Quote from: TPTB_need_war on February 17, 2016, 08:49:41 PM

Isn't the simple solution to include the signature of the entire document with each chunk you forward. If the signer claims he provided different text, he will need to produce a document which matches the hash of what he signed, but he can't do that and also lie.

There are usually simpler solutions. Just think out of the box and paradigm shift the problem.

I think the issue is that the originator of the data might be antagonistic and not cooperate and put the burden on the intermediary, but it is a good idea to include the signature in the hash of each sblock.

I think just using field multiplication of N different hashes for each sblock will allow to achieve whatever confidence level about collisions, at the cost of more space for this though. Using curve25519 field multiplication is VERY fast. Probably will do more than a million per second on a single core. The limitation will probably be HDD speeds loading the data or the sha256 calcs

James

P.S. Not sure it can get much simpler than 300 lines of C code...