[sangnoir]

> For example, such a ledger can be used to create a tamper-proof security-camera footage log.

What's the use-case here - who are the untrustworthy individuals that society needs to protect itself against? Societal trust is currently rooted in people - it will not be switched over to machines/distributed ledgers any time soon. This is why people can write affidavits/get sworn in to say "That video's legit" under pain of perjury. Frankly, there's little money in turning over trust to a blockchain when there is an individual/organization that can be interrogated. It's not perfect, but trying to perfect it has (evidently) diminishing returns

[derefr]

That example is not about positive proof (i.e. proving that real evidence is real); it's about negative proof (i.e. proving that fake evidence is fake.) It's about having a way to figure out that the expert defending the evidence has been bribed, and is saying what the prosecution wants them to say.

You can't charge someone with perjury if you can't prove the faked evidence is faked—which is why so few people get charged with perjury. Any threat of perjury with no discriminatory proof mechanism to back it up, is toothless, and experts will treat such threats with exactly the respect they deserve. (Look at the Japanese court system if you don't believe me.)