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Light nodes remain in a state of active research at the time of writing.

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Quick Facts

• Light nodes verify consensus and data availability without storing full blockchain data, making them suitable for browsers and small devices.
• They can verify proofs for Zones they care about, enabling targeted state verification.
• Light node are designed to run on limited hardware like phones and browser wallets.
• Light nodes enable independent network integrity assessment, strengthening the security of Logos. </aside>

In decentralised networks, full nodes engage in consensus, but light nodes’ limited resources only allow for much more intermittent participation, suitable for browsers and small devices. To foster true decentralisation, light nodes require mechanisms enabling them to directly assess the network's integrity, without relying on third parties. By letting light nodes independently and affordably audit the system state, the Logos Blockchain gives them an equal seat in validating the network. The collective of light nodes is what allows the Logos Blockchain to be verified by large numbers of actors. This in turn helps realise the vision of open access and peer-to-peer cooperative dynamics between participants, regardless of their resources.

The idea of using a Light Node Network is integral for ensuring network scalability and user accessibility. Logos Light Nodes are designed to be run by the users of the network and capable of functioning on minimal-resource hardware. Light nodes perform the following tasks:

1. Consensus verification. Light nodes verify the consensus process engaged in by full Logos nodes. This is accomplished by downloading block headers and minimal block data, without actually participating in the mempool as a full node would. Following the network allows light nodes to make independent choices about the correct fork to follow.
2. Data Availability Sampling (DAS). An important function of these light nodes is independently verifying Zone data availability via LogosDA. Leveraging probabilistic methods, they can asses whether this data is available without needing to access the full data, a method that significantly reduces the workload for light nodes while maintaining network integrity.
3. Selective ZK proof verification. Light nodes can selectively verify Zone proofs on Bedrock relevant to their interests, such as from one or several Zones. This verification allows light nodes to engage in state verification in a selective manner, by verifying only the Zones they care about.

In addition to the above, Logos light nodes aim to provide strong security with minimal hardware requirements. Both Data Availability sampling and ZK proof verification processes are lightweight and are intended to be run from a phone, a browser wallet and potentially even more limited devices. Making verification so cheap strengthens the security of the network by the sheer number of entities collaboratively verifying the work of Logos nodes.

The network of light nodes ultimately helps protect the most important actors in the system: the users of Logos Zones. It is important to note that all these light node mechanisms are opt-in, altruistic and are not enforced by any cryptoeconomic incentives. Every light node, as a client of the network, is free to participate (or not) in altruistic data replication, and/or collaborating in collective action in the face of a massive disruption or misbehaviour on the Logos Blockchain.