> For the complete documentation index, see [llms.txt](https://docs.zipwire.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zipwire.io/fundamentals/security/attestations/the-istwentyone-attestation-purpose-and-limitations.md).

# The "IsTwentyOne" Attestation: Purpose and Limitations

## Overview

The "IsTwentyOne" attestation is a statement of fact that confirms a wallet holder is at least 21 years old. This attestation is useful for platforms and services that require age verification, such as alcohol sales, gambling services, or other age-restricted activities.

## How It Works

The process follows the standard attestation workflow:

1. **Wallet Connection**: Connect your Ethereum wallet to Zipwire
2. **Age Verification**: Complete a Yoti ID check that verifies your date of birth
3. **Age Calculation**: Zipwire calculates your age from the verified date of birth
4. **Attestation Issuance**: If you're 21 or older, claim the "IsTwentyOne" attestation
5. **Blockchain Recording**: The attestation is recorded on the Base blockchain

{% content-ref url="/pages/TfrUK5pGnJhSthL5TLjm" %}
[Attestations](/fundamentals/security/attestations.md)
{% endcontent-ref %}

## Privacy Features

* The attestation only confirms the age threshold (21+) without revealing your exact date of birth
* No personal data is stored on the blockchain
* The attestation can be verified without exposing additional personal information

## How to Get IsTwentyOne Attestations

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[Attestations](/fundamentals/security/attestations.md)
{% endcontent-ref %}

You can obtain IsTwentyOne attestations through:

* **Self-service**: Use [Zipwire Attest](/zipwire-attest/zipwire-attest.md) for independent registration
* **Business integration**: Use [Zipwire Collect](https://github.com/zipwireapp/gbk-tz-docs/blob/main/zipwire-collect/README.md) when businesses include ID checks

## Use Cases

* **Alcohol sales** - Verify customers are 21 or older
* **Gambling platforms** - Ensure users meet age requirements
* **Adult content** - Age-gate access to mature content
* **Financial services** - Some services require users to be 21+

## Limitations

* **Age Threshold Only**: Confirms you're 21+, not your exact age
* **Transfer Vulnerability**: If a wallet is sold or stolen, the attestation remains
* **Age Revealing**: Unlike some attestations, this does reveal that you're at least 21
* **Permanent Record**: Once issued, the attestation is permanent on the blockchain

## Best Practices

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[Attestations & Privacy: Timing Your Claims & Data Deletion](/fundamentals/security/attestations-privacy-timing-data-deletion.md)
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* **Consider timing**: Space out age attestation claims to avoid linking wallet addresses
* **Understand permanence**: Age attestations are permanent once issued
* **Use appropriately**: Only require age attestations when necessary for your service

## Comparison to Other Attestations

* **IsAHuman**: Confirms the wallet belongs to a real person (no age information)
* **IsTwentyOne**: Confirms the user is at least 21 years old
* **Private Data Attestations**: Allow selective disclosure of specific age information

{% content-ref url="/pages/uKh9zVF06YZtly50dFyc" %}
[The "IsAHuman" Attestation: Purpose and Limitations](/fundamentals/security/attestations/the-isahuman-attestation-purpose-and-limitations.md)
{% endcontent-ref %}

{% content-ref url="/pages/UgJwIIVTljJ5n8pkWDKi" %}
[The "Private Data" Attestation: Merkle Roots](/fundamentals/security/attestations/the-private-data-attestation-merkle-roots.md)
{% endcontent-ref %}