Hyperledger Fabric Channels

Question

I am trying to set up a network where private transactions can be sent, but are a part of a single blockchain, such as is implemented in Quorum with the privateFor parameter when creating a contract.

I could implement a solution using channels and from reading the guides, document and whitepaper I can see that each channel owns its own blockchain. What I'm unsure about is if each channel is again apart of a larger blockchain that will contain the encrypted data of all channels or a hash of each channel when a new block is created.

I can't find any documentation of such a feature so I am assuming that each channel's blockchain is isolated entirely from the rest of the network. This leaves me with three questions.

A) Am I correct in assuming there is no "master" blockchain containing all channels?

B) If I am correct about my assumption, does this not leave channels with only two participants, or one participant if someone leaves, open for an attack as someone could easily change the data stored in the ledger in this scenario?

C) If you were to implement channels for all nodes that need to send private data to one another, wouldn't this increase maintenance hugely i.e creating auditing nodes for each channel etc?

Thanks!

Answer 1

 Hi ,let's take your question step by step

• A) Correct
• B) Fabric is a permissioned blockchain. All participants are known to one-another, and there are no anonymous interactions. Even if a rogue peer were to try to change the ledger such that in the event that the other peer needed to recover its state via state transfer, the transactions would have to undergo the same validation that they do when received from the orderer, so no.
• C) Not sure I understand what maintenance you mean. A peer can
  participate un multiple channels, so adding channels does not increase the number of peers. It would increase the number of ledgers, so in that regard, if you are performing backups etc then there may be additional operational management overhead.  

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