How to retreive airport wpa2 key on imac late 2012 fusion drive

The "key" is a 64 character phrase consisting o a mix of letters and numbers. I can't think of any time that the "key" would be required. Are you sure that you are looking for the "key" and not the "password"?

What is it exactly that you are trying to accomplish? If you find the "key", how will it be used?

Do you still have the AirPort router operating on your network? If yes, you might be able to retrieve the data using AirPort Utility on your Mac.

If you have an AirPort router operating on your network, you can retrieve the wireless network "key", but I don't know how you would ever use it.

Post back if you want to see the "Key"