can I encrypt my LaCie external hd…then easily un-encrypt it if I choose?

I’m running OS 10.8.5 on an iMac i7

I’d like to safely store and protect the contents of a LaCie LART1.5TB Rugged Triple Interface USB 3.0 Portable Hard Drive.)

If I do encrypt it, then decide to un-encrypt it, is this easily accomplished by using the password I created when initiating the encryption? I’m a bit leery as the encryption window in Finder reads, ‘This operation cannot be cancelled.