What's the best way to create a short hash, similar to what tiny Url does?

Question

I\'m currently using MD5 hashes but I would like to find something that will create a shorter hash that uses just [a-z][A-Z][0-9]. It only needs to be around 5-

Answer 1

Just take a Base36 (case-insensitive) or Base64 of the ID of the entry.

So, lets say I wanted to use Base36:

(ID - Base36)
1 - 1
2 - 2
3 - 3
10 - A
11 - B
12 - C
...
10000 - 7PS
22000 - GZ4
34000 - Q8C
...
1000000 - LFLS
2345000 - 1E9EW
6000000 - 3KLMO

You could keep these even shorter if you went with base64 but then the URL's would be case-sensitive. You can see you still get your nice, neat alphanumeric key and with a guarantee that there will be no collisions!