OLA: Building the Trust-minimized Bridge core infrastructure for Bitcoin ecosystem

Reprinted from chaincatcher

03/30/2025·1M

Introduction to OLA

OLA is an infrastructure focused on cross-chain trusted interactions, providing inter-chain zero-knowledge proof for the Bitcoin ecosystem. Traditional BTC cross-chain bridges often rely on multi-signature custody or centralized intermediaries, which puts forward additional trust assumptions on user funds security, and funds are usually controlled by a single entity or a majority of entities. This model introduces concentrated risks, which deviates from the spirit of Bitcoin’s decentralization. In contrast, OLA aims to minimize the dependence of cross-chain bridges on third parties through cryptographic means and decentralized mechanisms.

With the gradual improvement of BitVM2 protocol engineering practice, Trust-minimized Bridge built on BitVM2 is an important infrastructure that various Bitcoin projects have begun to build. The construction of Bitcoin Trust-minimized Bridge requires several core basic modules:

Bitcoin Verifier script slicing
Target Chain Block Header ZKP
BitVM2 Challenger network of sufficient scale

OLA focuses on building a full-chain Block Header ZKP generation and management platform, providing verifiable chain state proof for each project's Trust-minimized Bridge, ensuring the credibility of state synchronization between different chains. The goal is to establish an interactive channel of the minimum trust assumption between Bitcoin and other blockchains, and realize a cross-chain bridge infrastructure without custodian participation. Through the chain state proof provided by OLA, a cross-chain bridge based on the BitVM2 protocol can verify state changes on the Bitcoin main chain and target chain without the need for a trust intermediary, thereby safely performing cross-chain operations such as Peg-In (anchor deposit) and Peg-Out (extraction and redemption). It is worth emphasizing that this design allows the cross-chain circulation of Bitcoin assets to no longer rely on centralized custody or federal multi-signature, but to ensure security with the help of zero-knowledge proof and decentralized verification network. OLA hopes to become a native cross-chain connection base for Bitcoin, extending Bitcoin’s security to multi-chain environments, and reducing the trust cost in cross-chain interactions.

OLA Technical Architecture and Module Description

The OLA system is composed of multiple modules in collaboration, each module performs its own functions, jointly realizing the generation, verification and submission of inter-chain state proofs. The main architectural modules include:

OLA Control HQ (Control Center) : Responsible for the management and orchestration of various modules of the entire OLA network, and is the core of task scheduling and external RPC services. Control HQ coordinates the proof generation, verification and submission process to ensure that each component works in sequence and provides interfaces to enable developers and other chains to call query chain proof services.
Myriad Chain Prover : Multi-chain proof generation module. This module generates proof of the validity of the block header hash for multiple blockchains through zero-knowledge proof technology (i.e., "chain proof"). It verifies that the blockchain header chains of each chain comply with consensus rules (such as the block hashing difficulty and link relationship of the proof of work chain) and outputs verifiable proof of validity. It should be noted that Myriad Chain Prover does not directly generate proof of inclusion of specific transactions, but focuses on the proof of consistency of the entire chain state. This design reduces the complexity of proof computing, focuses on providing trusted snapshots of various chain states, and provides basic trust for cross-chain interactions.
Onis : zkRollup with Bitcoin as the settlement layer, that is, OLA's zero-knowledge light client decentralized verification and zkp management module. As the trustless light node of each chain, Onis is responsible for receiving and storing the chain state proofs from Myriad Chain Prover and verifying the validity of these proofs on the chain. Onis essentially acts as a multi-chain verifier and the DA layer of chain proof: Through zero-knowledge proof technology, Onis can establish a secure connection between Bitcoin and other blockchains, realizing the seamless flow of assets and data between multiple chains. For cross-chain bridges, Onis plays the role of a target chain on-chain state verification contract. Once the new state of a chain is verified, its internal state root is updated, thereby maintaining the synchronization of multiple chain states. Since Onis uses Bitcoin as the settlement layer zkRollup, it maintains high efficiency while ensuring security and achieving both security and efficiency of cross-chain interaction.
DMN (Decentralized Massive Network) : Massive , a verification and supervision network composed of a large number of decentralized users , is the cornerstone of the OLA security model. DMNs contain multiple subnets or roles that jointly ensure the reliability of chain proof and cross-chain processes:
- MVN (Massive Verifier Network) : A huge node network responsible for independently verifying the chain proof submitted by Myriad Chain Prover. Any generated chain state zero-knowledge proof will be reviewed by a large number of verification nodes in the MVN to ensure the correctness of the proof. Onis' contract will only accept the proof when the chain proof passes a confirmation of a sufficient number of validators (to reach the preset verification threshold). This multi-node verification mechanism further reduces the trust risk, and a wide range of validators can share the benefits generated during the cross-chain process while participating in providing additional security guarantees to the network.
- MBSN (Massive Bitcoin Supervisor Network) : acts as a supervisor in the BitVM Peg-In process. Peg-In refers to the process by which a user locks BTC on the Bitcoin main chain. The MBSN node is responsible for monitoring whether the light client in the target chain regarding the Bitcoin locked state is consistent with the Bitcoin main network. That is to say, when the user locks BTC on the Bitcoin main chain, the target chain (such as Ethereum or other chains) will receive corresponding Bitcoin block headers and transaction proofs; the MBSN verifies whether the status on these chains truly reflects the situation of the Bitcoin main chain, preventing the target link from being forged Bitcoin block information. Through distributed supervision and launching the SuperBlock challenge process on the target chain when necessary, MBSN can ensure data consistency and effectiveness of cross-chain delivery of Bitcoin state in the Peg-In stage.
- MBCN (Massive Bitcoin Challenger Network, Large-scale Bitcoin Challenger Network) : Act as a challenger in the BitVM Peg-Out process. Peg-Out refers to the process by which a user burns anchored assets in the target chain to retrieve Bitcoin. The MBCN node closely monitors unlock requests for these locked BTC on the Bitcoin main chain. When someone tries to illegally unlock BTC without valid cross-chain proof support, MBCN will immediately discover and trigger the challenge mechanism on the Bitcoin main network. Specifically, the BitVM2 protocol on the Bitcoin main chain will set a challenge window, and MBCN can submit fraud evidence to prove that a Peg-Out unlock request is illegal, thereby preventing improper fund unlocking. Through this challenge network, even if malicious behavior occurs in individual links, the system can still ensure the security of the cross-chain bridge based on the assumption that “there is at least one honest challenger”.

The above modules cooperate with each other to achieve a cross-chain bridge infrastructure with minimal trust and capable of verifying states across multiple blockchains. OLA extends Bitcoin’s security model into inter-chain interactions: funds are escrowed by smart contracts and BitVM2 scripts and combined with the supervision of multiple validators, and cross-chain bridges can be safely run with minimal trust assumptions (such as 1-of-N participants’ honesty).

OLA technical process overview

In order to ensure trusted synchronization of multi-chain states, OLA has built a set of inter-chain proof transmission and state verification mechanisms, covering the generation, submission, verification of chain state proofs, as well as supervision and challenges during cross-chain operation:

Chain Proof Submission and Verification : When Myriad Chain Prover generates a new zero-knowledge proof of blockchain status for a chain, the proof will be submitted to the Onis network. Subsequently, a large number of MVN verification nodes will verify the proof in parallel. Each verifier independently runs the zero-knowledge proof verifier program to confirm that the proof does prove that the block header hash sequence of the corresponding chain is valid and continues to the latest height. Once enough validator reports prove valid and the system preset verification threshold is reached, MVN will submit this result to the Onis on-chain contract. After receiving sufficient verification signature or statistical information on the Onis contract, it performs on-chain contract verification on the proof. After the verification is successful, the status proof can be accepted on the chain, and the new status root of the corresponding chain (such as the latest block header hash) is recorded in the Onis state proof. The entire process implements an off-chain generation-off-chain verification-on-chain confirmation inter-chain state proof delivery process: off-chain zero-knowledge proof provides efficiency, decentralized majority verification provides security guarantee, and the on-chain contract is finally anchored to the state, thus ensuring that cross-chain state updates are both efficient and trustworthy.
Peg-In State Supervision (MBSN) : During the process of user initiating Peg-In (cross-chain BTC from the Bitcoin main network), the MBSN node assumes key supervision responsibilities. When a user locks Bitcoin in the BitVM2 protocol script of the Bitcoin main chain, the corresponding lock event needs to be recognized by the target chain. In specific implementation, the target chain (probably Onis Rollup or other cooperative chain) will run a Bitcoin light client module, tracking the Bitcoin block headers and verifying the Merkel proof of a specific locked transaction . The MBSN network monitors this process to verify the correctness of the Bitcoin headers and transaction proof received by the target link. If the Bitcoin light client status of the target chain is inconsistent with the actual Bitcoin chain (for example, a malicious node provides the wrong block header to the target chain contract), the MBSN can discover and initiate the challenge process. Under normal circumstances, a sufficient number of MBSN verifications will make the target chain convince the Bitcoin lock has indeed occurred, triggering the minting of corresponding anchor assets (such as Peg-BTC) on the target chain. Through MBSN supervision, the inter-chain state transmission in the Peg-In process maintains high integrity, ensuring that the locked state of the Bitcoin main chain is truly reflected in the cross-chain system.
Peg-Out Challenge Mechanism (MBCN) : Peg-Out is the process by which users destroy anchored tokens on the target chain to redeem Bitcoin. Since the Bitcoin main chain ultimately performs BTC unlocking, it is crucial to ensure that only a legitimate redemption request can unlock BTC to the correct address. To this end, BitVM2 bridge scripts are usually designed as unlock (exit) mechanisms with delays, setting a challenge period after the user initiates a redemption request. In this window, the MBCN node will review the corresponding cross-chain proof and transaction: check that the user has indeed burned the equivalent Peg-BTC on the target chain, and that the Peg-Out request complies with the protocol rules. If someone tries to bypass the normal process and falsify proofs directly request unlocking from the Bitcoin contract, MBCN will challenge immediately. The challenge includes submitting evidence of fraud (such as proving that the user has not destroyed tokens on the target chain, or providing contradictory chain status), triggering the BitVM2 protocol to refuse this unlocking and confiscate the margin of the offender. This challenge mechanism is based on the optimistic assumption that illegal withdrawals can be prevented by assuming that at least one of the many observers is honest. Therefore, MBCN ensures that there are enough challengers to monitor the effectiveness of transactions online in the Peg-Out stage, further consolidating the security of the trust model of the cross-chain bridge.
Multi-chain state synchronization (Onis) : As the core module of the zk light client of each chain, Onis assumes the responsibility of maintaining trusted synchronization of multi-chain state. When a chain's new state proof passes the verification threshold and is verified by the Onis contract, Onis updates its status record about the chain (such as the latest block hash or status root). Over time, the status of different chains will continue to be submitted and updated in Onis through the above process. Since the updates of each chain are zero-knowledge proof and decentralized, the chain states stored on Onis can be considered as trusted images of multi-chain states. In other words, Onis provides a trustless synchronous view for multiple blockchains: anyone or DApp can query Onis to get the latest status of Bitcoin or other chains without running full nodes on its own or trusting data provided by third parties. This multi-chain synchronization capability means that the Bitcoin ecosystem can achieve state interoperability with other chains with the support of Onis. In short, Onis uses zero-knowledge proof to bring consensus security of each chain into cross-chain scenarios, maintaining the consistency and reliability of multi-chain states.

Through the above mechanism, OLA implements a closed-loop process from proof generation to verification acceptance to state synchronization across chain states. In this process, no centralized entity can unilaterally tamper with the cross-chain state: only valid on-chain proof can be effective on the target chain by the approval of most verifiers. In the process of cross-chain asset flow, the Supervisor Network and the Challenger Network always guarantee the honesty of the process. Once an exception is detected, the system can respond in a timely manner to ensure consistency in the final state and security of funds. This design enables the connection between Bitcoin and other chains to be built on cryptographic proof and decentralized consensus, enabling true minimal trust cross-chain bridges.

OLA main network progress and online planning

The development and deployment of various modules of the OLA project are gradually being promoted in accordance with the plan, and important phased results have been achieved:

OLA Control HQ (Control Hub) : The development work of this hub module has been completed, realizing unified scheduling and external interfaces for each verification and proof module. Control HQ is currently running stably, providing task orchestration and RPC service support for testnets and developers.
Onis Test Network : The Onis Test Network version has been developed and deployed. Developers and partners can verify Onis's function of synchronizing and verifying multi-chain states through the test network, simulating the cross-chain operation process of Bitcoin and other chains. The launch of the test network marks the entry of OLA core functions into actual testing.
MVN (Massive Verifier Network) : The Massive verification network has been operating stably for nearly a year. Up to now, more than 235,000 validators distributed in more than 180 regions around the world have participated, and a total of about 874 million verification results have been produced. This huge mobile ZKP verification network provides OLA with a solid decentralized verification foundation, verifying its scalability and security in actual operation.
MBSN and MBCN : The development of the core modules of the two major Bitcoin supervision/challenge subnets has also been completed. At present, these two modules are being coordinated and connected with Bitcoin-related project parties. That is, OLA is working with other teams in the Bitcoin ecosystem to test light client interaction and challenge mechanisms in the Peg-In/Peg-Out process to ensure that MBSN and MBCN can be seamlessly integrated into actual cross-chain bridge applications. Once the integration is completed, these networks will formally assume the supervision and challenge responsibilities, further improving the security closed loop of OLA cross-chain bridge.
Myriad Chain Prover : As a key module for OLA to provide zero-knowledge chain proof, Myriad Chain Prover is currently in accelerated development. The development team is conquering ZK circuit optimization and performance tuning for multi-chain block header verification, and plans to complete the research and development of its core functions in the second quarter. At that time, OLA will have the ability to prove efficient chain status for multiple chain outputs, and prepare for main network deployment.
Main network online planning : According to the project roadmap, the main network version of all OLA modules (including Control HQ, Onis, Myriad Chain Prover, Massive network submodules, etc.) is expected to be launched in the third quarter. After the main network is online, OLA will be open to users and developers to use it to realize the real value connection between Bitcoin and the multi-chain ecosystem. Before the main network is online, the team will continue to conduct security audits, performance testing and multi-party joint communication to ensure that the online cross-chain bridge infrastructure is safe and stable enough.

Through the above milestone progress, OLA is gradually moving from conceptual design to practical deployment. The test network data and the long-running Massive verification network provide strong support for the main network, making us full of confidence in the upcoming main network stage.

Summary of the Outlook

OLA has brought structural cross-chain trust capabilities to the Bitcoin ecosystem by innovatively combining cryptography and decentralized networks. With the help of zero-knowledge proof technology and BitVM2 protocol, the security model of cross-chain interaction has been fundamentally changed. A large number of distributed validators and supervisors have participated together, which makes the system have strong anti-censorship and fraud capabilities, truly realizing the original design intention of "minimizing trust".

This native cross-chain connection base has far-reaching significance: first, it allows Bitcoin assets to flow freely and safely in a multi-chain world. Users will be able to use BTC on smart contract platforms such as Ethereum to participate in DeFi, NFT transactions and other innovative applications without worrying about custody risks and trust thresholds. This will release the huge value that Bitcoin has accumulated over a long time and empower BTC with more diverse application scenarios. Second, the emergence of OLA provides a scalable general infrastructure for cross-chain bridges. In the future, any blockchain that wants to interact with Bitcoin can integrate OLA's proof of chain and state synchronization services, thereby quickly building a secure cross-chain bridge without the need to remake the wheel. In this way, OLA will promote Bitcoin to truly integrate into the multi-chain ecosystem and become the value center between each chain.

In the long run, OLA is committed to becoming a decentralized trust bridge for the Bitcoin ecosystem, connecting the world of Bitcoin assets worth up to trillions of dollars and a rich and diverse blockchain application. With the main network online and the ecosystem expanding, more and more users and project parties will participate in the OLA network to jointly verify and witness each state update of cross-chain interaction. Bitcoin will no longer be an island, but will be interconnected with other networks through OLA's bridges while maintaining its own security. Such interoperability will greatly improve Bitcoin's capital efficiency and application potential, bringing new opportunities to decentralized finance and Web3.

In short, what OLA is building is not just a cross-chain bridge application, but an underlying trust layer. It uses cryptography as its shield and community network as its cornerstone, providing unprecedented security and freedom for Bitcoin cross-chain. Through OLA, the value of Bitcoin can be circulated in the multi-chain ecosystem without any hindrance, and the innovations of each chain can also absorb the liquidity and security of Bitcoin. This virtuous cycle will promote the integrated development of the entire blockchain industry. Our outlook for OLA is: With the maturity and expansion of technology, it will become a key pillar for Bitcoin to move towards a multi-chain future, allowing the most primitive and trustworthy crypto assets to shine more vitality in the new era.