The Lightweight Transaction Model
5.1 Overview of the Everlight Transaction Model
Bitcoin Everlight implements a streamlined transaction model designed to facilitate rapid Bitcoin payments without the operational complexity of channel-based systems. The core innovation is the processing of Lightweight Transaction Verification events (LTV events) that enable near-instantaneous confirmations while maintaining essential security properties. These LTV events represent a layer of verification that exists above the Bitcoin blockchain but below the application layer.
It is crucial to understand that Everlight does not function as an independent settlement ledger. Bitcoin remains the ultimate settlement layer and source of truth for final transaction state. Everlight instead provides an intermediate verification layer that enables practical transaction speeds while periodically anchoring to Bitcoin’s security foundation.
5.2 Transaction Structure
The Everlight transaction structure maintains compatibility with Bitcoin’s fundamental addressing and value transfer model while introducing lightweight metadata for efficient processing. A transaction can be formally represented as:
$$T = {A_s, A_r, V, \tau}$$
Where:
$A_s$ represents the sender’s address
$A_r$ represents the receiver’s address
$V$ represents the value being transferred
$\tau$ represents timestamp or sequencing metadata
This structure enables efficient routing and verification while maintaining compatibility with Bitcoin’s addressing scheme.
5.3 Verification Logic (High-Level)
The verification process in Everlight employs a multi-faceted approach that ensures transaction validity without the computational overhead of full Bitcoin consensus. This verification can be represented as a logical function:
$$V(T) = \sigma_1(T) \land \sigma_2(T) \land \sigma_3(T)$$
Where:
$\sigma_1(T)$ represents basic validity checks including signature verification and proper formatting
$\sigma_2(T)$ represents balance or authorization verification
$\sigma_3(T)$ represents node-level routing confirmation
For a transaction to be considered valid, all three verification components must evaluate to true. This approach differs fundamentally from Bitcoin’s consensus-level validation, which requires global network agreement and inclusion in the blockchain. Instead, Everlight’s verification occurs within a subset of nodes, enabling significantly faster confirmation times while maintaining sufficient security for everyday transaction values.
The verification logic can be expanded to include specific checks:
$$\sigma_1(T) = \text{ValidSig}(T, A_s) \land \text{ValidFormat}(T)$$ $$\sigma_2(T) = \text{SufficientBalance}(A_s, V) \land \text{AuthorizedTransfer}(A_s, A_r, V)$$ $$\sigma_3(T) = \text{RoutingAvailable}(A_s, A_r) \land \text{NodeQuorumReached}(T)$$
This layered verification approach enables rapid transaction confirmation while preventing common attack vectors.
5.4 Routing & Confirmation Model
Everlight employs a node quorum model to establish transaction confirmation without requiring global consensus. This approach balances security with performance by requiring agreement from a sufficient subset of nodes rather than the entire network.
The minimum quorum size for confirmation can be expressed as:
$$Q = \lceil k \cdot N \rceil$$
Where:
$N$ represents the number of nodes in the local routing cluster
$k$ represents the quorum coefficient $(0 < k \leq 1)$
$\lceil \cdot \rceil$ represents the ceiling function (rounding up to the nearest integer)
A transaction is considered confirmed when the number of confirming nodes meets or exceeds the quorum threshold:
This quorum-based approach ensures that transactions receive sufficient verification to prevent fraudulent activities while enabling rapid confirmation times. The specific value of the quorum coefficient $k$ is determined by network parameters and may be adjusted based on security requirements and operational conditions.
5.5 Transaction Lifecycle
The Everlight transaction lifecycle follows a defined sequence from initiation to confirmation. This process can be visualized as a sequential flow:
Each stage in this lifecycle represents a distinct phase in transaction processing:
Submit Transaction: The user initiates a transaction through an Everlight-compatible wallet, which constructs the transaction according to the structure defined in Section 5.2.
Everlight Routing Layer: The transaction enters the Everlight network and is propagated to relevant nodes based on network topology and routing efficiency.
Node Cluster Evaluation: A cluster of Everlight Nodes evaluates the transaction according to the verification logic described in Section 5.3, checking validity, balance, and routing availability.
Quorum Confirmation: Nodes signal their confirmation according to the quorum model outlined in Section 5.4. Once sufficient confirmations are received, the transaction is considered confirmed within the Everlight layer.
Rapid Receipt Issued: A confirmation receipt is issued to both sender and recipient, providing cryptographic proof of the transaction’s acceptance by the Everlight network.
Optional Settlement Anchoring: Periodically, batches of confirmed transactions may be anchored to the Bitcoin blockchain through a settlement process, providing additional security assurances for high-value or sensitive transactions.
This streamlined lifecycle enables transaction confirmation in seconds rather than minutes or hours, making Bitcoin suitable for everyday payment scenarios.
5.6 Fee Model (High-Level)
The Everlight fee model is designed to provide predictable, low-cost transaction processing regardless of Bitcoin network congestion. The fee structure can be represented as:
$$F(T) = \mu + \lambda \cdot S$$
Where:
$F(T)$ represents the total fee for transaction $T$
$\mu$ represents the base micro-fee
$\lambda$ represents the size coefficient
$S$ represents the transaction size
This fee model ensures that transaction costs remain predictable and economically viable for everyday use cases, including small-value transactions. The base micro-fee $\mu$ provides a floor that ensures minimum compensation for node operators, while the size component $\lambda \cdot S$ scales with transaction complexity.
Unlike Bitcoin’s fee market, which fluctuates based on block space demand, Everlight’s fee structure remains stable and predictable. This predictability enables accurate fee estimation for users and merchants, facilitating broader adoption for everyday commerce.
5.7 Optional Bitcoin Settlement Anchoring
The Everlight transaction model includes an optional settlement anchoring mechanism that periodically records transaction state to the Bitcoin blockchain. This process provides an additional layer of security by leveraging Bitcoin’s robust consensus while maintaining Everlight’s speed advantages for day-to-day operations.
The settlement process can be represented symbolically:
$$B = \text{hash}({T_1, T_2, \ldots, T_n})$$
Where:
$B$ represents the batch identifier
$\text{hash}(\cdot)$ represents a cryptographic hash function
${T_1, T_2, \ldots, T_n}$ represents a set of Everlight transactions
This batch identifier is then recorded on the Bitcoin blockchain through a standard Bitcoin transaction, creating an immutable reference that can be used to verify the integrity of the Everlight transaction history. The frequency of settlement anchoring can be adjusted based on security requirements and operational considerations.
The settlement anchoring process provides several key benefits:
Enhanced security for high-value transactions
Protection against potential attacks on the Everlight layer
Compatibility with Bitcoin’s security model
Auditability and verification against the Bitcoin blockchain
This optional mechanism allows users to choose their preferred balance between immediate confirmation and settlement finality based on their specific use case requirements.
5.8 Summary
The Bitcoin Everlight lightweight transaction model offers a pragmatic approach to scaling Bitcoin for everyday use cases. By implementing a streamlined verification process that operates above the Bitcoin blockchain but below the application layer, Everlight enables rapid transaction confirmation without the complexity of channel-based systems.
The key advantages of this lightweight model include:
Simplicity: The model eliminates the need for channel management, liquidity balancing, and complex routing algorithms, reducing both technical and operational overhead.
Speed: Transactions can be confirmed in seconds rather than minutes or hours, making Bitcoin suitable for point-of-sale and time-sensitive payment scenarios.
Usability: The streamlined approach reduces friction for both users and merchants, lowering the barrier to Bitcoin adoption for everyday transactions.
Compatibility: The model maintains fundamental compatibility with Bitcoin’s security foundation through optional settlement anchoring, allowing users to leverage both Everlight’s speed and Bitcoin’s security as needed.
This lightweight transaction model represents a balanced approach to scaling Bitcoin, addressing its practical limitations for everyday use while respecting its fundamental security properties. By providing a complementary layer that enhances rather than replaces Bitcoin’s core functionality, Everlight extends Bitcoin’s utility without modifying its protocol or consensus rules.
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