A simple deposit instrument for cryptocurrency tokens.
Deposit and withdraw into a common pool, managed by a smart contract. Withdrawals are subject to a constant percentage fee, no matter the duration of deposit. Fees are redistributed proportionally to active deposits.
The Python simulation implements O(1) updates per deposit/withdrawal operations, as required by a smart contract environment, where an iteration over all deposits would be prohibitively expensive.
Implemented for Ethereum, in Solidity. Uses truffle framework for testing.