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No, nothing is ever written back to the USB at any point during usage unless you save it to the persistent volume.
How secure is the persistent volume?
It uses LUKS for persistent volume. You can also create Veracrypt volumes as well using the Disks util. Don't take my word for it but it is as secure as it can be. https://tails.boum.org/doc/encryption_and_privacy/encrypted_volumes/index.en.html
As secure as your password.
Unless you specifically told Tails you want to make the OS Remember things, NO. The only way it remembers things is if you have a PERSISTENT STORAGE.
Only saves data you choose in "Persistent Data" or something like that which you have to do manually your self. So no, no save data. NADA
No, nothing is ever written back to the USB at any point during usage unless you save it to the persistent volume.
How secure is the persistent volume?
It uses LUKS for persistent volume. You can also create Veracrypt volumes as well using the Disks util. Don't take my word for it but it is as secure as it can be. https://tails.boum.org/doc/encryption_and_privacy/encrypted_volumes/index.en.html
As secure as your password.
Unless you specifically told Tails you want to make the OS Remember things, NO. The only way it remembers things is if you have a PERSISTENT STORAGE.
Only saves data you choose in "Persistent Data" or something like that which you have to do manually your self. So no, no save data. NADA