Yes it is the last step. Do you know if your eligibility has passed? It could be they are still reviewing your eligibility - your security check will only be initiated after the case analyst's done reviewing all your docs and recommends a pass on eligibility.
Security is checked against a few databases to detect any association with terrorism and what not. Legalfalcon had a very detailed post explaining the application process and what's being checked in each step. I don't have the link but should be pretty easy to find.
thanks for the reply. i am not sure if the eligibility passed. i called cic , the agent mentioned my medical looked good i dont remember if she mentioned my eligiblity but security not started as she said.