Charging Fees - V2

[GabrielePicco]

Scenarios

1. General Case: A node wants to charge fees in SOL (a fraction of what it would cost on the base layer) and profit from the difference between fees - (costs of infra + commits + security committee + DA).
2. Gasless Transactions: A node operator may choose to remove transaction costs for users and cover the costs of commit/undelegation and resizing themselves. An example of this is Zeebit, which aims to abstract fees as it monetizes through casino games. In this scenario, the node could process only transactions from whitelisted programs (e.g., programs they developed).
3. Alternative Payment Tokens: An entity (e.g.: StarAtlas) want users to pay fees with a different token (e.g. Atlas). See octane: Octane GitHub.

Description

• Lamports IN: Enter lamports from the ER (trough controlled flow)
• Lamports OUT: Exit lamports from the ER (trough controlled flow)
• Backdoor IN: Cloned delegated accounts lamports
• Backdoor OUT: Resize/Close committed accounts

Discussed Approaches

Approach 1.

• IN lamports: Users entering the ER have to spend 1 solana-mainnet-lamports for 1 ephemeral-lamports
• OUT lamports: Lamports can exit ER in any ways, as ratio is 1:1
• ephemeral-lamports = solana-mainnet-lamports = every lamport in the ER has SOL collateral

Approach 2.

• IN lamports: SPL token atlas, Ratio is 0.1, Users entering the ER have to spend 10 atlas for 1 ephemeral-lamports. Mandatory that no lamports can enter by backdoors (currently possible)
• OUT lamports: lamports taken out follow conversion ratio. I can redeem 1ephemeral-lamports for 10 atlas. Mandatory that no lamports can exit ER by backdoors (currently possible)
• ephemeral-lamports = ratio of an SPL token = every lamport in the ER has an SPL collateral

Notes

• Approach 1 Addresses scenario 1. Scenario 3 is not feasible with backdoor IN/OUT, lamports need to be priced in SOL.
• Approach 2 Addresses scenario 1, 3 but is more complex as no backdoor IN/OUT should exists
• With both 1/2 validators can cover costs up-front, for every action (resize, commits, ...) someone spent real collateral in the ER. The validator can then claim costs + reward.
• Both approaches can support 2 with small modifications. Ephemeral lamports are minted for "free". Resizing is avoided allowing only whitelisted programs to be cloned/executed in ER

Other discussed implementations

• Paying for space and CU with different currencies. Several downsides including users have to top-up ER keypair with SOL + another SPL token. Additionally need an alternative tracking/charging mechanism parallel to SVM execution.

See #118 for the full discussion