---
title: "Trust Boundary"
path: "/contents/tech/core-concepts/trust-boundary"
version: "1.1.1"
author: "Hydrate"
createdAt: "2026-02-03T14:24:24.378Z"
updatedAt: "2026-07-20T21:40:54.663Z"
---

# Trust Boundary

<Infobox>
| **Field** | Distributed systems · security architecture |
| **Definition** | The line beyond which a component must rely on another’s integrity |
| **Forms** | Physical (firewall, auth) or logical (module / privilege interface) |
| **In blockchain** | Each ledger is its own trust boundary; cross-chain transfers require bridges |
| **Radix approach** | Linear scaling via braided sharding keeps the whole network inside one trust boundary — atomic cross-shard composability, no bridges |


</Infobox>

**A Trust Boundary** [ /trʌst ˈbaʊndəri/ ] is a concept used in distributed systems to describe the point beyond which a component must rely on the behavior and integrity of another. Trust boundaries are important because they define the limits of a system's security and control.

## Overview

In the context of blockchains and distributed ledgers, trust boundaries are the reason why assets cannot be transferred between different chains and instead require workarounds such as [burn and mint bridges](https://docs.chainswap.com/mechanism/chainswap-architecture).

Radix has its own trust boundary and is designed to obviate the need for asset swaps or sidechains by being linearly scalable.

## Trust Boundaries in Distributed Systems

In the context of distributed systems, a trust boundary can take the form of a physical boundary, such as a network firewall or user authentication system. It could also be a logical boundary, such as an interface between two separate software components or a boundary between different levels of privilege within a system.

Regardless of its form, a trust boundary serves as a dividing line between different parts of a distributed system. On one side of the boundary, the system can be trusted to behave as expected and to enforce security controls. On the other side, the system's behavior is less certain and may be subject to malicious or unintended actions.

One of the key challenges of managing trust boundaries in distributed systems is ensuring that they are properly enforced. This can be difficult because distributed systems are often composed of many different components that may be developed and maintained by different teams or organizations. As a result, it can be difficult to ensure that all components are properly configured and secure, and that they all adhere to the same security standards.

To address this challenge, many organizations rely on strict security policies and procedures, as well as security tools and technologies, to enforce trust boundaries and protect their distributed systems. This can include things like encryption, authentication, and access controls, as well as regular security assessments and vulnerability testing.

Overall, trust boundaries are an important concept in the field of distributed systems. They help to define the limits of a system's security and control, and determine which parts of a system can be trusted to behave as expected. By properly enforcing trust boundaries, organizations can help to protect their distributed systems from security threats and ensure their reliability and integrity.

## Radix and the single-ledger trust boundary

Most blockchains scale by adding ledgers — sidechains, rollups, or app-chains — and every new ledger draws a fresh trust boundary. Moving an asset across one means trusting a [burn-and-mint bridge](https://docs.chainswap.com/mechanism/chainswap-architecture) or a wrapped representation, which is why bridges have been among the most exploited components in crypto.

Radix takes the opposite route. Its [Cerberus](/contents/tech/research/cerberus-whitepaper) consensus [shards](/contents/tech/core-concepts/sharding) the ledger into many parallel [shard groups](/contents/tech/core-concepts/shard-groups) while braiding them together for any transaction that touches more than one, so a single transaction can atomically span shards. The result is a network that scales throughput without ever splitting into separate trust boundaries: [atomic composability](/contents/tech/core-concepts/atomic-composability) holds across the entire ledger, and no bridge is needed to move value within it.