What Is Delayed Proof of Work (dPoW)?
Delayed Proof of Work is a security solution that enhances network security by utilizing the Bitcoin blockchain's hashpower. It creates frequent backups of the system to ensure a secure and reliable network. It's meaningful because it allows independent blockchains of any project to implement dPoW for their network security, which is particularly important in the event of a system failure or successful hack.
Basics
Delayed Proof of Work (dPoW) created by the Komodo project is a security solution that modifies the Proof of Work (PoW) consensus algorithm by utilizing the Bitcoin blockchain's hashpower for network security enhancement. Through dPoW, not only does Komodo secure its network, but it also provides security for any third-party chains that may eventually join the Komodo ecosystem. The UTXO model-based independent blockchains of any project can implement dPoW for their network security.
Explaining the Mechanism of dPoW
The dPoW security mechanism was designed by the Komodo project to increase network security by utilizing Bitcoin’s hash rate. One example of its implementation is in the Zcash code base, which allows for zero-knowledge privacy. So how does dPoW work in Komodo's system?
Every ten minutes, a snapshot of the Komodo blockchain is taken and notarized by writing it into a block on the Bitcoin network. This snapshot serves as a backup for the entire Komodo system, saved within the Bitcoin blockchain. The notary nodes, which are elected by Komodo's community, write a block hash from every dPoW-protected blockchain onto the Komodo ledger using the OP_RETURN command.
The notary nodes select a block hash that is approximately ten minutes old to ensure the network agrees the block is valid. The notary nodes write a block hash from the Komodo chain onto the Bitcoin ledger by executing a BTC transaction and using OP_RETURN to write the data into a block on the Bitcoin chain.
After notarization to Bitcoin, Komodo's notary nodes write that block data from the BTC chain back onto the chain of every other protected chain. This ensures that the network will not accept any re-organizations that attempt to change a notarized block or any blocks created before the most recently-notarized block.
Currently, dPoW is being used with Bitcoin, but it has the potential to be applied to other blockchains that use a UTXO model, allowing them to leverage its security and features.
PoW vs dPoW
The Proof of Work algorithm is designed to ensure network security by deterring cyber attacks like Distributed Denial-of-Service attacks (DDoS). The algorithm involves solving a complex cryptographic puzzle that is costly in terms of hardware and electricity but easy to verify. The process of mining not only protects the network from external attacks but also verifies the legitimacy of transactions and generates new cryptocurrency units.
The security of PoW blockchains is directly related to the amount of computational power (hash rate) being devoted to them. However, small blockchain networks are less secure than large ones. In contrast to PoW, dPoW is not a consensus algorithm but a security mechanism implemented in addition to ordinary PoW consensus rules. It makes it impossible for notarized blocks to be reorganized, which increases the security and resistance of blockchains to 51% attacks.
dPoW "re-sets" a blockchain's consensus rules every time a block is notarized. For example, most PoW chains use the "longest chain rule," so each time a blockchain's network receives confirmation that block XXX,XX1 has been notarized, the longest chain rule starts over at block XXX,XX2. The network will not accept a chain that begins at block XXX,XX0, or prior, even if it is the longest one.
Conclusion
To ensure a secure and reliable network, the delayed Proof of Work security mechanism creates frequent backups of the system. This is particularly important in the event of a system failure or successful hack, as the entire data can be quickly recovered. In order for an attacker to cause lasting damage, they would have to take down the Bitcoin network, which would also destroy all of the snapshots backed up within the Bitcoin blockchain.