Create a random bijective function which has same domain and range

Create a random bijective function which has same domain and range. By random bijective function I mean a function which maps the elements from domain to range using a random algorithm (or at least a pseudo-random algo), and not something like x=y. The domain and range can be a very small set sometimes like {1,2,3,4,5}, so a pairing function won't work. Also, computational resources are limited, so it should be a computationaly feasible function.