From Bike Collectives Wiki

Chain rings are either held together by rivets or bolts. Avoid owning a bike with chain ring rivets if possible, as you will have to destroy your chain rings and your right crank arm if you need to take apart/ repair the chain rings for any reason.

Taking apart bolted chain rings requires one special tool. It has a notched head designed to fit a chain ring nut. Any bike shop should have them.[1]

See Also