Controller

The primary task of the EVC is to maintain a user's voluntary associations with vaults. Typically, a user will deposit funds into one or more collateral vaults, and call enableCollateral for each that is intended to be used as a collateral. This adds the vault to the given account's collateral set. Users should obviously be careful which vaults they deposit to, since a malicious vault could refuse to return their funds.

After simply depositing and enabling collaterals, users are not obligated or bound in any way by the EVC, and could freely withdraw funds from the vaults and/or call disableCollateral to remove the vaults from the account's collateral set.

However, suppose a user wants to take out a borrow from a separate vault. In this case, the user must call enableController to add this vault to the account's controller set. This is a significant action because the user is now entirely submitting the account to the rules encoded in the controller vault's code. All the funds in all the collateral vaults are now indirectly under control of the controller vault. In particular, if a user attempts to withdraw collateral or disableCollateral to remove a vault from the collateral set, the controller could cause the transaction to fail. Moreover, the controller can allow the collateral to be seized in order to repay the debt, using controlCollateral.