<span class="application">[Tor Browser](https://www.torproject.org)</span> is a web browser based on [Mozilla Firefox](https://www.mozilla.org/firefox/) but configured to protect your privacy.
Security vulnerabilities in JavaScript have been used to [deanonymize Tor Browser in the past](https://arstechnica.com/information-technology/2013/08/attackers-wield-firefox-exploit-to-uncloak-anonymous-tor-users/).
<p>To prevent Tails from running out of memory and crashing, download very big files to the <em>Persistent/Tor Browser</em> folder. All the files that you download outside of the Persistent Storage are stored in memory (RAM), which is more limited.</p>
For example, here is how the browser looks when we try to log in to an email account at [riseup.net](https://riseup.net/), using their [webmail interface](https://mail.riseup.net/):
Notice the padlock icon on the left of the address bar saying "mail.riseup.net".Notice also the address beginning with "https://" (instead of "http://"). These are the indicators that an encrypted connection using [[!wikipedia HTTPS]] is being used.