Support discovery & peering with untrusted nodes

[CDDelta]

For my use case, I want to be able to discover and peer with untrusted Arweave nodes to retrieve data as opposed to defining my own list of trusted nodes.

To do so, the gateway will need to first discover nodes to peer with then it will need to verify that the data it receives from those nodes are correct.

• Blocks can be verified to be valid by checking that a majority of the peers agree on it (that's my understanding at least)
• Transactions and their inclusion in blocks can be checked with the blocks that have been indexed (though how this works in block format v3 is a bit less obvious to me).
• The actual transaction data can be verified for ANS-102 unbundling and client streaming using the generateTransactionChunksAsync() function I wrote here. Though for client streaming whether or not the data is valid can only be known once the entire stream has completed.

[samcamwilliams]

Very nice idea. Would love to see this.

Blocks can be verified to be valid by checking that a majority of the peers agree on it (that's my understanding at least)

Not even necessary -- just validate the deephash of the block structure you are given matches its ID.

PRs welcome!!

[CDDelta]

Not even necessary -- just validate the deephash of the block structure you are given matches its ID.

Ahh, I phrased myself wrongly here. What I meant was the gateway needs to somehow check that the block it has is the longest chain/the one miners will extend.

I believe the only way to do this is to check with node peers?