A note on Simple Bridge security, operations, and future plans. First of all, we would like to thank the community and other ecosystem participants for actively using Simple Bridge and the related InSwap product. This note is not a response to any security incident. Simple Bridge has been operating normally, and there has been no security incident affecting user assets since launch. We are sharing this note because we believe it is useful to make the bridge’s design, operational assumptions, and future direction easier for users and communities to understand. Recently, the community raised questions regarding Simple Bridge, especially around the security of bridged assets and the following Bitcoin address: `bc1ps0qa22q30rrp4584gz4teqkchn76wakzaq6mlhsv6sg36e0fl83sss2vxa` We appreciate these questions. For new users, it is not enough to rely on reputation alone. A bridge should be understandable, its core assumptions should be clear, and its on-chain records should be auditable. Why it is called Simple Bridge Simple Bridge is a traditional bridge that applies a classic distributed multi-signature mechanism for asset security. It intentionally avoids overly complex or experimental designs. Instead, it uses a relatively simple and time-tested security model: assets are managed collectively by multiple validator nodes under a distributed multi-sig architecture. This is the reason behind the name “Simple Bridge.” The goal is not to make the system look sophisticated. The goal is to make the security model clear, operationally stable, and easier to reason about. Key security and operational properties 1. Distributed multi-sig custody Simple Bridge secures bridged assets through a multi-signature system distributed across validator nodes. Asset movement requires coordinated validation rather than unilateral control by a single party. 2. Distributed service architecture The bridge service is designed with a distributed architecture, exposing only necessary service nodes and reducing unnecessary attack surfaces. This helps improve robustness and operational stability. 3. Auditable on-chain records Deposits and withdrawals are recorded on-chain and can be independently reconciled. This is an essential property of any bridge service and an area we will continue to improve. Operational history Since the launch of Fractal, Simple Bridge has been actively maintained by UniSat for more than 1.5 years. During this period, the bridge has remained in stable operation, with zero security incidents affecting user assets. This does not mean any system should be treated as risk-free. It means that the current architecture, operational process, and maintenance model have been tested in real production usage over an extended period of time. About the referenced address The address below is one of the core business addresses used by Simple Bridge: `bc1ps0qa22q30rrp4584gz4teqkchn76wakzaq6mlhsv6sg36e0fl83sss2vxa` This address is protected under Simple Bridge’s distributed multi-sig security architecture. It is also expected to remain unchanged in future operations, unless there is a major upgrade or migration that is publicly announced in advance. Integration with InSwap In 2025, we integrated Simple Bridge into InSwap to simplify the user experience. The purpose was to reduce the number of manual steps users needed to take, shorten waiting time, and make the bridging process more natural for normal asset swap flows. This integration did not change the core security model of Simple Bridge. It was mainly a product-level improvement designed to reduce user friction. From one-way bridge to two-way bridge Historically, Simple Bridge has mainly supported one-way bridging from Bitcoin to Fractal. This allowed assets on Bitcoin mainnet to move to Fractal in a relatively simple BRC-20 format, helping users access lower-cost transactions and more flexible application scenarios on Fractal. The next step is to expand Simple Bridge into a two-way bridge: Bitcoin <-> Fractal This will allow assets on Fractal to move back to Bitcoin mainnet in a relatively simple form. This is important for the broader Fractal ecosystem. It will also make it easier for the upcoming UniHexa to support FB and other Fractal-based assets directly on Bitcoin mainnet. Support for more asset protocols From a functional perspective, we will continue extending Simple Bridge to support more asset protocols, including Runes. The broader goal is to improve asset mobility between Bitcoin and Fractal, while reducing unnecessary on-chain transaction costs for users and applications. Improving auditability We also plan to further improve the auditability of Simple Bridge. Users should be able to more easily review deposits, withdrawals, bridge response status, and fund movements. Our goal is to make it convenient for anyone to verify bridge activity through UniScan at any time. Closing note Simple Bridge is designed as a practical bridge with a clear security model, distributed multi-sig custody, auditable on-chain records, and long-term maintenance by UniSat. We appreciate the community and all ecosystem participants who help make these questions explicit. For infrastructure used by real users, clear communication and continuous auditability are part of the work. We will keep improving Simple Bridge in that direction. Lorenzo 2026.05