# Sybil Contract - NADABOT

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The Sybil attack in computer security is *an attack wherein a reputation system is subverted by creating multiple identities*
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Although for direct donations that do not have tax benefits, there is minimal impact if someone is using unique accounts for donations. However, when it comes to democratic voting / funding systems like quadratic funding, we need to make sure that the system is not being gamed and that our subsequent funding contracts are checking for definitions of humans.

[https://app.nada.bot ](https://app.nada.bot)

To solve this Nada.bot has emerged allowing for other sybil providers and contracts to develop "checks" or "stamps" if you are familiar with [Gitcoin Passport's](https://passport.gitcoin.co/) model. 

{% embed url="<https://github.com/PotLock/core/tree/main/contracts/sybil>" %}

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Up to date docs are on[ https://docs.nada.bot ](https://docs.nada.bot)
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<figure><img src="https://2305343534-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FUYoundifYZUyZHQYnZyO%2Fuploads%2F7gqatAhd6V2yY9n9d7ow%2Fnadabotsocialpreview.png?alt=media&#x26;token=993f4fc4-3c7f-4708-a832-4123333b817f" alt=""><figcaption></figcaption></figure>

## Where is this used?

This is\_human check on nadabot.near is used by default in Pot deployments. While a deployer can specify their own configuration for different checks with their own weights and human threshold.

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See PotDeployer to see how to configure your human check
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