# UUID Key

Generates UUIDs on [primary key columns](https://docs.tonic.ai/app/generation/generators/generator-types/primary-key-generators).

All foreign key columns that reference the configured column automatically have their UUID values masked.

## Characteristics <a href="#uuid-key-characteristics" id="uuid-key-characteristics"></a>

<table data-header-hidden><thead><tr><th valign="top"></th><th valign="top"></th></tr></thead><tbody><tr><td valign="top"><strong>Consistency</strong></td><td valign="top">Yes, can be made self-consistent.</td></tr><tr><td valign="top"><strong>Linking</strong></td><td valign="top">No, cannot be linked.</td></tr><tr><td valign="top"><strong>Differential privacy</strong></td><td valign="top">No</td></tr><tr><td valign="top"><strong>Data-free</strong></td><td valign="top">No</td></tr><tr><td valign="top"><strong>Allowed for primary keys</strong></td><td valign="top">Yes</td></tr><tr><td valign="top"><strong>Allowed for unique columns</strong></td><td valign="top">Yes</td></tr><tr><td valign="top"><strong>Uses format-preserving encryption (FPE)</strong></td><td valign="top">Yes</td></tr><tr><td valign="top"><strong>Privacy ranking</strong></td><td valign="top"><ul><li>3 if not consistent</li><li>4 if consistent</li></ul></td></tr><tr><td valign="top"><strong>Generator ID (for the API)</strong></td><td valign="top"><a href="../../../api/quick-start-guide/tonic-api-generator-assignment/generator-api-reference/generator-api-ref-uuid-key"><code>UuidPkGenerator</code></a></td></tr></tbody></table>

## How to configure <a href="#uuid-key-configure" id="uuid-key-configure"></a>

To configure the generator:

1. To preserve the version and variant bits from the source UUID in the output value, toggle **Preserve Version and Variant** to the on position.
2. Toggle the **Consistency** setting to indicate whether to make the generator self-consistent.\
   \
   By default, the generator is not consistent.
3. If [Structural data encryption](https://docs.tonic.ai/app/generation/generators-assign-config/generators-data-encryption-config) is enabled, then to use it for this column, in the advanced options section, toggle **Use data encryption process** to the on position.