# Private Yield

### Aave Integration

To start, Sacred will integrate with Aave to offer private lending.

Paying out the yield gained directly from a lending platform like Aave during withdrawal might hint at how long assets stayed in a [Sacred Box](https://sacred.gitbook.io/sacred-finance/how-sacred-works/broken-reference). An observer or bad actor could then calculate how long the asset has been in the Sacred box, and knowing the withdrawal time could determine the depositing address. Therefore, breaking the link between the principal and the yield earned is essential.&#x20;

### How Shares-of-Staked-Second Model works:

![](https://lh3.googleusercontent.com/gUyMa1zsp7GSfSWYdPjW5plGlSSasNihn06QL-4e9MbShHFGk4sJ1JZV8s_-Y8fgLG92O3Dvk7VfC5HjC9uDr31o23EIqc1wHSaFeDQInTmA9E8H4tyySiWTOp9udMVV0zEj2TMntciJ_IBpPg)

Sacred uses a **shares-of-staked-seconds** method to calculate the interest earned by each user. For each Sacred pool, all users’ principals are pooled together to earn yield. For each transaction, the yield is pooled together into a smart contract. The user gains a share of the pooled yield rather than the yield paid directly by Aave. The yield earned depends on the amount of a user’s deposit and the time they stayed in the Sacred protocol.

Because the Interest Earned is compounded, the amount of time spent in the protocol is essential to know to give users a fair share.

As we cannot directly link each user’s deposit and withdrawal timestamps because of privacy, we use the Share Tracking Mechanism.&#x20;

The user’s share is the ratio of time that their deposit earned interest in the Sacred Pool to the total time of all deposits currently earning interest in the Sacred pool.

When a user withdraws their deposit, there is a time delay until they can claim the interest earned on their deposit. During that time delay, the portion of their interest is earning interest. However, the system does not track this time. We also do not know how much interest that user has accumulated at the withdrawal time. Unlike the deposit amounts of a fixed denomination, the interest amounts vary by user. Leaking the time delay between the withdrawal and interest claim has privacy consequences.

Therefore, the amount of interest earned on users’ unclaimed interest will be added to the total amount of interest and distributed to all users according to their share of the interest.

A user can withdraw the principal and yield in separate transactions. This flexibility allows the user to redeem their yield earned all at the same time at a later date after making multiple deposits and withdrawals in a Sacred pool. While users can redeem the YIELD accumulated all at once from principals, stagger principal redemption and NEVER do this simultaneously as it will compromise privacy!
