2263
The malicious programs encrypt the infected computers ’ files , and users can only open them after paying the perpetrators money to obtain a special key to unlock them .
 ( ransom: paying,  the perpetrators: attacker, encrypt the infected computers ’ files: attack pattern, users: victim, The malicious programs: tool) 
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: paying,  the perpetrators: attacker, encrypt the infected computers ’ files: attack pattern, users: victim, The malicious programs: tool) 