What is the best way of hiding or encrypting information in comments in Javascript, CSS or HTML code?

While digging through facebook's css and html code I found some comments which seems to be encrypted in order to hide information. This could be some kind of debugging information which might be useful to keep for later use. The comments are looking like this example:

/*[XnbHYrH~LGxMu]p`KYO^fXoOK]wFpBtjKdzjYssGm~[xISvmX0J]xhEMxwV_NjvnWm]jAyo`@}VtxqZ{QC`M|yxHMBLE[ZsaeCgU[aG}|K|`Icu`hxiAzM|j~RRkiO|AF`_KuuEnfd_I[P}BDo`ykXBjUjt_nza@^hh?CEQp~KHR|z`llKuTxM_lJp*/

A quick analysis of the encrypted text with this python snippet ''.join(sorted(set(comment))) shows that only 64 different characters are used.

'0?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[]^_`abcdefghijklmnopqrstuvwxyz{|}~'

In terms of performance, size and browser-compatibility one cheap approach would be a base64 en开发者_JAVA百科coding of the raw text with a custom char mapping.

Update: Some of the constraints I would define for a best solution is a fast encoding with low computation time and a small output size for reduced bandwidth. On the other side it should be easy to retrieve the original information with a script and some kind of secret if needed. The usage is more for hiding non-sensitive data, so there is no need for strong encryption. It just should be economical unattractive for someone spending time on it.

I use a huffman code and base64 to encode some data on my website. I think it's very hard to bypass and I get some compression too. That was more an accident I did. But it would be nice if you can explain how you define best in this context? Do you have constraints?

I don't know what they're doing here, but I'd say you should never intentionally send sensitive data or anything you want to hide to a client, regardless of whether it's encrypted or not. Not only is it dangerous (if by some chance your encryption is broken) but it is wasting bandwidth.

If you absolutely need to keep stuff in your sourcecode for some reason, then you should have a pre-release job to strip it out so it never gets published.