By: Mark Blackman,Senior Director of Product, Hashgraph

Every robust network relies on a registry of participants - whether it's DNS, routing tables, or MAC address tables. These registries are vital for enabling network participants to discover and connect seamlessly with each other. In decentralized or trustless environments, such registries must not only be reliable but also provable, secure, and capable of adapting to changes autonomously.

On the Hedera network, the Address Book acts as this registry, storing critical information such as:

• Nodes participating in network gossip and consensus
• Endpoints for SDK transactions
• Consensus weight values derived from stake delegation

The Address Book is currently managed by the Hedera Governing Council, which oversees, approves, and signs all updates. While this centralized approach has been effective in maintaining the network's integrity, Hedera's commitment to decentralization necessitates a more autonomous and flexible solution. Over time, this shift will empower node operators to manage their entries within the Address Book, fostering greater independence and scalability.

Enter the Dynamic Address Book, introduced in HIP-869. This transformative update simplifies Address Book management by enabling node operators to control their entries via transactions submitted to Hedera's mainnet. The result? Reduced manual oversight, automated updates, and a significant step toward permissionless network participation.

Manual to Automated Management
Currently, managing the Hedera Address Book requires action by the Hedera Governing Council. For instance, adding or removing a node involves the Council's approval, configuration, and a network restart - an approach that can become inefficient as the network scales.

The Dynamic Address Book optimizes this process by:

1. Introducing new API endpoints for automated updates
2. Leveraging Hedera transactions for transparent and verifiable Address Book changes
3. Reducing downtime by minimizing the need for network-wide resets

Implementation Timeline

The Dynamic Address Book will be delivered in two stages:

1. Stage 1 (Release 0.56): Introduces the HAPI endpoints to facilitate Address Book changes via signed transactions. The specifications or technical details in this blog are for Stage 1.
2. Stage 2: Implements full functionality, allowing daily Address Book updates aligned with the end of staking periods.

Dynamic Address Book: Key Features and Benefits

New HAPI Endpoints
The Dynamic Address Book introduces three key transaction types to manage nodes in the network.

Node Admin Key
To enable direct management, each node operator must use a Node Admin Key to sign transactions related to their node. This key ensures that only authorized changes are made and shifts responsibility to node operators to manage their entries.

The Impact of the Dynamic Address Book

The Dynamic Address Book is a pivotal step in Hedera's journey toward decentralization. It not only streamlines operations by reducing manual intervention but also lays the foundation for permissionless participation. This innovation empowers node operators with greater autonomy and transparency while also ensuring the registry remains secure, reliable, and verifiable.
As Hedera evolves, the Dynamic Address Book will play a critical role in fostering a decentralized and scalable ecosystem.

Learn More
To dive deeper into the Dynamic Address Book and its implementation, refer to HIP-869.