# Proof of Humanity FAQ

## What is the purpose of Proof of Humanity?

Proof of Humanity (PoH) is a system designed to create a trusted list of humans, verified by a decentralized community. This system is designed to be used by individuals as a gateway to various new applications that require Sybil-resistance to function effectively. It can also be integrated into a wide range of existing and future applications that need reliable identity systems.

## Why should I register to PoH? What are its use cases?

Proof of Humanity is a decentralized system that creates a trusted list of verified humans by having users submit their name, photo, and video, which are then vouched for by existing members. Registering with PoH ensures that you are recognized as a real person, preventing duplicates and bots. 

The benefits include secure online voting, fair UBI distribution, a more authentic social media experience, and more. PoH also enhances trust in peer-to-peer marketplaces and serves as a universal login method for decentralized applications. By registering, you help create a more secure and trustworthy digital environment for various applications.

You can read more about the use cases of Proof of Humanity [here](https://docs.kleros.io/products/proof-of-humanity/..#proof-of-humanity-use-cases).

## How do I use the Proof of Humanity registry?

To use the Proof of Humanity registry, we recommend following our comprehensive [tutorial](https://docs.kleros.io/products/proof-of-humanity/proof-of-humanity-tutorial), which guides you through the registration process step-by-step. It's important to read the tutorial first to ensure you understand the requirements and process. Additionally, please review the [Registry Policy ](https://cdn.kleros.link/ipfs/QmcEvNrofibGt1MQSCk7G1fFboiMyfHoYyns4En4kWG5hU)before applying to make sure you comply with all guidelines.

## Can I, as a single individual, have more than one identity submitted to Proof of Humanity?

No, you can’t. As a single individual, you are only allowed to have one profile submitted to the Proof of Humanity registry. Multiple accounts are not permitted as they constitute a Sybil attack. A Sybil attack involves creating multiple fake identities to manipulate the system. Individuals who attempt to create multiple accounts will be identified as Sybils and will be removed from the registry.

Please review the [Registry Policy](https://cdn.kleros.link/ipfs/QmcEvNrofibGt1MQSCk7G1fFboiMyfHoYyns4En4kWG5hU) before applying to make sure you comply with all guidelines.

## Which wallet address should I use to register in Proof of Humanity?

The wallet address you use to submit your profile will be publicly linked to your identity. If you prefer not to link your wallet holdings and transaction history to your identity, we recommend using a new wallet address funded from a crypto exchange.

## Which phases will my profile go through before being registered?

<figure><img src="https://3167298399-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LPbPWuMtwBOvW0iuxyw%2Fuploads%2FqzboUGmE3EYMJTsJMMVD%2FNew%20profile%20(1).png?alt=media&#x26;token=1f01e83f-a240-4aa5-90b7-712854acfffe" alt=""><figcaption><p>Flowchart for Registering a New Profile</p></figcaption></figure>

Once you submit your profile, it will enter the '<mark style="color:purple;">Vouching Phase</mark>' until someone vouches for you.

After getting at least one vouch and paying the full submitter's deposit, your profile will move to the '<mark style="color:blue;">Pending Claim</mark>' phase. During this phase, anyone can challenge your profile for 3.5 days if they believe you are not a real human or if it violates the [Registry Policy](https://cdn.kleros.link/ipfs/QmcEvNrofibGt1MQSCk7G1fFboiMyfHoYyns4En4kWG5hU)<mark style="color:yellow;">.</mark>

If your profile isn’t challenged or if any challenges are unsuccessful, your profile will be in the '<mark style="color:green;">Resolved Claim</mark>' status, meaning you are successfully registered in the Proof of Humanity registry.

📌 Incorrect submissions will result in a profile challenge. In case of a profile challenge, here's the process:

<figure><img src="https://3167298399-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LPbPWuMtwBOvW0iuxyw%2Fuploads%2Fi6ZdIENkoiEY5claxMsF%2FChallenge%20a%20Pending%20Claim.png?alt=media&#x26;token=2fcf55d6-35ae-4006-9042-f3bc4f3978f2" alt=""><figcaption><p>Flowchart for Challenging a Profile</p></figcaption></figure>

If your profile is challenged, it will either go back to the '<mark style="color:blue;">Pending Claim</mark>' phase or be 'Withdrawn,' depending on the ruling of the Kleros Court.<br>

📌 Once registered or in the '*<mark style="color:green;">Resolved Claim</mark>*', your profile can either:

* expire after a year (if you don’t renew or reapply). The renewal period starts one month before the profile expires.

<figure><img src="https://3167298399-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LPbPWuMtwBOvW0iuxyw%2Fuploads%2F2n28XLOTVKIpItcbrQ2i%2FReapply%20profile.png?alt=media&#x26;token=7ce543b6-3f23-42cc-ae8d-0f18d6d0b6fa" alt=""><figcaption><p>Flowchart for Profile Renewal</p></figcaption></figure>

* or get revoked due to a malicious or incorrect submission, or if you want to make changes to your profile. Making changes to your profile requires you to revoke your existing profile and resubmit a new one.

<figure><img src="https://3167298399-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LPbPWuMtwBOvW0iuxyw%2Fuploads%2F4k8fSKhgaIDplVPBvgzV%2FRevoke%20profile.png?alt=media&#x26;token=d210bb8c-6e71-4087-8ca8-d6643667d2e5" alt=""><figcaption><p>Flowchart for Revoking a Profile</p></figcaption></figure>

If your profile is 'Expired', '<mark style="color:red;">Revoked</mark>' or about to expire, you can reapply for submission, bringing you back to the '<mark style="color:purple;">Vouching Phase</mark>'.

## Why should I vouch for someone? What's in it for me?

Vouching for someone is a benevolent act in order to help people you know be accepted into the registry. Be careful with whom you vouch for. If by mistake (or excess of trust) you vouch for a malicious user, you will be penalized.

## What happens if I vouch for a malicious user?

If a submission is challenged and rejected for 'Sybil attack' or 'Identity theft' reasons, all people who had vouched for the rejected profile get *removed* from the registry. This allows to weed out malicious attackers who vouch for sybils or duplicate accounts. It also means you have to be careful when vouching: make sure you know the person in real life and that it is not a duplicate.

## How many people can I vouch for?

You can vouch for as many people as you like. However, your vouch will only count for one person at a time, in the order they were given. A user's vouch can only be used for one submission at a time on a “first come, first served” basis.

For example, if user A is registered and vouches for user B, user B will move to the '<mark style="color:blue;">Pending Claim</mark>' phase. If A then vouches for user C, C will remain in the '<mark style="color:purple;">Vouching Phase</mark>' until B is registered or in the  'Resolved Claim', after which C will move to the '<mark style="color:blue;">Pending Claim</mark>' phase.

## Can I remove a vouch?

You can remove your vouch at any time prior to the '<mark style="color:blue;">Pending Claim</mark>' phase by going to the vouched person's profile and clicking on '<mark style="color:orange;">Remove Vouch</mark>'.

## When does my deposit get returned?

Your deposit will be returned to the funding address shortly after you move to '<mark style="color:green;">Ve</mark><mark style="color:green;">rified Human</mark>' status.

## How long does the registration last?

Registrations have a duration of 1 year. This means that users need to periodically reapply to the registry. The purpose of the limited registration period is to remove people who die and malicious submissions which might have made it into the list. Conditions to reapply are similar to the original application.

You can reapply before the current registration period ends (1 month before expiry) in order to avoid spending some time unregistered. Users reapplying (such that they have the required vouching and deposit) before their registration ends are considered registered for the entire period of their new application.

## What rules should I follow to submit a proper profile or to remove an incorrect one?

Check the [Registry Policy](https://cdn.kleros.link/ipfs/QmcEvNrofibGt1MQSCk7G1fFboiMyfHoYyns4En4kWG5hU) to obtain all the detailed conditions for a profile to be accepted or rejected from the registry.

## Can I request to remove someone else profile from the registry?

A request to remove a registered submission from the list can be made at any time by submitting a deposit and a reason for removal.

## Can I remove my profile and submit it again because I want to change something about it? How do I proceed?

### **I. If your profile is still in '***<mark style="color:purple;">**Vouching Phase'**</mark>*

If your profile is still in the '<mark style="color:purple;">Vouching Phase</mark>' and you want to change something, you can do so by withdrawing your current submission and resubmitting with a new and updated profile.

Check our tutorial on [how to remove or withdraw a profile](https://docs.kleros.io/products/proof-of-humanity/proof-humanity-2.0-tutorial-remove-and-challenge).

### **II. If your profile is already registered or in the '***<mark style="color:green;">**Resolved Claim**</mark>***'**&#x20;

First, you need to remove your own existing profile and then either reapply using the same wallet address or submit with another address for a new registration. In order to remove your old registered profile, you need to go to your registered profile page and click on the '<mark style="color:orange;">Revoke</mark>' button and then provide evidence that you are indeed the submitter. Check out our [tutorial](https://docs.kleros.io/products/proof-of-humanity/proof-humanity-2.0-tutorial-remove-and-challenge).

{% hint style="success" %}
***Example 1.\*\*\*\*&#x20;**<mark style="color:orange;">**Send a removal request from the same address as the submitter.**</mark>*

**Evidence Name**: Self-removal of submission.

**Evidence Description**: I am the submitter as proven by my address and I want to remove this submission
{% endhint %}

{% hint style="success" %}
***Example 2:\*\*\*\*&#x20;**<mark style="color:orange;">**Send a removal request from a different address than the submitter.**</mark>*

**Evidence Name**: Self-removal of submission.

**Evidence Description**: I am the submitter and I want to remove this submission. The video attached is a recording of myself saying the sentence “I want to remove my own submission from the Proof of Humanity registry.”
{% endhint %}

{% hint style="success" %}
***Example 3:\*\*\*\*&#x20;**<mark style="color:orange;">**Send a removal request to remove a malicious or incorrect submission.**</mark>*

**Evidence Name**: Removal of deepfake submission.

**Evidence Description**: I have analyzed the video of the submitter and the reproducible report attached in this evidence proves that it is a deepfake.
{% endhint %}

## Why did the registry start with some users already registered in it?

Since we require user vouching for new members, we had to start with an initial set of trusted and manually curated users. Those registered through the seeding event will still have to periodically renew their registration like any other user.

## Why can’t I display my ENS in my submission video?

In order to reduce the attack surface at launch, we decided against allowing to display or use ENS. A user could lose control of its ENS, forget to renew it, or be outbid.

## As deepfakes get better, will challengers be able to keep up technologically to defend against this?

Improvements in machine learning are likely to affect the effectiveness of both deepfake creation and deepfake detection algorithms. If algorithms manage to produce deepfakes not detectable by other algorithms, other evidence would need to be required. This can be decided through Kleros governance process.

## What if my religion forbids me from showing my face? What if I am physically unable to speak?

Internal features of the face are the most important for face recognition and removing the requirement to pronounce the sentence would decrease the security of the system (speech analysis can be used to detect multiple registrations). For the moment, these edge cases do not allow the person to be registered. If you have a proposal that would enable the secure registration of this edge case (and others), you can write a about it in the PoH forum and submit it through the governance process.

## What if I have an identical twin that also wants to be registered?

While most people have a hard time distinguishing twins, identical twins aren't actually identical and can be distinguished by skilled individuals. Moreover, facial recognition algorithms tend to do a better job than humans distinguishing between twins. This means a twin submission could be challenged but the twin could probably easily provide evidence that he is a twin to win the dispute.