Fee-Based Tokens in Nano: Behavior and Scenarios

[raul-oliveira]

I’ll use this issue for us to decide (and vote) a few things related to the behavior of fee-based tokens in Nano.

In the UTXO world, we calculate the number of outputs to determine the fee value. In the Nano world, we don’t have outputs.

Some scenarios have been raised:

UTXO vs NC – Action

When a transaction makes a deposit into a nano contract. For example, a transaction with:

• 1 input with 5 FBT
• 1 output with 2 FBT
  • ✅ Here we already charge 0.01 HTR for output count
• 1 deposit into nano with 3 FBT
  • ❓ Should we also charge 0.01 HTR here?

Nano Contract

Below is my opinion for the topics.

Syscall (NC)

Create Token

• 0.01 HTR is charged when creating a fee-based token

Mint

• 0.01 HTR is charged when minting a fee-based token

Melt

• 0.01 HTR is charged when melting a fee-based token

NC vs NC – Action

Deposit

• Charge 0.01 HTR when making a deposit from one NC to another NC

Withdraw

• Charge 0.01 HTR when withdrawing from one NC to another NC

Fee in the Nano Universe

The fee will be calculated and will be charge similar to how the deposit tokens works.

[raul-oliveira]

Reviewers @msbrogli @obiyankenobi

[msbrogli]

I guess we should consider deposits as outputs and withdrawals as inputs when calculating fees. So, fees will be 0.01 * (len(outputs) + len(deposits)).

We should also consider any transfer between contracts as the equivalent of deposits and withdrawals. So, 0.01 * len(transfers between contracts).

Token creation, mint and melt should apply the same fee as the one used in utxos.

[obiyankenobi]

I agree with Marcelo and Raul. As I understand, your proposals are in agreement. Just highlighting as Marcelo that in transfer between contracts we should charge 0.01 HTR per fee-based token.

[raul-oliveira]

Sounds good. I'll the scenarios to the dynamic transaction model RFC.