Generate a unique string out of numeric value
This is how you can create a (pretty) unique string that changes constantly, mening not being almost the same as the previously generated string. I needed something that needs to be unique for a year and not look the same as the previously generated string/key, and that was not that very obvious that it was based on the unix timestamp. So I removed the first digit, to keep it short, you could keep that unique over the years if needed. Then I added the first digit in the microtime() result, to make it generate at least 10 different keys per second.