1848
Carleton was the victim of a ransomware attack in November of last year , which locked down dozens of computers that would only unlock if the university paid a ransom in bitcoin .
 ( ransom: paid a ransom,  the university: victim, in bitcoin: payment method, locked down dozens of computers: attack pattern) 
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: paid a ransom,  the university: victim, in bitcoin: payment method, locked down dozens of computers: attack pattern) 