How Does Trent Send a Cipher Message to Bob, Alice and Carol, And Not Know What Reads the Message?

Let’s say that the Trent wants to send Bob, Alice and Carol a secret message, but where Trent cannot determine who will actually read the message. In this case we will generate key pairs for Bob, Alice and Carol, and Trent will encrypt a message for them. We will then use one of the private keys to decrypt the encrypted…