550
" A part of carefully planned large - scale ransomware attack requires a separate bitcoin address for each victim , guaranteeing the miscreant controlling the operation would later be able to identify the payment and decrypt the correct system , " wrote security expert John Wetzel in a blog post .
 a separate bitcoin address: payment method; victim: victim
Given event type and trigger, please tell me the arguments of all the listed option. Output format is "name1: role1; name2: role2". 
Event type: ransom 
  Option: victim, attacker, payment method, attack pattern, damage amount, tool, time, price, place 
Text: {0} 
Answer:
 a separate bitcoin address: payment method; victim: victim