References-to-SO-question

[1]Php implementation: http://stackoverflow.com/questions/14975898/instagram-how-to-verify-x-hub-signature-in-php

[2]Python implementation: https://github.com/Instagram/python-instagram/blob/master/instagram/subscriptions.py#L53

[3]Ruby implementation: https://github.com/Instagram/instagram-ruby-gem/blob/master/lib/instagram/client/subscriptions.rb#L131

[4]Instagram developer website: http://instagram.com/developer/realtime/#

[5]https://groups.google.com/forum/#!msg/play-framework/YMQb6yeDH5o/jU8FD--yVPYJ