Doesn’t chip and pin do this already?
Also, even with signatures you still need some way to reverse errant and malicious charges. Cryptography isn’t a panacea for solving all real world problems.
Also, even with signatures you still need some way to reverse errant and malicious charges. Cryptography isn’t a panacea for solving all real world problems.
Maybe some kind of USB/Bluetooth device that can authorize your physical debit card can let online merchants debit bank accounts securely. I know they have had something similar in the UK for decades.