As far as I know, riffling and/or shuffling, palm to palm or on a table is fine. Unless you assume the dealer can hide, move, or arrange one or more cards. But

As far as I know, riffling and/or shuffling, palm to palm or on a table is fine. Unless you assume the dealer can hide, move, or arrange one or more cards. But a cut is supposed to fix that. A naive shuffle with a clean table and a clean deck of cards, in the dirt and dust sense, is to put all the cards face down and just smear them around with your hands, then collect them, and deal. If you've ever bought a deck of cards, you know after a hand or two how well everyone can shuffle. There's millions and millions and millions of possible decks, but a fair shuffle is practically guaranteed.