POW is one of the most mainstream consensus mechanisms, and it is also the cornerstone of cryptocurrency mining industry. In recent years, frequent security incidents and 51% attacks have made POW attacked by many industry experts. Vitalik, founder of Ethereum, also tweeted: “I think this shows the importance of POS in the long run. I hope that after we switch to POS, 51% attacks will no longer appear even on the smallest chain. ”
But is pos really better than POW?
First of all, let’s look at pow. Bitcoin uses POW mechanism. Adopting such a consensus mechanism means that mining machines need to use SHA-256 to calculate when they are digging new blocks. If an attacker wants to modify information, he must complete all the work of the block plus the previous block, and then catch up with and surpass the work of honest nodes, that is 51% attack.
POS determines the bookkeeping right by calculating your percentage of the total amount of currency and the length of time. Compared with pow, POS reduces the waste of computing power and the possibility of being attacked. However, the disadvantages of POS are also obvious: first of all, mining can not be completely avoided for the major cryptocurrencies with the largest market value at present. Even if it is converted into POS, mining is a necessary process, which cannot be skipped or omitted. With the passage of time, the growth of the weight of early holders in POS will inevitably lead to centralization. At that time, decentralization will be replaced by some nodes with too high weight, and the security can not be guaranteed.
Is there any other consensus algorithm that can solve the disadvantages of these two mainstream algorithms? Therefore, a new blockchain system bit ecological digital asset (bed) emerges as the times require.
The hybrid consensus algorithm mechanism of pow + POS is adopted in bed. The pow consensus component of bed is similar to bitcoin and uses hash-256 hash function. The pow miner of bed is responsible for proposing new blocks to the blockchain, but the effectiveness of the blocks must be verified by the POS consensus node before the new blocks can be added to the blockchain network.
Its operation principle is as follows:
When the pow miners of bed find a valid block, they will broadcast on the network. In order to make the block be considered valid, the block must be verified by most POS holders, that is, each block must be approved by 3 / 4 of the holders.
Specifically, in the POS mechanism of bed, 1008 blocks are a cycle (about 7 days), corresponding to 1008 tickets and 1008 ticket holders. The tickets currently purchased can only take effect in the next block. In each block time, 1008 ticket holders are assigned to 21 voting groups (48 votes for each voting group) based on random function. Each group votes to elect the representative of the group, and 21 representatives will vote on the validity of the block submitted by POW miners. If the block is approved by 3 / 4 representatives, the block will be added to the main network as an effective block.
In each voting group, the representative must be approved by 3 / 4 of the members. If the group fails to elect the representative within the specified time, it cannot participate in the block voting. At the same time, in order to prevent POW miners and POS ticket holders from conspiring to attack the main network, all tickets will be encrypted and grouped to hide the identity of the ticket holders (but the corresponding identity relationship will be encrypted in the network), and all the selected representatives will also be encrypted.
In this way, in bet’s POS consensus algorithm, the ticket holder represents the interests of most token holders in the whole network, and there is a cooperative interest relationship between the pow miner and the POS ticket holder. When the block submitted by the pow miner is valid, the miner and the ticket holder share the mining income and block reward; When a POW miner submits an invalid block, the POS holder must honestly identify it as invalid. Otherwise, as the ticket holder, they will bear the greatest loss. At the same time, the pow miner will not be able to obtain income, wasting time and computing resources. Therefore, only through honest cooperation can POW miners and POS obtain the maximum economic benefits.
The POS ticket holders and POW miners of bed not only operate independently, but also restrain each other, and jointly maintain the ecological balance of bed, so as to solve the problems mentioned above. In addition, bed supports all bitcoin mining machines. Now that the cost of bitcoin mining is too expensive, bitcoin miners turn to be able to get good returns by digging bed.