He becomes Malky's third signing this summer and will compete with David Marshall and Joe Lewis for the No.1 shirt this season.
Speaking to Cardiff City Player he said
"I'm delighted to be at Cardiff City - to play in the Premier League has always been my goal.
"It's exciting to think that I'll be working with quality goalkeepers like David Marshall and Joe Lewis on a daily basis and I know that I can develop and learn from them."
Moore played 52 times for Brentford last season.
Wecome to Cardiff City.