  Fractional Fourier transform and chaos functions play a key role in many of
encryption-decryption algorithms. In this work performance of image
encryption-decryption algorithms is quantified and compared using the
computation time i.e. the time consumption of encryption-decryption process and
resemblance of input image to the restored image, quantified by MSE. This work
proposes an improvement in computation-time of image encryptiondecryption
algorithms by utilizing image compression properties of the 2-dimensional
Discrete Wavelet Transform (DWT2). Initially, computation complexity of the
algorithms is evaluated and compared with that of existing algorithms. This
analysis claims the proposed algorithms to be nearly 8 times faster than the
existing algorithms. Further, simulations are performed using MATLAB7.7 to
quantify performance of existing algorithms and the proposed algorithms using
MSE and computation time. The results obtained in these simulations prove that
for the proposed algorithms MSE between restored and original images is lesser
than that of existing algorithms thereby maintaining the robustness of the
existing algorithms. These algorithms are found sensitive to a variation of
1x10-1 in the fractional orders used in encryption-decryption process.
