A node in blockchain technology refers to any computing device (such as a computer, laptop, or server) that participates in the blockchain network. These devices are responsible for maintaining a copy of the distributed ledger, which is a decentralized and immutable record of all transactions across the network. Nodes contribute to the network’s functionality by validating and relaying transactions, participating in the consensus process to agree on the state of the ledger, and ensuring the integrity and security of the blockchain.

Node Registration Simplified:

In our network, while anyone can run a node and join the network, only a select group of nodes has reached the highest score in the round can create blocks and receive Savi Coin. The process for a node to become registered or to be removed from the registry is governed entirely by the network’s rules, without any single user or authority having control over these decisions. This approach is designed with three main goals in mind:

• Enhancing Security: To safeguard against the theft of private keys and to prevent attackers from compromising the network by taking control of a majority of nodes.
• Maintaining Network Integrity: To ensure that only productive nodes, or those not exploiting the network in unforeseen ways, remain active and eligible for rewards.
• Regulating Node Participation: To manage how new nodes join the network and to remove inactive or non-contributing nodes efficiently.
  Here’s how we address each goal:
• Separating Private Keys: Unlike systems where block creation requires the node operator’s private key to be on the node itself, potentially exposing it to theft or attack, we keep the private key separate from the block creation process. This minimizes the risk of key theft from online nodes, especially those hosted on virtual private servers (VPS), where data center operators might otherwise access the keys.
• Controlling Node Registration: To prevent an attacker from overwhelming the network by registering a multitude of nodes simultaneously, our protocol limits the number of new nodes that can join the registry within a certain period. This control helps to prevent a single entity from gaining a majority control of the network.
• Removing Inactive Nodes: Through a scoring system, our Proof of Unity algorithm identifies and removes nodes that are offline or not actively participating. Nodes with a zero score are automatically ejected from the registry but can rejoin once they become active again.

This framework not only ensures the network’s security and efficiency but also plays a critical role in distributing coinbase rewards fairly. By incentivizing nodes to stay active and participate, we maintain a robust and reliable network. The specifics of how this scoring system works and its impact on rewards are further explained in the section on Proof of Unity.

Ultimately, by establishing a trusted federation of active nodes, we lay the groundwork for our platform’s future development, including faster consensus algorithms and advanced DApp functionalities in upcoming versions.

The Node Registry Life Cycle Simplified

After setting up a node and syncing it with the network, an owner can apply for inclusion in the node registry by submitting a registration transaction. This transaction provides details about the node and proof of ownership over the node’s private key. Once submitted, the node joins a registration queue awaiting available slots in the registry, as governed by the network’s rules.

Joining the Registry

A node must first demonstrate active network participation before it’s officially registered and allowed to create blocks. If a node doesn’t participate within 30 days in the queue, its deposit is refunded, and it’s removed from the queue. To reattempt registration, the node owner must submit a new registration transaction and pay the fee again.

Active Registry Participation

Registered nodes are assessed by the Proof of Unity algorithm, which adjusts their participation score based on network activity and other parameters. This score influences their share of participation rewards. Nodes can update their registration details or increase their deposit to improve their registry standing through update transactions.

Key and Fund Management

If a node owner loses access to her account’s private key but still controls the node’s private key, she can transfer the node’s deposit to a new account via a claim node transaction. This action, however, removes the node from the registry. It’s crucial for node owners to secure their nodes, as compromised nodes risk losing their deposits.

Owners can voluntarily remove their nodes from the registry to reclaim their deposits through a remove node transaction, which forfeits the node’s participation score and its place in the registry.

Automatic Ejection and Re-Queueing

Nodes with a participation score that falls to zero are automatically ejected from the registry but can rejoin the queue after to paid the tax, provided they become active again.

Kicked out

At Proof of Unity, we’re all about being open and trusting each other in the network. If any node in the network tries to cheat, attack the network, give itself the highest score, or block others, it will be kicked out. The coins it put down as a pledge when joining will be taken away and given to the honest members in the next rounds.

Registry Structure

Savitri’s network maintains a node registry that links user accounts to their operated nodes, enabling secure block signing and direct rewards for node participation without exposing private keys.

This streamlined overview simplifies the node registry lifecycle in the Savitri network, focusing on registration, participation, and management procedures while ensuring network security and efficiency.
Each node’s entry in the registry declares the following properties:

Field	Description
Public Key	The public key corresponds to the node’s configured private key. When blocks or Proof of Unity messages are produced by a node, the signatures can be validated against this key.
Account Address	The account address of the node owner’s account. This account may legally change or remove the node registration, and any participation rewards earned by the node are credited to this account.
Locked Balance	An amount of funds that the node’s owner has put up as collateral to compete for a spot in the registry, and to incentivize her to maintain the security of her node’s private key.
Participation Score	A score tracked for this node over time by the Proof of Unity algorithm. A higher score increases the number of rewards received, while falling to zero will cause the node to be ejected from the registry.

The Node’s Public Key and Security

Each node in the Savitri network maintains a private key to sign blocks, ensuring transactions and messages are authentically from the node. This private key, ideally stored securely on the node’s device, can also be managed through a separate hardware device for enhanced security. This measure is crucial because if a node’s private key is compromised, it risks impersonation and potential loss of locked funds by attackers.

Locked Balance for Registry Maintenance

To be part of the registry, a node owner locks a certain amount of Savitri tokens. These funds are deducted from the owner’s account and held by the network as a security deposit. If a node is removed or voluntarily exits the registry, these funds are fully returned. The size of the locked balance plays a role in prioritizing the node’s position in the registration queue, serving as a deterrent against Sybil attacks without relying solely on Proof of Stake principles.

The Registration Queue

Nodes awaiting registry entry are placed in a registration queue, ordered by the amount of their locked funds. Admissions from the queue to the registry occur at regular intervals, with the pace adjusted based on the registry’s size to maintain network security.

Registering a Node

Registration involves submitting a transaction with the node’s public key, a proof of ownership (a special message signed by the node’s private key), and the locked fund amount. This transaction, higher in fee to prevent abuse, locks the specified funds and adds the node to the queue.

Claiming a Node

In case a node’s private key is lost or compromised, the node can be claimed to recover locked funds, though this action removes the node from the registry. This mechanism aims to balance security concerns, ensuring that while nodes are safeguarded against unauthorized control, owners are incentivized to maintain strict security practices.

Ejection and Re-Entry

Nodes may be ejected from the registry if they become inactive but can re-enter the queue without additional fees, provided they re-establish activity. This process ensures that only actively participating nodes remain in the registry, supporting the network’s integrity.

Simplified Management with Savitri

Savitri simplifies this entire process, from registration to management and security of nodes, ensuring that participants can easily maintain their nodes with minimal technical expertise. Through the use of a user-friendly wallet application, node owners can effortlessly manage their registrations and secure their contributions to the network’s Proof of Unity, a novel approach replacing the traditional Proof of Participation to ensure a more unified and secure network operation.