Security(Tampering encoding) in Old and New URLs

[atrope]

Hi All,
I've implemented old thumbor feature of having a hash on each url.
It works on old urls (thumbor format) and also new urls base64 encoded(I've added the parameter "hash" to the object).
I Got the base function from the PR here: #111 (thanks to @soupy1976)
I've implemented in a rush, so it is not ready for PR yet but I was thinking if there is a need to make a proper PR or is it a thing that not all people need?
The way we have, We only check for the key if there is the SECURITY_KEY env variable, giving the user the choice.

Let me know if a PR is needed.

Thanks

[piecedata]

Hi @atrope, it will be cool if you can share this. Thanks

[beomseoklee]

Thanks for your inputs and waiting for the response. We've added the feature to meet this request in v5.1.0, so please take a look at the latest one.