The Shutdown Problem: How Does a Blockchain System End?

I don't see this as an issue. If the chain is important enough, it will continue on from usage. If it's not useful enough to keep alive, then why bother with keeping it alive as a mean of archiving it?

I remember when I thought FlappyCoin was going to be as big as Dogecoin. Nope! I wonder what happens with a devalued Altcoin. I read through the article and the gist seems to be that a 51% attack is possible. I wonder if this has been pulled off with any that were at one time popular. If I were a flappycoin millionaire it would bother me if someone had taken my coins even if they had no monetary value. I imagine some others would be more annoyed than I would be.

This isn&#x27;t a shutdown problem. That&#x27;s getting the directionality confused.<p>This is actually the failure mode of most altcoins in the wild. They get attacked because the consensus was never reliable.<p>There are still tons out there (easily more than 50% by number) that could be smashed into oblivion by anyone with a decent amount of money tomorrow.

Have N self-appointed archivists publish a timestamped record of the blockchain. Any query can then be based on N of these archivists.<p>I&#x27;d imagine such a record to be: the final block header, and a Merkle tree root hash of every block using a more time-resistant hashing function. The Merkle tree root hash prevents rewriting the chain later through brute force. The actual consensus mechanism has prevented wrong writes.<p>Timestamping could be done by publishing in newspapers, or in other blockchains.<p>The biggest issue comes at the moment &#x27;archiving&#x27; is announced. History-rewrite attacks then suddenly become a lot more valuable, so you&#x27;d probably need to say &#x27;We are archiving the chain as of 100 blocks ago&#x27;. This prevents anyone from mucking with the end of the chain, but comes at the cost of discarding the last 100 blocks.

Seems like every blockchain should have a baked in “genesis” procedure and “felling” procedure (yep, a logging term since you’re “severing” the Merkle tree) to tie up all sources of new transactions and stumping or “tarring” the blockchain. Sureley there’s fantastic logging vernacular to draw from to name the period between the start of a “felling” and the resultant stump.

1) you could just post the last block ID to an active blockchain or centralized data store if you must, then anyone can download the blockchain via a torrent for example and verify the entire chain; this just requires some trusted data store. If you don’t have one, then you are screwed anyhow and probably shouldn’t have shut down that blockchain.<p>2) if there is utility in the blockchain, chances are it won’t shut down.

By consensus?

&gt; 2. The elements of the sequence are data blocks that are chained together via digital signatures.<p>This is incorrect. Digital signatures are used when (S) signing a transaction which must refer some precious transaction with a receiver address corresponding to the public key which verifies signature S.<p>Blocks are chained by their headers hashes. There are no keys nor digital signatures involved here..