> For the complete documentation index, see [llms.txt](https://docs.btcd.fi/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.btcd.fi/security-and-audits.md).

# Security and Audits

Independent security reviews of the Bitcoin Dollar contracts, their scope, and the operational controls around them.

Our protocol smart contracts have undergone rigorous third-party audits before deployment, ensuring the safety of user funds and the integrity of our collateral management mechanisms.

This page contains the set of completed audit reports from trusted and experienced security firms specializing in blockchain protocol security. Our auditors have examined our smart contract architecture, including the BTCD minting and redemption logic, rebalancing mechanisms, and collateral management systems. The published reports represent their findings and our remediations.

As new contracts are deployed, we'll publish updated additional audit reports here. Users and developers should review the audits as part of their own due diligence.

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## Verification

The BTCD, sBTCD, bdUSD and BTCdc contracts are source-verified on Etherscan. Verification is not a security review. See [Deployments](/technical-documentation/deployments.md).

## Operational controls

These controls are part of how the engine runs. They are not security-review findings.

* Every DeFi transaction is simulated before it is sent, and every swap, deposit and withdrawal has a slippage limit.
* Minting and redemption have per-block limits, and quotes are refused on stale data.
* Settings change only through proposals signed by the required approvers.
* Transactions are signed through an institutional custody platform whose policies limit which contracts each account may call.

See [Controls and governance](/how-the-engine-works/controls-and-governance.md).