How to generate a 64 bit key in php [closed]

Question

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.

Closed 9 years ago.

I have been trying up with random number generators in php to generate keys for photos structure on the website I am building. I recently came to know that Facebook as well as Instagram fit there photo ids in 64 bit.

Facebook Engineering Note -: http://www.facebook.com/note.php?note_id=76191543919 Instagram Engineering Note -: http://instagram-engineering.tumblr.com/post/10853187575/sharding-ids-at-instagram

Just wanna know how these guys do it and fit various aspects like user id, timestamp in various bits to come up with 64 bits in total.

Any help would be greatly appreciated

Answer 1

Try looking at this:

64 bit key

Now just replace random counter with current timestamp.