> For the complete documentation index, see [llms.txt](https://docs.extrachain.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.extrachain.io/exconsensus/block-merge-algorithm-bma.md).

# Block Merge Algorithm (BMA)

Block Merge Algorithm (BMA):

If BMA is started, then one or more blocks in local blockchain can be corrupted or incomplete. Also, new block can have malicious data. Thus, approver must make deep scan of block data.

1. Compare received and old block data.
   1. If data hash is different – compare block data and detect new transactions.
   2. If there are no new transactions:
      1. And previous block hash is same – drop received block.
      2. And previous block hash is different – stop BMA and start BPA;
2. Check detected transactions with TVA. If transactions pass TVA, new block with added transactions is produced and distributed.

New block can trigger chain of BMA calls to make consistent chain for each network unit.

![Block Merge Example](/files/-Ma2xc7WOikNlM4KY16p)

![BMA Scheme](/files/-Ma2xraxqUsuDC9e000K)


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