FYI -- MD5 hopelessly broken: http://natmchugh.blogspot.co.uk/2014/10/how-i-created-two-images-with-same-md5.html "How I created two images with the same MD5 hash" I posted the following images the other day which although looking totally different have exactly the same MD5 hash (e06723d4961a0a3f950e7786f3766338) .