Delayed Proof of Work (dPoW) is a security mechanism designed by the Komodo project. dPoW is basically a modified version of the Proof of Work (PoW) algorithm, which uses Bitcoin's hashpower as a way to improve network security. Using dPoW, Komodo project developers are able to secure not only their own blockchain network, but also any third-party networks that join the Komodo ecosystem in the future. In reality, dPoW can be implemented in any project that develops an independent blockchain, as long as it is based on the UTXO model.


How does dPoW work?

Taking the Komodo case as an example, the dPoW security mechanism was developed and implemented in the Zcash base code, which enabled the use of zero-knowledge proofs for greater privacy, in addition to improving network security. through Bitcoin hashrate.

At ten-minute intervals, the Komodo system takes a snapshot of its own blockchain. The snapshot is then written to a block on the Bitcoin network through a process called notarization. Basically, this process creates a backup of the entire Komodo system, which is recorded on the Bitcoin blockchain.

In more technical terms, the Komodo community chooses the nodes that will carry out this notarization process. These nodes are called notary nodes and are responsible for recording the block hash of each dPoW network on the Komodo blockchain. For each notarization record, a transaction is made on the Komodo blockchain. Using the OP_RETURN command, notarization nodes record a single block hash on the Komodo chain.

Notary nodes select a block hash that was created about ten minutes ago. This ensures that the entire network complies with block validity. Still, each blockchain network needs to reach consensus regarding each block. Notary nodes only record the block hash of a block that has already been mined previously.

The notarization nodes then record a block hash from the Komodo network on the Bitcoin network. Similarly, the process also depends on a BTC transaction, using the OP_RETURN command to write the data to a block on the Bitcoin blockchain.

Once the notarization process on the Bitcoin network is completed, Komodo notary nodes record the information from that same block on the Bitcoin network back to each of the other blockchains that have implemented the dPoW mechanism. At this point, the network will no longer accept any type of change to the notarized block (or any other block that was created before the most recent notarized block).

Currently, the dPoW mechanism makes use of the Bitcoin network, but it can be used as a tool to take advantage of the security or functionalities of any other blockchain that makes use of a UTXO model.


PoW vs dPoW

One of the main objectives of the Proof of Work (PoW) algorithm is to maintain network security, preventing attacks - such as DDoS (Distributed Denial-of-Service) attacks. In a nutshell, the PoW algorithm is a set of data that is very expensive and difficult to produce but can be easily verified and this is a crucial element of the mining process.

Mining blockchains using PoW was intentionally designed to be very demanding and costly. Miners need to solve a fairly complete cryptographic puzzle in order to mine a new block. This process involves very intense computational work, which demands a lot of resources in terms of hardware and electricity. Mining not only protects the network against attacks, but also verifies the legitimacy of transactions and generates new units of cryptocurrencies (as a reward for the miner who solved the puzzle).

Therefore, one of the reasons Proof of Work blockchains are secure is the fact that the mining process requires a very high investment of financial resources, in addition to being dependent on network consensus. However, it is important to remember that the security of PoW blockchains is directly related to the amount of computing power (hash rate) dedicated to them. This means that a small blockchain network is not as secure as a large one.

Unlike PoW, dPoW is not used to reach consensus on new blocks and is therefore not considered a consensus algorithm. Instead, dPoW is a security mechanism that is implemented on top of the consensus rules of a PoW algorithm - as if it were an extra layer of protection. The dPoW mechanism makes it impossible to change or reorganize blocks that have been notarized, which means that blockchains can become even more secure and resistant to 51% attacks.

Technically, dPoW “resets” a blockchain’s consensus rules whenever a new block is notarized. For example, most PoW networks are based on the “longest chain” rule. So every time a blockchain network receives confirmation that block XXX,XX1 has been notarized, the longest chain rule is reset on block XXX,XX2. The system will not accept a chain that starts with block XXX,XX0 or earlier, even if that chain is the longest.


Final considerations

The delayed Proof of Work security mechanism allows backups to be performed frequently to ensure that in the event of a system failure or attack, all data can be quickly recovered. For a hacker to be able to cause irreparable damage, he would have to take down the Bitcoin network as well, destroying all snapshots that were recorded on the Bitcoin blockchain.

For those who want to learn more about the dPoW mechanism, please check out the Komodo project's Blockchain Security Services page.