shortest encoding for Guid for use in a URL

Question

The top result on google http://csharpfeeds.com/post/4382/A%5Fshorter%5Fand%5FURL%5Ffriendly%5FGUID.aspx will get one down to 00amyWGct0y_ze4lIsj2Mw

Can it go smaller than that?

Answer 1

A GUID looks like this c9a646d3-9c61-4cb7-bfcd-ee2522c8f633 - that's 32 hex digits, each encoding 4 bits, so 128 bits in total

A base64 encoding uses 6 bits per symbol, which is easy to achieve with URL safe chars to give a 22 char encoded string. As others have noted, you could with with 73 url safe symbols and encoded as a base 73 number to give 21 chars.

Answer 2

Guid can be represented as byte array, use Base64 encode to convert it, so it would be little bit shorter.

Answer 3

Looks like there are only 73 characters that can be used unescaped in a URL. IF that's the case, you could convert the 128-bit number to base 73, and have a 21 character URL.

IF you can find 85 legal characters, you can get down to a 20 character URL.