> 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/piv-1/getting-started/2.-pins/about.md).

# About

### <mark style="color:blue;">PIN</mark>

<mark style="color:yellow;">`P`</mark>`ersonal`` `<mark style="color:yellow;">`I`</mark>`dentification`` `<mark style="color:yellow;">`N`</mark>`umber`

<mark style="color:red;">`default:`</mark><mark style="color:red;">` `</mark><mark style="color:red;">**`123456`**</mark>

The PIN is used during normal operation to authorize an action such as creating a digital signature for any of the loaded certificates. Entering an incorrect PIN three times consecutively will cause the PIN to become blocked, rendering the PIV features unusable. The PIN must be at least 6 characters, and can contain any characters, though for cross-platform portability it is recommended to only use decimal digits. There is a limit of 8 bytes for a PIN, which allows for up to 8 ASCII characters

### <mark style="color:blue;">PUK</mark>

<mark style="color:yellow;">`P`</mark>`IN`` `<mark style="color:yellow;">`U`</mark>`nblocking`` `<mark style="color:yellow;">`K`</mark>`ey`

<mark style="color:red;">`default:`</mark><mark style="color:red;">` `</mark><mark style="color:red;">**`12345678`**</mark>

The PUK is used to reset the PIN if ever lost or blocked after the max number of incorrect attempts. Setting a PUK is optional. If you use your PIN as the Management Key, the PUK is disabled for technical reasons. The requirements and restrictions of the PUK are the same as for the PIN (see above). If PIN complexity is enforced, the same rules are applied to the PUK. If the PUK ever becomes blocked, either by deliberately choosing to block it or by giving the wrong PUK value 3 times, it can only be unblocked by performing a complete reset. A complete reset wipes the entire PIV module. You will lose all PIV keys stored on your Yubikey, and your PINs will be reset to their default values.

### <mark style="color:blue;">MANAGEMENT KEY</mark>

<mark style="color:red;">`default:`</mark><mark style="color:red;">` `</mark><mark style="color:red;">**`010203040506070801020304050607080102030405060708`**</mark>

The PIV management key will be asked for when you perform tasks on your yubikey such as generating new PIV keys. You won't need this most of the time, but it will be required when performing management actions on your yubikey itself.


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