[TimJRobinson]

Lol, well yea if you throw away the zero knowledge part or trust the client to tell the truth of course you don't need zero knowledge proofs. Its not zero knowledge though (you just gave the server the info) and/or isn't proving anything.

This is the situation zero knowledge proofs are used in:

- The client doesn't trust the server and doesn't want to give it any info (that's the zero knowledge part)

- The server doesn't trust the client (that's the proof part)

If you break them of course the problem is much easier to solve.

If the client trusts the server they can give it a scan of their passport.

If the server trusts the client to run that code then you don't need a proof, you may as well just have a popup that says "are you over 21?"

A rainbow table is just breaking the hash and then you may as well not have it, in the real world the client would add a salt so this isn't possible.