I don't quite understand this one. > If a file is signed and it can be matched against a distributed ledger, it can help ensure the authenticity of the file.

I don't quite understand this one. > If a file is signed and it can be matched against a distributed ledger, it can help ensure the authenticity of the file. So I guess the point is that you don't want to have a central, trusted party. So someone can't simply hack or bribe that party. But what prevents a malicious actor from pushing their file's signature onto the blockchain? If only certain keys are allowed to use for signing, we're back to the trusted party: those with key access. What is the benefit here? > Imagine that all land records are in a distributed ledger. The land owner has a signed certificate that can be verified anytime for authenticity. Is this related to the file authentication thing? Perhaps because I don't know what benefit the former should have, I don't get what this is supposed to have in common. Here too, though, I don't see an advantage of doing it on a blockchain. The department of land records can publish a public key corresponding to the private key they use to sign land certificates: "that can be verified anytime for authenticity."