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References: <CAMPt2UN=ySXRP04cB+Cx3frF0u9F2yWoHCVZsvz5VG=ZEaZJCw@mail.gmail.com>
Date: Fri, 14 Mar 2014 04:19:56 +0100
Message-ID: <CA+s+GJB5bh3W1kkNQ78Xyds+o4x84eDc=OUFFb3gzZzDrEC+ag@mail.gmail.com>
From: Wladimir <laanwj@gmail.com>
To: Jack Scott <jack.scott.public@gmail.com>
Content-Type: multipart/alternative; boundary=20cf303f6dce48ebdb04f4888b78
Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Physical key / edge detection software
 and PIN to generate private key
Precedence: list

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On Fri, Mar 14, 2014 at 3:38 AM, Jack Scott <jack.scott.public@gmail.com>wrote:

> A method is proposed to generate a Bitcoin private key by using a physical
> key in conjunction with image recognition software and a PIN.  Use edge
> detection software applied to incoming video feed to convert the shape of a
> physical key into an equation that describes the key.  The hash of the
> key's equation plus a user generated five digit pin can then be used to
> create a Bitcoin private key.
>

Some practical nits:

- Physical keys are vulnerable to photography-based reproduction attacks.
That gets even worse if you use them to identify to a digital system as you
can leave out the tiresome manual reproduction step.

- The output from computer vision algorithms is notoriously noisy. If you
use that as input for hashing a private key, it may become hard/impossible
to reproduce (also, physical objects may deform over time).

Wladimir

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<div dir=3D"ltr"><div class=3D"gmail_extra"><div class=3D"gmail_quote">On F=
ri, Mar 14, 2014 at 3:38 AM, Jack Scott <span dir=3D"ltr">&lt;<a href=3D"ma=
ilto:jack.scott.public@gmail.com" target=3D"_blank">jack.scott.public@gmail=
.com</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><div dir=3D"ltr"><div>A method is proposed t=
o generate a Bitcoin private key by using a physical key in conjunction wit=
h image recognition software and a PIN. =C2=A0Use edge detection software a=
pplied to incoming video feed to convert the shape of a physical key into a=
n equation that describes the key. =C2=A0The hash of the key&#39;s equation=
 plus a user generated five digit pin can then be used to create a Bitcoin =
private key.</div>
</div></blockquote><div><br></div><div>Some practical nits:</div><div><br><=
/div><div>- Physical keys are vulnerable to photography-based reproduction =
attacks. That gets even worse if you use them to identify to a digital syst=
em as you can leave out the tiresome manual reproduction step.</div>
<div><br></div><div>- The output from computer vision algorithms is notorio=
usly noisy. If you use that as input for hashing a private key, it may beco=
me hard/impossible to reproduce (also, physical objects may deform over tim=
e).</div>
<div><br></div><div>Wladimir</div><div><br></div></div></div></div>

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