> For the complete documentation index, see [llms.txt](https://yubico.gitbook.io/yubikey5/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yubico.gitbook.io/yubikey5/guides/understanding-pins.md).

# Understanding PINs

Review the various PINs below and ensure you have the correct device:

<table><thead><tr><th></th><th width="97">PINs</th><th width="163">Interfaces</th><th>Color</th></tr></thead><tbody><tr><td><img src="/files/cx3UyzbMaa2qyyOJ3lWy" alt=""> <a href="#security-series"><strong>Security Series</strong></a></td><td>1</td><td>FIDO2 (1)</td><td>Blue<br>As of 2023, they now come in black.</td></tr><tr><td><img src="/files/cx3UyzbMaa2qyyOJ3lWy" alt=""> <a href="#yubikey-5-series"><strong>5 Series</strong></a></td><td>5</td><td><p>FIDO2 (1)</p><p>GPG (2)</p><p>PIV (2)</p></td><td>Black</td></tr></tbody></table>

If you are unsure if you have the Security Series device, or the 5 Series. Look at the back of the device near the USB PINs.

<figure><img src="/files/q3SQUobxx9QLhLG1YMJj" alt=""><figcaption><p>The back of a Yubikey 5 NFC Series security device</p></figcaption></figure>

<table><thead><tr><th width="322">Device</th><th>Printed On Back of Key</th></tr></thead><tbody><tr><td><img src="/files/cx3UyzbMaa2qyyOJ3lWy" alt=""> <a href="#security-series"><strong>Security Series</strong></a></td><td>"FIDO"</td></tr><tr><td><img src="/files/cx3UyzbMaa2qyyOJ3lWy" alt=""> <a href="#yubikey-5-series"><strong>5 NFC Series</strong></a></td><td>8-9 digit number<br>Barcode</td></tr><tr><td><img src="/files/cx3UyzbMaa2qyyOJ3lWy" alt=""> <a href="#yubikey-5-series"><strong>5 FIPS Series</strong></a></td><td>"FIPS"<br>8-9 digit number<br>Barcode</td></tr></tbody></table>

{% hint style="info" %}
As of 2023, Yubico has announced an updated version of the Security Series keys which are now black and look almost identical to the Yubikey 5 Series keys.

\
Prior to 2023, the Security Series keys were blue.

\
![](/files/cx3UyzbMaa2qyyOJ3lWy) [For more information, view the official page.](https://www.yubico.com/products/security-key/)
{% endhint %}

## <mark style="color:red;">Security Series</mark>

<figure><img src="/files/KNO7p2fOxcZPKFhy7Fqw" alt=""><figcaption></figcaption></figure>

The ![](/files/cx3UyzbMaa2qyyOJ3lWy) [**Yubikey Security Series**](https://www.yubico.com/products/security-key/) is Yubico's more affordable model security device which comes in at nearly half the price of the Yubikey 5. However, it comes with less features, and is primarily for FIDO2 / Webauthn. This device only has <mark style="color:red;">**1 PIN**</mark> associated to the FIDO2 module. These keys do not include interfaces such as GPG, PIV, etc.

<table><thead><tr><th width="188.33333333333331">Interface</th><th width="114">PINs</th><th>Brief Description</th></tr></thead><tbody><tr><td><a href="/pages/WsqVVbJoSD13vAtTHKUq"><img src="/files/cx3UyzbMaa2qyyOJ3lWy" alt=""> </a><a href="/pages/WsqVVbJoSD13vAtTHKUq"><strong>FIDO2</strong></a></td><td>1 PIN</td><td>Authenticate with websites such as Microsoft, Google, Bitwarden, PayPal, etc.</td></tr></tbody></table>

## <mark style="color:red;">Yubikey 5 Series</mark>

<figure><img src="/files/jNPBq2sulbfs1s34tHQW" alt=""><figcaption></figcaption></figure>

The ![](/files/cx3UyzbMaa2qyyOJ3lWy) [**Yubikey 5 Series**](/yubikey5/gpg/introduction.md) has several technologies (or interfaces) included. Each of those technologies do different things so that you have a wide variety of options on how to use your Yubikey.

In total, your Yubikey 5 has <mark style="color:yellow;">**5**</mark> <mark style="color:yellow;">**PINs**</mark>, <mark style="color:red;">**1 Management Key**</mark>, and <mark style="color:green;">**1 Reset Code**</mark>.

<table><thead><tr><th width="165">Interface</th><th width="202">PINs</th><th>Brief Description</th></tr></thead><tbody><tr><td><img src="/files/cx3UyzbMaa2qyyOJ3lWy" alt=""> <a href="/pages/WsqVVbJoSD13vAtTHKUq"><strong>FIDO2</strong></a></td><td>1 PIN</td><td>Authenticate with websites such as Microsoft, Google, Bitwarden, PayPal, etc.<br><br><mark style="color:red;"><strong>No default PIN</strong></mark><br>This PIN is set the first time you link your Yubikey to a website or Windows.<br></td></tr><tr><td><img src="/files/cx3UyzbMaa2qyyOJ3lWy" alt=""> <a href="/pages/3WeZ9UASXbEiOtBrspnn"><strong>GPG</strong></a></td><td>2 PINs<br>1 Reset Code</td><td><br>Allows you to do tasks such as encrypting / decrypting files, sign Github commits, and also supports SSH.<br><br><mark style="color:red;"><strong>Defaults</strong></mark><br><code>User PIN:</code> 123456<br><code>Admin PIN:</code> 12345678<br></td></tr><tr><td><img src="/files/cx3UyzbMaa2qyyOJ3lWy" alt=""> <a href="/pages/3wtrr2HTRSqMOINIIlhm"><strong>PIV</strong></a></td><td>2 PINs<br>1 Management Key</td><td><br>Do things like import x509 certificates / keypairs to your Yubikey. Can be used for services such as Bitlocker, Veracrypt, EFS, SSH, etc.<br><br><mark style="color:red;"><strong>Defaults</strong></mark><br><code>PIN:</code> 123456<br><code>PUK:</code> 12345678<br></td></tr></tbody></table>

If you have no need for things like GPG or PIV, you may never even cross paths with these PINs. You might only want to just sign into websites, and if so, then you'll only ever be asked for your FIDO2 PIN.

{% hint style="info" %}
Automatically assume that if you've never messed with GPG or PIV on your Yubikey and your device asks for a PIN, it will be asking for your FIDO2 pin.
{% endhint %}

Let's break down the different interface PINs. Click an interface below to learn about each one:

|                                                                                            |
| ------------------------------------------------------------------------------------------ |
| ![](/files/cx3UyzbMaa2qyyOJ3lWy) [**FIDO2**](/yubikey5/guides/understanding-pins/fido2.md) |
| ![](/files/cx3UyzbMaa2qyyOJ3lWy) [**GPG**](/yubikey5/guides/understanding-pins/gpg.md)     |
| ![](/files/cx3UyzbMaa2qyyOJ3lWy) [**PIV**](/yubikey5/guides/understanding-pins/piv.md#piv) |


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://yubico.gitbook.io/yubikey5/guides/understanding-pins.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.