The Rayls Commit Chain is an EVM blockchain that is the hub connecting each of the Privacy Ledgers within a Rayls Private Subnet. All on-chain messages and transactions flow between Privacy Ledgers via the shared Commit Chain of the Private Subnet.

All inter-PL transactions are encrypted and stored to the Commit Chain's blockchain ledger, creating an immutable record of transactions that can only be decrypted by the parties directly involved in the transaction (see the EVM Privacy page for more information).

In addition to keeping an immutable record of encrypted transactions, the Commit Chain also maintains the state of Subnet by validating cryptographic proofs that are regularly submitted by each Privacy Ledger and enforces the Subnet governance policies, as set by the Subnet Governor.

Purpose

The Commit Chain therefore ensures the legitimacy, validity and consistency of the state and interactions across the Private Subnet.

1. Legitimacy

On the Commit Chain, managed by the Subnet Governor, there is a registry of all approved Privacy Ledger members (the Member Registry) and a registry of all approved tokens that can be transacted across the Subnet (the Token Registry). As Privacy Ledgers transact with one another, validation checks can be made against these registries, including checking the status of a specific member or token (i.e. to ensure they are still active, not frozen or deactivated).

For each registered token, a copy of the token's smart contract is stored on the Commit Chain and automatically deployed on demand to a Privacy Ledger (via its Relayer) when receiving this token for the first time. This ensures that the token being received is the exact same as the token that was registered (not a fake) and also enables smoother token upgradability, where updates can be made to the token contract on the Commit Chain and broadcast to the Privacy Ledgers of the Subnet.

Similarly, when a Privacy Ledger is receiving a token, there is a validation step to ensure that the token was indeed minted by the original Issuer (the Privacy Ledger that originally minted and registered the token, not a fake).

2. Validity

To ensure transaction validity, preventing fraud or double spend, Rayls imposes validation steps that occur during every transaction, utilising cryptographic proofs that are submitted by the transacting Privacy Ledgers.

There are two main proofs that are compared to conduct this validation:

Time-base state commits: a PL's internal block headers are published as a proof to the Commit Chain every few seconds
Transaction proofs: submitted by both sending PL and receiving PL as part of each inter-PL transaction across the Commit Chain, orchestrated by the Rayls Protocol

Automated validation checks are conducted for each transaction to compare the transaction proofs with the latest time-based state commits to ensure that the transaction is valid (there has been no double spend nor fraudulent activity). If a transaction is not valid, it will fail and the issue will be identified by the Flagger.

3. Consistency

The Commit Chain is the single source of truth for all (encrypted) messages and transactions across the Subnet - all inter-PL transactions are recorded to the Commit Chain ledger. By comparing the various cryptographic proofs submitted by Privacy Ledgers (time-based state commits and transaction proofs) the Commit Chain can ensure the consistency of state across the Subnet.

As all tokens that are transferred between Privacy Ledgers are registered with the Commit Chain (including their total minted supply), the Commit Chain can compare these reference points using ZK to validate the total circulating supply and net balances of each registered token and ensure that this is consistent with the network state, further preventing fraud and double spend within the Subnet.

Core Functions

1. Transaction Coordination

The Rayls Commit Chain is responsible for managing and validating transactions between Privacy Ledgers. It ensures that transactions are consistent, tamper-proof, and follow the rules and protocols set by the network governance.

Validation: The commit chain validates transactions to ensure they meet all necessary criteria before being committed.
Atomicity: Supports atomic transactions, ensuring that all parts of a transaction are completed successfully, or none are, preventing partial execution.

2. Finality and Proofs

The Commit Chain provides immutable transaction finality, meaning that once a transaction is included on the Commit Chain ledger, it cannot be altered or reversed. It also manages cryptographic proofs that ensure the integrity and validity of transactions.

Proofs Management: Handles the creation and storage of cryptographic proofs that can be used to verify the authenticity of transactions.
Immutability: Once a transaction is committed, it becomes a permanent part of the blockchain, ensuring a transparent and tamper-proof record.

3. Privacy and Security

Maintaining privacy and security is a top priority for the Rayls Commit Chain. It ensures that transaction details are kept confidential while still allowing necessary validations and audits.

Confidential Transactions: Transaction details are encrypted and only visible to authorised parties, protecting sensitive information.
Regulatory Compliance: The commit chain supports compliance with legal and regulatory requirements by enabling secure and transparent audit trails.

4. Interoperability

The Rayls Commit Chain facilitates cross-chain interoperability between Privacy Ledgers (as each Privacy Ledger is itself an independent blockchain), enabling secure and efficient cross-chain transactions.

Cross-Chain Transactions: Supports the seamless execution of transactions across different blockchains, maintaining privacy and security throughout the process.
Interoperable Protocols: Compatible with various blockchain protocols to ensure composability and ease of integration.

Governance and Control

The Rayls Commit Chain includes robust governance mechanisms to ensure that all transactions and operations within the network adhere to established rules and standards.

1. Governance Policies

Governance policies are enforced programmatically via smart contracts, ensuring that all transactions and operations comply with the network’s rules.

Policy Enforcement: Smart contracts automatically enforce governance policies, reducing the risk of human error and ensuring consistency. These governance contracts can only be implemented and amended by the Subnet Governor.
Customisable Policies: Governance policies, determined by the Subnet Governor, can be tailored to meet the specific needs of different users and regulatory environments.

2. Control Mechanisms

The commit chain includes control mechanisms that allow for the freezing, locking, and seizing of assets when necessary, providing additional layers of security and compliance.

Asset Freezing: Temporarily halts the transfer of specific assets to prevent unauthorized transactions or fraud.
Asset Locking: Restricts access to certain assets under specific conditions, ensuring they are only used as intended. Feature coming soon
Asset Seizing: Allows for the seizure of assets in accordance with legal and regulatory requirements. Feature coming soon

Scalability and Performance

The Rayls Commit Chain is designed to handle high transaction volumes, providing scalability to meet the needs of large financial institutions and other enterprise users.

Depending on the blockchain platform selected for the Commit Chain (it can be any EVM-based platform, but we recommend Hyperledger Besu), transaction throughput may be limited by the TPS of that platform.

To overcome this limitation, Rayls provides an efficient batching approach such that transactions (thousands) are batched by the sending Privacy Ledger and the batch is then posted to the Commit Chain as a single transaction.

As such, the TPS of the Subnet overall can be in the tens of thousands of transactions per second (depending on configuration and transaction types), which more than satisfies the throughput requirements of inter-financial institution settlement.

Conclusion

The Rayls Commit Chain is a powerful and essential component of the Rayls ecosystem, ensuring the legitimacy, validity and consistency of the Private Subnet to support next-generation financial transactions. By acting as a secure hub that connects the Subnet's Privacy Ledgers, the Commit Chain ensures that all transactions are validated, recorded, and governed according to the highest standards of privacy and compliance.

For more information on how to use the Rayls ecosystem in your operations, please refer to our detailed integration guides and API documentation.