513
The hacking tool spreads silently between computers , shutting them down by encrypting data and then demanding a ransom of US$ 300 to unlock them .
 ( ransom: demanding a ransom,  The hacking tool: tool, computers: victim, shutting them down by encrypting data: attack pattern, US$ 300: price) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: phishing, data breach, ransom, discover vulnerability, patch vulnerability, Arguments type: vulnerable system, capabilities, vulnerability, number of victim, issues addressed, compromised data, damage amount, common vulnerabilities and exposures, victim, patch number, number of data, tool, discoverer, time, purpose, place, payment method, releaser, vulnerable system version, attacker, supported platform, patch, price, vulnerable system owner, trusted entity, attack pattern. 
Text: {0} 
Answer:
 ( ransom: demanding a ransom,  The hacking tool: tool, computers: victim, shutting them down by encrypting data: attack pattern, US$ 300: price) 