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When browsing the web, cached versions of websites are downloaded and saved for indefinite periods automatically by internet browsers. Every image and .html file associated with the website are stored in the browser's cache folders as perfect reconstructions that can be opened offline until the web cache is manually cleared.

Does the Tor browser do the same by saving cached versions of .onion sites?

Update

The answer below stipulates that Tor, by design, "must not write any information" to hard disk. However, there is a settings option in the Tor browser called Delete browsing data, which shows that Cached images and files must be deleted manually. This suggests that Tor actually does cache and write information to hard disk, and even keeps cookies since there is also an option called Cookies that have to be manually deleted as well. I am confused who is right

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The Tor Browser is designed to avoid writing any sensitive data to disk unless the user changes the default settings to enable a feature that does record sensitive data. So with the default settings, Tor Browser does not save cached versions of websites. You might find this document useful (section 4.3. Disk Avoidance): https://2019.www.torproject.org/projects/torbrowser/design/

The browser MUST NOT write any information that is derived from or that reveals browsing activity to the disk, or store it in memory beyond the duration of one browsing session, unless the user has explicitly opted to store their browsing history information to disk.

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  • whats the point of using Tails OS then if Tor won't even leave a footprint on hard drives?
    – user610620
    Commented Jan 24, 2021 at 21:09
  • Just having Tor Browser installed might be harmful to you, whereas Tails doesn't touch your hard drive at all. Tails is also for more than just web browsing. For example if you download a document and open it outside of Tor Browser (for example in evince or adobe reader), it may make an HTTP request. On Tails this request would be blocked or go through Tor, whereas on a regular OS this would leak your IP address.
    – Steve
    Commented Jan 24, 2021 at 21:16
  • should downloaded files be downloaded on a second USB while running the Tails OS session, then offloaded to a second laptop that has no way of connecting to the internet to safely open those files?
    – user610620
    Commented Jan 24, 2021 at 21:41
  • I think you should be able to safely open them in Tails, but I don't use Tails.
    – Steve
    Commented Jan 24, 2021 at 22:41
  • Your answer stipulates that Tor, by design, "must not write any information" to hard disk. However, there is a settings option in the Tor browser called Delete browsing data, which shows that Cached images and files must be deleted manually. This suggests that Tor actually does cache and write information to hard disk, and even keeps cookies since there is also an option called Cookies that have to be manually deleted as well. I am confused who is right
    – user610620
    Commented Feb 1, 2021 at 2:15

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