Looking in to Veracrypt to use it in some spaces, but more for encrypting an entire USB partition. I was curious as to how the key would be passed though. I don't want someone to be able to intercept it if it gets passed via the USB port. Any clue as to how Veracrypt handles this? Curious to learn how Veracrypt handles this.

2 Answers 2


I'm not quite sure what you mean with "does the key it get passed over USB". I'm assuming that you're asking whether the volume encryption key gets passed from your external USB storage device to your CPU, or vice versa.

The answer to that question is yes.

The reason for this is that your passphrase which you use to unlock the volume is not actually the encryption key for the data. The encryption key is stored on the volume, but it is encrypted with your passphrase (after it undergoes key stretching etc).

This is why you can change your passphrase without re-encrypting the whole volume - you basically just re-encrypt the encryption key with your new passphrase.

So, if you think about it, since the actual encryption key is stored in the VeraCrypt volume header, and the volume header is sitting on the USB storage device, obviously there must be a moment when the encryption key - in encrypted form - is moved from the USB storage device to the CPU.

I don't see a security problem with this, though.

OTOH, if you were asking whether your passphrase to unlock the volume gets passed to the USB storage device, then I'd agree with Thomas that no, it isn't passed.


If if were passed over USB, that would mean the USB disk could do the decryption for you. But that's not the case. You can use Truecrypt / Veracrypt on any hard disk, even if it does not have crypto hardware built-in.

So: no, the key won't be passed over USB.

However, if you use a USB keyboard, the password of the key will be transferred over USB.

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