I think it will simply become impossible to keep digital payment systems secure. The whole online economy will collapse. Amazon will become worthless. People will actually have to go out to local stores to buy everything. People will have to go to their local bank or currency exchange to cash their paychecks. The credit card system will fail completely too, while payday loans will take their place. The stock market will have to go back to traders yelling their trades to each other at exchanges. The old ways will become new.
AI can’t be smart enough to break math.
No amount of AI processing can draw a triangle whose angles add up to more than 180°, factor a prime number into integer factors, find the square root of a negative number without using imaginary numbers, etc.
If the protocol and the cryptography is secure, no amount of smarts can overcome that security. If something is insecure, someone will probably figure it out (with or without the help of computers and AI) and take advantage of it until it’s patched.
Any cryptography can be broken with enough computing power and time, but that is beside the point. You don’t have to pick the lock if you can just climb through an open window. You get what I am saying?
There are loads of other ways to get credentials besides cracking encryption. Hell, wifi signals can be used to read the motions of a person’s hands over a keyboard with 90% accuracy. https://www.securityweek.com/researchers-use-wifi-signals-read-keystrokes/