URLcrypt – Encrypted URLs Information with PHP
Now you know how to use PHP to encode information in URLs. You can use this to encode insensitive information, or encrypt *and* encode sensitive information. (This would be a great way to generate URLs with an expiry date, for example.) It would be beneficial to be reminded that URLs should generally not exceed 2,000 characters. Since every 5 bits is converted to 8 bits, we can calculate our overhead factor to be 1.6x, meaning that our new string is 1.6 times as long as our old string (8 bits/5 bits = 1.6).