Check if an address exist on a ethereum contract in a Joint account in a bank?

Question

I have to make a smart contract that will work similar to a normal bank . I have to do Joint account registration . so , how i am taking two address as input , how do I check whether the user exists or not ?? What i was trying to do is combine both the addresses i.e._address1+_address2 and check if this user exists , but since i am unable to do that . can anyone tell me as to how to proceed ?

Answer 1

If I understand the question properly, you want to track accounts by the combination of two addresses.

keccak256(address1, address2) would make sense, but be careful about the order of the addresses. If order isn't meaningful—(address1, address2) is equivalent to (address2, address1)—then you should sort the addresses first.