Tag: round robin

MultiChain Mining

In MultiChain, block creators must prove their identity by signing blocks

Block signatures

Block signatures are embedded inside the OP_RETURN metadata of the coinbase transaction, using a regular bitcoin-style signature format. The payload signed by the block creator is the full block header, with the following modifications:

  • The merkle_root is recalculated based on the txid of the coinbase transaction with the OP_RETURN removed. This prevents a dependency loop from block signature → coinbase txid → merkle root → block header → block signature.
  • The nonce field is set to 0. This avoids having to recalculate the signature for every attempt at finding a block hash to match the target difficulty. However it does lead to some malleability in that a user without mine permissions could generate a block with the same content as a valid block, but with a different nonce. Seeing as the nonce serves no purpose other than to randomize the block’s content for its hash, this should not be a source of concern.

In the case of a permissioned MultiChain blockchain, consensus is based on block signatures and a customizable round-robin consensus scheme, rather than proof-of-work as in bitcoin.

On the first server, run:

grant 15ZLxwAQU4XFrLVs2hwQz1NXW9DmudRMcyx2ZV mine

(Even though the permission is called mine note that there is no real “mining” taking place, in the sense of proof-of-work.) On the second server, check that two permitted block validators are listed:

listpermissions mine

Run this on both servers to maximize the degree of validator randomness:

setruntimeparam miningturnover 1

Now wait for a couple of minutes, so that a few blocks are added. (This assumes you left the block time on the default of 15 seconds.) On either server, check the creators of the last few blocks:

listblocks -10

The address of the validator of each block is in the miner field of each element of the response.

Snippet:
RR Mining

Node-1 Terminal | Node-2 Terminal

 

Reference: https://www.multichain.com/developers/mining-block-signatures/
https://www.multichain.com/getting-started/