# Auto-classify data assets {% embed url="" %} Using the auto-classification workflow for Sensitive Content Pattern. {% endembed %} Adding classifications manually might be a time-consuming task, especially if it's your first time on decube. Instead, you can opt to add it via our auto-classification workflow via the Policy rules, where you can set up keywords or via regex to detect matching asset names across multiple data sources.

Example of a rule that has been set up to detect the address column across multiple data sources.

### Set up your policy rules From any classification policies page, you can click on `Set up new rule` to access the new rule setup workflow. 1. Select the data sources to apply the rules. 2. Select the rule type. You can choose either to input a keyword or a regex to match strictly or approximately. * Optionally, if we detect new assets that have been added to your data sources, we can also add the classification automatically if you check the checkbox for `Auto-add new assets to this rule`. {% hint style="warning" %} Note that the regex expression has to be written in ElasticSearch syntax. Information on what are valid regex expressions can be found [here](https://www.elastic.co/docs/reference/query-languages/query-dsl/regexp-syntax). {% endhint %} 3. Click on `Fetch assets`. All assets that match according to your rule type will be shown. 4. Select one of the several masking types to be applied. This will take effect in the [Preview](/catalog/preview-sample-data.md) section where dynamic masking is applied. The creation, modification, and deletion of a rule will require an approval workflow before it is reflected in your organization. You can read more on the [approval workflow](https://github.com/DecubeIO/decube-docs/blob/public/governance/auto-classify-data-assets/broken-reference/README.md) here.

Setting up a new rule is a simple and straightforward process to fetch all relevant assets.

### Masking type - Hierarchy for masking When multiple classification policies are applied to the column, the masking type selected if they are different, will follow a certain hierarchy to be shown to the user, with the highest priority masking type applied. You can view the below masking type sorted from highest to lowest priority: * SHA-256 * First four characters * Last four characters * Email masking (eg. \*\*\*\*\*\*\*\*@domain.com) * Hash\* (eg. \*\*\*\*\*) * Nullify --- # Agent Instructions: 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://docs.decube.io/governance/auto-classify-data-assets.md?ask= ``` 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.