WordNet sense 1 (a formal declaration that documents a fact of relevance to finance and investment; the holder has a right to receive interest or dividends):

certificate, certificate

WordNet sense 2 (property that your creditor can claim in case you default on your obligation):

surety

WordNet sense 3 (defense against financial failure; financial independence):

protection

WordNet sense 4 (a department responsible for the security of the institution's property and workers):

security department

WordNet sense 5 (an electrical device that sets off an alarm when someone tries to break in):

security system, security measure

WordNet sense 6 (measures taken as a precaution against theft or espionage or sabotage etc.):

security measures