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Quick Facts

• The Logos Blockchain is a blockchain infrastructure that functions as the foundational layer of the Logos technology stack.
• It is designed to host decentralised applications and institutions requiring high levels of privacy and resilience.
• The network is designed with low entry barriers, allowing nodes to participate with typical consumer hardware and any amount of stake.
• Logos Blockchain consists of two layers: lightweight, permissionless blockchains called Zones built on top of a Layer 1 foundation called Bedrock. The Blend Network service is used to improve the privacy of the network. </aside>

Introduction

The Logos Blockchain is a blockchain infrastructure designed for decentralised applications for social institutions that require high levels of privacy and resilience. It facilitates the creation and operation of these applications, provides a common context for their interaction, and gives users the ability to freely use any application they desire. Despite the diverse variety of apps that can be built on Logos, it provides guarantees that they will operate correctly, securely, and without corruption.

The Logos Blockchain was designed with the following principles in mind:

• Privacy: The Logos Blockchain must protect information associated with all participants, regardless of their involvement in the network. On the infrastructure level, Logos nodes must be confident that their block proposals have a very low probability of being traced. Logos also provides developers with the tools to build applications with programmable privacy, allowing these applications to keep personal data hidden.
• Neutrality: Activity on the Logos Blockchain must be handled in a way that does not compromise the public neutrality of Logos nodes. This way, nodes can participate in processing transactions without having to make their inclusion public.
• Resilience: The Logos Blockchain must remain operational and protect privacy in the face of complex geopolitical scenarios, surviving challenges like a partitioned internet, heavy censorship, and hostile government action. To attract nodes and reduce points of failure, running a Logos node even on a laptop must be easy and straightforward. Scaling to accommodate as many nodes as possible is best accomplished with a consensus protocol that prioritises liveness, resulting in a network that continues operating even in the worst of conditions.

Architecture Overview

The Logos Blockchain is implemented as two blockchain layers. Application execution takes place on lightweight, permissionless blockchains known as Zones, which are built on top of a solid Layer 1 foundation known as Bedrock. The privacy properties of Bedrock are extended by the Blend Network service.

Bedrock

Bedrock is a large-scale validator network that serves as the foundational layer of the Logos Blockchain, providing consensus, data availability, and lightweight verification to Logos Zones. Its Private Proof of Stake (PPoS) consensus protocol (known as Cryptarchia) ensures block proposers retain their privacy, while remaining scalable, resilient, and accessible. Bedrock also enables decentralised sequencing for Zones, and allows for token bridging and inter-Zone messaging.

Serving as a Bedrock validator node is as simple as having the Logos node application run in the background on a laptop, with a “set it and forget it” approach to maintenance. This design makes it easy to contribute to the security, consensus, and interoperability of the Logos Blockchain.

Blend Network

While Bedrock provides the core functionality, network-level privacy for consensus is ensured by an opt-in service known as the Blend Network. The Blend Network enhances Logos’ privacy guarantees by virtually eliminating the likelihood of linking the proposer of a block to the block they propose - thereby ensuring they cannot be targeted. Node operators who choose to participate in the Blend Network are expected to have increased hardware requirements compared to the minimal ones necessary for Bedrock validation.

Zones

Applications on Logos do not run directly on Bedrock. Instead, they are implemented on Layer 2 blockchains known as Zones. These Zones define their state transitions and validity independently of Bedrock, but rely on the Layer 1 for consensus guarantees. This modular design provides freedom and customisability in creating a chain, allowing creators to maximise properties like performance.

While Zones can be implemented as truly independent sovereign rollups, Bedrock also enables token bridging and decentralised Zone sequencing. Zones can also choose to communicate between each other by exchanging asynchronous messages via Bedrock. These features allow for limited interoperability without significantly compromising the advantages of the sovereign rollup model.

The most important example of a Zone is the Logos Execution Zone. The Logos Execution Zone is the initial host for the messaging and storage applications of the Logos stack, with support for private token transfers and program execution.