Pool-based lending

[bonomat]

I had an idea of how we can build a pool-based lending protocol.

1. (tx_join_pool): Maker_1-Maker_n join a pool by collaboratively funding pool_contract. For that they receive lender_token according to their shares.
2. (tx_take_loan): A taker comes and executes the contract by spending pool_contract. This contract enforces that a certain amount of collateral has to end up in pool_contract
3. (tx_repay_loan): The lender repays the loan. The principal amount + interest are locked in lender_holder_contract. The taker can take the Bitcoin
4. (tx_liquidate_loan): Anyone can liquidate but has to pay back the the principal. For that she can take the Bitcoin collateral. The principal amount ends up in lender_holder_contract.
5. (tx_exit_pool): After the loan was paid back, a maker can exit the pool by spending from the lender_holder_contract and providing his maker_n_lender_token. The token gets burned and the maker receives his money.

Some thoughts:

• 4: since the whole approach is async, a liquidation has to ensure that the makers get their funds back. hence, in a liquidator has to pay back the loan to the pool but receives the collateral. An alternative would be where the lenders would receive the BTC. However, time matters, and the lenders might not be able to exit fast enough to sell their BTC and would end up with a loss.

Some questions which came up:

• 1-5: How can we keep assets/amounts confidential