Hacking ATMs: The Difficulties of Sharing Information

1. Hacking ATMs: The Difficulties of Sharing Information Presented by Eli Kosminsky

2. How an ATM Works Dispense Cash Check Balance Transaction Done Record Balance “Withdraw $100” Read Balance Update Balance Write Balance

3. What Happened? “He’s got $100…I’ll dispense it for him.”

4. What’s the Problem? • We can’t have multiple ATMs making withdrawals at once • We need to improve communication between ATMs

5. Learning from Literature

6. New Idea: Locks • A lock is like a conch shell • They both say “it’s my turn to use this”

7. How an ATM Works Transaction Done Dispense Cash Check Balance Record Balance Read Balance “Withdraw $100” Return Lock Take Lock Update Balance Write Balance