# Files

> [HTML Version](360024799491.html)

In this workspace, you can restrict the list of available file formats for upload.

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Only users included in the [Administrators](360006871932.md#administrators) group can change file settings**.**

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Available file formats for uploading

You can restrict file uploads to only specific formats by specifying their extensions and signatures for unambiguous format identification. To do this:

1. In the **Available File Extensions for Upload** section, enable the restriction and click **Save**.  
**(files_settings02.png)**

2. Define the list of allowed formats. To do this, click **+ Add Extension** and fill in the fields in the window that opens:  
**(files_settings03.png)**

- **File extension**. Enter the format allowed for upload.

- **Use extension only**. Enable this option if you are specifying a format that does not have a signature, such as **.txt**. The signature field will then become inactive, and you can add the format to the list.

- **First 8 bytes**. Enter up to eight bytes of the extension signature. For example, the signature for the **.png** extension is **89 50 4E 47 0D 0A 1A 0A**. An extension may have multiple signatures, such as different values for different **.pdf** versions (**PDF 1.0**, **PDF 1.1**, etc.). Specify all variants by clicking **+ Add Signature**. A list of signatures is available on [Wikipedia](https://en.wikipedia.org/wiki/List_of_file_signatures) or on specialized sites such as [Asecuritysite.com](https://asecuritysite.com/forensics/magic).