The cost option is how algorithmically complex the resulting hash will be. The greater the cost, the longer it takes to create the final hash, but the more secu

The cost option is how algorithmically complex the resulting hash will be. The greater the cost, the longer it takes to create the final hash, but the more secure it is. Lower cost = lower secure. Basically you want to use as high of a cost as you can on your servers hardware, without producing a noticeable slowdown to the end user.