Okay kiddo, so there was a man named Boucher who had a computer. He put a password on it so that nobody else could use it. But the police thought he did something bad on that computer, so they wanted to search it for evidence. They asked him for the password, but he said no. The police couldn't search the computer without the password, so they went to court to ask if it was okay for them to make him give them the password.
The court said that if the police have a good reason to believe there's evidence on the computer, they can make Boucher give them the password. They don't have to worry about the Fifth Amendment's protection against self-incrimination, because the password doesn't come from his mind the way that speaking does. So it's like having a key to a locked box - the police can take the key from him even though they couldn't force him to tell them what's inside the box.
This case helps decide what the law should be about digital privacy and police searches of computers.