This is a legal connection, but barely. Minimum connection for US to international in YVR is 60 minutes. See https://www.aircanada.com/us/en/aco/home/plan/check-in-information/minimum-connection-times.html
You have to clear Canada immigration, but you should not need to go through security again. If all goes well, you should be able to make it, but if custom lines are long and/slow or if your inbound is delayed, you'll miss it. If you do miss, Air Canada will rebook you on the next flight which may be at a later date.
- Try to sit in front of the US to Canada plane and/or plead with the flight attendants to let tight connections get out early. Get an isle seat so you can actually can run for it, if you get the chance
- Get your boarding passes ahead and print them. In a hurry, paper is faster then trying to connect to the Internet in a different country.
- Look up arrival and departure gates on a map and try to picture the way in your head
- If immigration is long or slow, try to beg your way through the line. I had to do this once in Ottawa and most other passengers were sympathetic and let me pass. Border control officer were no help at all!
- Make sure you have your Canada paperwork completely filled out before arriving at the booth. Maybe you can already print one ahead and fill it out. See https://www.cbsa-asfc.gc.ca/publications/forms-formulaires/e311-eng.pdf
Connecting in Canada is always a major hassle. The form asks for "duration of stay in Canada" and I'm always tempted to write "Only another 45 minutes, but only if you can do your job promptly". Probably not a good idea :-)