A scene in the documentary CitizenFour showed Snowden using a blanket to cover his head and the laptop screen. When asked by Greenwald about this, he answered affirmatively, but I couldn't really understand what Greenwald meant/said.

What was Snowden mitigating by that action?

  • 3
    I haven't seen the movie, so am not making this an answer, but I believe there was a reference to this in No Place To Hide describing that he did it because of concern for cameras in the vicinity. Placing a blanket over your head and the computer would seem to mitigate that threat fairly well with only moderate inconvenience.
    – user
    Commented Feb 23, 2015 at 22:02

2 Answers 2


The Background

The general situation was Snowden entering his password at that time, and he wanted to mitigate visual surveillance, let it be by observation or (hidden) cameras. It seems, Snowden didn't trust anything but his own laptop (if at all) during these first day(s) of contact with the journalists.

He also offered the blanket to the others in the room when they were entering their credentials into their laptops, but they refused, probably regarding this as being overcautious.

The Exact Scene

Snowden pulling blanket over his head

(Original footage from Citizenfour by Laura Poitras)

37:35 [Snowden pulling blanket over his head/laptop]
37:44 Greenwald: Is that about the posibility of...
37:47 Snowden [still under blanket, interrupts] visual, yeah visual collection
37:50 [Greenwald looking around the room, seems not rather sure what to think and say]
37:55 Greenwald: I don't think at this point there is anything in this regard that will shock us. [laughter in room]

Some general chit-chat about never leaving devices alone any more follows.

  • 2
    Still, using some advanced audio software, from the typing sound of the pressed keys, deducing from echo, reverb, comparing with the sound of a keyboard of an identical laptop, you could determine their coordinates in space. You can also analyse the movement of muscles of Snowden's arms and extrapolate up to its fingers' location and movement. Commented Jan 15, 2016 at 11:35
  • 42
    "He also offered the blanket to the others in the room when they were entering their credentials into their laptops, but they refused, probably regarding this as being overcautious." Or they were afraid it was a tracking blanket. Commented Jan 15, 2016 at 18:44
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    @PyRulez A lead-lined tracking blanket.
    – wizzwizz4
    Commented Jan 15, 2016 at 18:46
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    As per this meta question, I'm trying to change the included image URI to protocol relative, but I can't edit less than 6 chars. Could you do that instead? Should have //i.sstatic.net/bDeLe.png instead of i.sstatic.net/bDeLe.png Commented Jan 16, 2016 at 10:37
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    Done; seems something that should be handled by a script for all i.stack.imgur.com URIs. Or even better, just enforce HTTPs for all of them...
    – Jens Erat
    Commented Jan 16, 2016 at 10:41

He was using the blanket to fool visual recording devices attempting to steal his password, even though with modern technology x-ray or thermal imaging could effectively 'see through' the blanket.

  • 6
    very interesting, upvoted... but could you add a reference to your claim that "seeing through" is nowadays feasible? Commented Jan 16, 2016 at 14:06
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    I can see how IR has a chance to detect something if the wrong kind of blanket is used. No idea how you want to use XRay, as it requires an emitter as well as a receiver.
    – Peter
    Commented Jan 17, 2016 at 11:40
  • en.wikipedia.org/wiki/Thermographic_camera
    – kevin
    Commented Jan 22, 2016 at 23:20
  • 3
    @Peter They could be in opposite walls, perhaps? Or in the two neighbor rooms in the hotel?
    – Rodrigo
    Commented Feb 26, 2016 at 14:18
  • I think assumption was that NSA or other organizations were not aware of the location of Snowden so he only needed to be safe against hidden regular cameras, not targeted attacks. High resolution thermal imaging or x-ray devices were way too expensive in 2013 to use as spy cameras without knowing that high value target were to enter the space. Commented Feb 1 at 11:31

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