A hacker sends a company employee a fraudulent email prompting him to change his password. The employee downloads a PDF, which is a keylogger posing as password security guidelines. Once the keylogger has been downloaded, the hacker gets the employee's credentials and logs into the system.
Charlie explains, at a high level, how prime numbers are used in modern encryption. He mentions that solving the Riemann Hypothesis could help decrypt current present day encryption, unlocking passwords and bank account information.