@dgar

I have an idea of how you could play federated blackjack.

The dealer makes a random shuffle. They send a hash of it to the player.

Then the dealer and player do a diffie-hellman key exchange to create a random number. The dealer re-shuffles the shuffled cards using this as the random seed.

Then we play in the clear: The dealer sends the next card, the player sends their choices.

At the end, the dealer sends their chosen random shuffle in the clear, so the player can validate.