Date: Sat, 13 Jan 2018 01:11:12 -0500
From: Peter Todd <pete@petertodd.org>
To: nullius <nullius@nym.zone>,
	Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Message-ID: <20180113061112.GA14217@savin.petertodd.org>
References: <CAAS2fgR-or=zksQ929Muvgr=sgzNSugGp669ZWYC6YkvEG=H5w@mail.gmail.com>
	<ae570ccf-3a2c-a11c-57fa-6dad78cfb1a5@satoshilabs.com>
	<CAAS2fgRQvpa8VXE8YAYSfugDvCu=1+5ANsGk1V_OXtHPGD=Ltw@mail.gmail.com>
	<vJsDz9YdeNQQ_PZRf5HP1W0FmcWyKHIuwN9QeNgN-WXCdQcRmXLtkQ3wfTO7YUCgG6AFgOkKeU6fdsGTKkGcnk-_OOY_jyNlfWkFQ31d2ZU=@protonmail.com>
	<20180109011335.GA22039@savin.petertodd.org>
	<274aad5c-4573-2fdd-f8b0-c6c2d662ab7c@gibsonic.org>
	<20180112095058.GA9175@savin.petertodd.org>
	<3b45c17a256326b6b183587d9d15690c@nym.zone>
	<PS2P216MB01793245561CC130C6FEEC9A9D140@PS2P216MB0179.KORP216.PROD.OUTLOOK.COM>
	<bd9283ec34396d769a84664ac5ae9206@nym.zone>
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User-Agent: Mutt/1.5.23 (2014-03-12)
Subject: Re: [bitcoin-dev] Plausible Deniability (Re: Satoshilabs secret
 shared private key scheme)
Precedence: list


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On Sat, Jan 13, 2018 at 03:44:03AM +0000, nullius via bitcoin-dev wrote:
> (I think that next, I may start writing my disks with headers for LUKS,
> which I do not use...)
>=20
> Whereupon, I challenge plausible deniability designers to `dd` a 6TB disk
> with pseudorandom bytes, then try walking it across the U.S. border until=
 it
> gets searched.  What could possibly go wrong?  Should you be ordered to
> decrypt it, the disk *could* be *plausibly* filled with pseudorandom byte=
s;
> and you would not be committing the crime of lying to an officer, when you
> truly state that in fact, it *is* filled with pseudorandom bytes.

It's very common for disks to be filled with pseudorandom data; this is not
suspicious at all. For example:

1) An encrypted partition that is filled, and later reformatted, will be le=
ft
full of random bytes. Even if you give border security your passphrase, the
unused space in the encrypted partition will be random data. (an exception
being most - but not all! - SSD's where TRIM has been used)

2) Modern drives (SSD and HD) often implement fast secure erasure with
encryption, which means that the actual data stored to disk or FLASH is
*always* encrypted. If such a drive is wiped, the encryption keys are repla=
ced,
which means whatever data was stored becomes random noise (the encrypted da=
ta
is usually not authenticated). This also means that such drives can arrive =
=66rom
the factory filled with random noise.

3) Software disk encryption schemes have the same property: reformatting
results in a drive filled with random noise.

The latter is particularly interesting with LUKS, as you can do all kinds of
things like erase the drive with luksErase, while keeping a backup of the L=
UKS
header elsewhere.

--=20
https://petertodd.org 'peter'[:-1]@petertodd.org

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