamard coefficients are regarded as a set of
bitstreams. At the receiver end, while decryption of sub image
will give the rough information of the original content, the
quantized coefficients can be decrypted to regenerate the detailed
content with an iteratively updating procedure. At the output we
will first obtain a lossy version of image and images of higher
resolution can be obtained when more and more bitstreams are
received. PSNR of reconstructed images is calculated for all
scales. When more number of decomposition levels are used to
decompose encrypted data, PSNR performance is good. |
en_US |