KDAG Foundation
2 min readSep 22, 2020


The core problem of the blockchain is to slove the problem of consistent evolution of distributed ledgers in a public network environment. We analyze from two issues:

1) Who will keep the books.

2) How non-bookkeepers verify that the bookkeeper is lying.

Take mature Bitcoin and Ethereum as examples, that is, the pow consensus algorithm, which uses the hashing power to compete for bookkeeping rights. The Merkle Tree or Merkle Patricia tree is used as the basic data structure of the ledger to make “non-bookkeepers” fast Verifying that the bookkeepers have lied, and the introduction of a punishment mechanism (Payment of computing power), so that the bookkeepers have no incentive to account for bad debts from an economic perspective, and eventually make Bitcoin and Ethereum become the digital currency field. Successful practitioner of blockchain technology.

We know that there are three important data in a block header of Ethereum. They are the hash of the Merkle tree root node, including: state tree, transaction tree, and receipt tree. In the Ethereum network, the historical data of the world ledger on a node is proved by hashing power, so it is credible. When a miner successfully records a batch of accounts (so-called mining), it pays Computing power. After broadcasting, other nodes will verify whether the account is correct by the miners based on the local trusted ledger data. The core process is:

A. Based on your own local ledger (of course, you must strive to keep the local ledger to be the current longest chain, which is not described in detail here), the transactions in the block are executed in order. Then change the state of the local world ledger, as well as the receipt tree, etc., to form a new world state root hash and a receipt tree root hash.

B. Compare the local new world state with the result given by the bookkeeper. That is, the comparison of the three merkle root hashes. Consistent, then it is recognized that the bookkeeper has not lied, and the local ledger and the bookkeeper’s ledger will continue to evolve in unison.

In this way, as the network has to be generated one by one, every ledger in the world has maintained a consistent evolution.