Image Encryption Assignment
This is an interesting assignment set for postgraduate students in the field of ICT. The work is based on the analysis of AES-Rijndael and RC6 block ciphers for digital images. Here are sample abstracts of their work, your comments are welcomed. Detail assignment papers are provided upon request.
By Hemraj Ramsurrun
Visual inspection is not sufficient to analyse the encryption
efficiency of a given algorithm. This paper describes three main
mathematical models: Maximum Deviation, Correlation
Coefficient and Irregular Deviation, as proposed in [1] and [2],
used to evaluate the encryption quality of the RC6 and AES
Rijndael block ciphers when applied to digital images. These
models are centered on the fact that encryption brings a change in
the pixel values of the images and exploit this change to judge
quality of encryption. The results are quoted from the two
reference papers based on which, a few observations are made.
AES Rijndael and RC6 were applied in three modes of operation
namely: ECB, CBC and OFB. It was found that both RC6 and
Rijndael offer good encryption quality with Rijndael being
slightly better. The results obtained in the ECB mode were found
to be less interesting while the Irregular Deviation measuring
factor proved to be most efficient to assess encryption quality.
By S. Ramsaha
The main objective of this work is to study the
encryption efficiency of AES Rijndael algorithm for digital
images by comparing it to RC6. Firstly, the importance of
image encryption is emphasised followed by a review of
Rijndael and RC6 algorithms. Different Bitmap images are
encrypted using the two algorithms based on electronic code
book, cipher block chaining and output feedback modes. The
encryption efficiency is then evaluated based on metrics like
maximum deviation measuring factor, correlation coefficient
measuring factor, irregular deviation measuring factor. Also,
other important metrics like encryption time and throughput
are considered.
By Shobna Jadunundun
Encryption is the most trusted practical security technique to protect users‟ sensitive data especially for multimedia transmission. Consequently, several algorithms have been developed; RC6 and Rijndael being among the most popular. To verify the encryption quality of these two algorithms when applied to different types of bitmap images for example, visual inspection alone is insufficient. Hence, three measuring factors have been considered based on the fact that encryption brings an irregular change in the pixel values of an image. These are Maximum Deviation, Correlation Coefficient and Irregular Deviation and have been used to evaluate the encryption quality of the two block ciphers operated under three modes namely: Electronic Code Book, Cipher Block Chain and Output Feed Back. Discussion of results is taken from those given in papers [1] and [2] and some recommendations have also been suggested. The observations made show that CBC and OFB are better than ECB in hiding image features. Irregular deviation can be used as the only metric to evaluate encryption quality as the results obtained are more conclusive than those of the other two metrics.
