Notary Nodes on Komodo Network. Protection from attacks.
When Satoshi Nakamoto launched the Bitcoin network in 2009, he included a message from the Times newspaper into the first block of the Bitcoin’s blockchain in a similar way to how Komodo network includes its backup numbers into Bitcoin transactions.
To include his message, Nakamoto used a function called Coinbase. Komodo uses “OP_Return.” The main difference between the two functions is that the former is available to miners and the latter is available to all users engaging in transactions on the Bitcoin network.
The most important conclusion here is that just like the message by Nakamoto is viewable by all and available to all (you can see it by visiting Bitcoin Blockchain explorer and looking at block #1, the Genesis block, here: https://blockchain.info/block/00000000839a8e6886ab5951d76f411475428afc90947ee320161bbf18eb6048), so are the backups of the Komodo network.
The fact that the Komodo network stores its backups on the Bitcoin blockchain means that in case of a devastating event, the network could use the Bitcoin blockchain to rebuild itself and there could be no argument about which Komodo blockchain is the original one.
The final step of the notarization process on the Komodo network is making a record about where the network has stored a backup. The network makes these records on its own blockchain. This serves as a way to let the users on the network know where to look for backups in case an incident occurs. The Komodo network does it by combining the information about the first step of notarization (in which it combined the height of the block with the name of the network and the hash) with the information about the transaction on the bitcoin network. The result, again, is a long computer-friendly number, such as 234234fg23k32s22W86b. Just as all other similar numbers on the Komodo network, this number is created with the help of a cryptography algorithm. Because this number is linked to all the other numbers, changing even one digit in the information about transactions on the Komodo network that have occurred prior to the creation of this number would result in the mismatch of the data. As the last part of the process, this last number becomes a part of the Komodo network itself, fundamentally interlinking the network with the Bitcoin network for added security.
Benefits that notary nodes get on the Komodo network
Notary nodes on the Komodo network don’t just perform additional work. As a reward for doing the work, they get a privilege that incentivizes them to keep doing the notary work on the network. Each notary node on the Komodo network periodically gets a chance to create an easy block. Once the notary node uses this opportunity, the opportunity becomes unavailable to this particular node for the next 64 blocks. After the 64 subsequent blocks, the notary node can again try and get an opportunity to mine an easy block on the Komodo network.
This means that while all other miners on the network are compiling transactions into blocks according to the network-wide difficulty level that works in the same way as on the Bitcoin network, the notary nodes get a chance to play by much easier rules. Practically speaking, this means that a chance that a block out of every 64 blocks on the Komodo blockchain has been created by a notary node and not a regular miner is 75 to 25. This will not change if more miners join the Komodo network as there will always be 64 elected notaries and the rules for notary nodes will be different than the rules for regular miners.
The software code behind the dPoW allows the network to elect the notary nodes based on proof-of-stake algorithm with voters on the platform getting stake-weighted vote according to how much KMD they own.
At the same time, the Komodo network removes the ability to create easy blocks from the notary miners every 2000 blocks and does so for 64 blocks. When this happens, all miners on the network play by the same rules. This means that while notary nodes do play a very important role on the Komodo network, at the same time they do not control the history entirely and at times the entire Komodo ecosystem takes over the elected few.
Defense of the Komodo network against the 51% attack and the Genesis Attack
The 51% attack is when an attacker or a group of attackers gain control over 51% of the block-creating nodes on a blockchain. In Komodo’s case, for someone to successfully perform a 51% attack would mean that the attacker would have to take over the majority of the elected notary nodes and then be able to control over 51% of the entire network during the period when the notary nodes don’t get the privilege of creating easy blocks.
If a hacker were to take control over the elected nodes, in the best-case scenario the hacker would be able to prevent the backups going forward, but not do anything to the existing blocks of the Komodo blockchain.
Because of this, 51% attack is even less possible on the Komodo blockchain than it is on the Bitcoin blockchain.
Another potential attacking method that hackers could use to take control over a blockchain network is the Genesis Attack. During the Genesis Attack, attackers recreate the Genesis Block of a blockchain and create a blockchain that is longer than the original chain. If the network uses a proof-of-work algorithm to reach consensus, it will most likely accept the longer chain as the true one and get rid of the original blockchain deeming it a false copy. With the Komodo network, this attack is simply not possible because the Komodo network doesn’t even compare the chains. It restores backups using another blockchain and the information it stores in its own blockchain.
If an attacker were to try and create a modified copy of the Komodo blockchain starting with the first block, the network would simply ignore the newly modified blockchain as if the new blockchain didn’t exist. These security features do not just apply to the Komodo network itself. They also apply to all the asset chains that developers may build on the Komodo network. This way, the Komodo network provides its users with Bitcoin-level security and stability, yet does so at a tiny fraction of Bitcoin’s costs.