Re: [Tails-dev] The authenticity/genuineness of an usb TAILS…

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Author: intrigeri
Date:  
To: The Tails public development discussion list
Subject: Re: [Tails-dev] The authenticity/genuineness of an usb TAILS-device
hi,

Daniel Kahn Gillmor wrote (06 Nov 2014 16:14:43 GMT) :
> On 11/06/2014 09:49 AM, intrigeri wrote:
>> I'm not sure if isohybrid (assuming the very same binary thereof)
>> has reproducible behaviour. dd certainly has. Just try? :)


> dd won't have "reproducible behavior" across usb sticks if you're
> looking at the full block devices for two USB sticks of different sizes


Sure.

> if you were just comparing the number of bytes that matched the size of
> the .iso, it'd be ok, but most folks probably don't want to do:


> cmp <(dd if=/dev/sdx bs=1M count=$SZ) <(dd if=/dev/sdy bs=1M count=$SZ)


> where $SZ is the size of the iso in MiB.


Sure. OTOH, if someone wanted to support the following usecase, they
could provide a script that does it all:

  1. I have a Tails USB stick installed with isohybrid+dd, that I'm
     not sure about.
  2. I have a Tails ISO that I believe to be genuine.
  3. I want to check that what's on the USB stick matches this ISO.


However, reinstalling from the genuine ISO is probably simpler in
most cases.

Cheers,
--
intrigeri