monson

> you'd be unwise to think that your cryptographic signatures are going to help much

It was you who suggested simple cryptographic signatures in your initial reply to the parent comment. I was only pointing out that securely signing a message with a timestamp requires a cryptographic entity known as a "Trusted Third Party". Please see the first link in my original comment.

> That would be the judiciary. If they -- the people with the guns and the resources of the state -- become corrupted, you'd be unwise to think that your cryptographic signatures are going to help much.

If there was verifiable proof on a globally distributed blockchain that evidence had been tampered with by a judiciary member of a democratic country, I find it very hard to believe they would get away with it in the long term.

Securely signing a cryptographic message with a provable timestamp still requires a trusted third party, as far as I know. A trusted third party can be corrupted.[1]

Writing data on a decentralized blockchain inherently provides a secure timestamp that cannot be modified without being noticed. Not to mention the extreme costs involved with trying to rewrite a blockchain's history. [2]

I disagree with the parent comment on one thing-- I would much rather trust a public blockchain with a respectable hashrate over a private blockchain. You could simply store a salted hash of the data on the public blockchain, and still keep the actual evidence private.

[1] https://en.wikipedia.org/wiki/Trusted_third_party [2] https://en.wikipedia.org/wiki/Trusted_timestamping