  With the enormous usage of digital media in almost every sphere from
education to entertainment, the security of sensitive information has been a
concern. As images are the most frequently used means to convey information,
therefore the issue related to the privacy preservation needs to be addressed
in each of the application domains. There are various security methods proposed
by researchers from time to time. This paper presents a review of various image
encryption schemes based on fractional integral transform. As the fractional
integral transforms have evolved through their applications from optical signal
processing to digital signal and digital image processing over the decades. In
this article, we have adopted an architecture and corresponding domain-based
taxonomy to classify various existing schemes in the literature. The schemes
are classified according to the implementation platform, that may be an optical
setup comprising of the Spatial modulators, lenses and charged coupled devices
or it can be a mathematical modelling of such transforms. Various schemes are
classified according to the methodology adopted in each of them and a
comparative analysis is also presented in tabular form. Based on the
observations, the work is converged into a summary of various challenges and
some constructive guidelines are provided for consideration in future works.
Such a narrative review of encryption algorithm based on various architectural
schematics in fractional integral transforms has not been presented before at
one place.
