when we sign a message, we can retrieve the pubkey from the sig
Why the bitcoin does not use the same technique in tx signature?
so the transaction would be smaller because you wouldn't have to contain the pubkey
It has been briefly talked about before. The issue is the additional overhead required to do so. Someone could give you a bunch of invalid transactions so you need to spend a lot of computing power to get the pubkey and then check that that maps to the address. That could become a DoS attack. The current system does the low computational cost action first of hashing before the more intensive task of verifying.
