It could also be signed using SSL or GPG or really just any other kind of PKI. In the end I need to establish a root of trust, so I either way I need to know th

It could also be signed using SSL or GPG or really just any other kind of PKI. In the end I need to establish a root of trust, so I either way I need to know that 2c414...2d7 is indeed the hash of the chain_address/ssl_cert/root_ca/gpg_key/... - so in that regard there is no advantage of using a blockchain over a "traditional" PKI. Amend: The real question is how to verify cropped and recompressed snippets. In academia or HN we add a "see foo et al. [1]", so probably that needs to be encoded into the data stream, e.g. "authoritative src is https://media.whitehouse.gov/permanent-url/1234 https://media.whitehouse.gov/permanent-url/1234[...] with hash $hash signed by $cert_hash on $data, portions are $some_encoding_here" and better be signed as well.