  Encryption-then-Compression (EtC) systems have been proposed to securely
transmit images through an untrusted channel provider. In this study, EtC
systems were applied to social media like Twitter that carry out image
manipulations. The block scrambling-based encryption schemes used in EtC
systems were evaluated in terms of their robustness against image manipulation
on social media. The aim was to investigate how five social networking service
(SNS) providers, Facebook, Twitter, Google+, Tumblr and Flickr, manipulate
images and to determine whether the encrypted images uploaded to SNS providers
can avoid being distorted by such manipulations. In an experiment, encrypted
and non-encrypted JPEG images were uploaded to various SNS providers. The
results show that EtC systems are applicable to the five SNS providers.
