Re-inventing the wheel? Regarding Query String

[bri189a]

Has anyone seen anything out there that 'validates' a query string - i.e. ensures that the user hasn't altered the contents of the QueryString - for example on this page:

 

http://www.xtremedotnettalk.com/newthread.php?do=newthread&f=62

 

I could change the f=62 to f=54 to enter a new thread on the Windows forum.

 

Now let me say before anyone tries to correct me, that I know there are other ways around the situation - I've just found a caveat in those other ways that can be worked around, but implementing my idea would be easier - IMO; it's clever, but clever isn't always good.

 

I'm just trying to find out if someone has already done this and I'm wasting my time....what if I digitally signed the query string? In otherwords use a keyed hash algorithm, passing that hash value in the query string to make sure the other values in the query string weren't tampered with? I've already designed it out and I think it will be pretty cool, but as any good coder knows, just because it's cool doesn't mean it's useful. :)

 

Would other people find this valuable if no one else has ever done it?