MIME-Version: 1.0
In-Reply-To: <84976adb75bef1dfdb12b98c19811278@national.shitposting.agency>
References: <84976adb75bef1dfdb12b98c19811278@national.shitposting.agency>
From: Matias Alejo Garcia <ematiu@gmail.com>
Date: Fri, 6 Apr 2018 17:51:11 -0300
Message-ID: <CA+vKqYc3X6ZjVNXs0xgsLGekxPCTcLZj7t2vkyBOV_o=2C2qPA@mail.gmail.com>
To: ketamine@national.shitposting.agency, 
	Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Content-Type: multipart/alternative; boundary="94eb2c04c9329420db0569343817"
Subject: Re: [bitcoin-dev] KETAMINE: Multiple vulnerabilities in
 SecureRandom(), numerous cryptocurrency products affected.
Precedence: list

--94eb2c04c9329420db0569343817
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Source?

On Fri, Apr 6, 2018 at 4:53 PM, ketamine--- via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> A significant number of past and current cryptocurrency products
> contain a JavaScript class named SecureRandom(), containing both
> entropy collection and a PRNG. The entropy collection and the RNG
> itself are both deficient to the degree that key material can be
> recovered by a third party with medium complexity. There are a
> substantial number of variations of this SecureRandom() class in
> various pieces of software, some with bugs fixed, some with additional
> bugs added. Products that aren't today vulnerable due to moving to
> other libraries may be using old keys that have been previously
> compromised by usage of SecureRandom().
>
>
> The most common variations of the library attempts to collect entropy
> from window.crypto's CSPRNG, but due to a type error in a comparison
> this function is silently stepped over without failing. Entropy is
> subsequently gathered from math.Random (a 48bit linear congruential
> generator, seeded by the time in some browsers), and a single
> execution of a medium resolution timer. In some known configurations
> this system has substantially less than 48 bits of entropy.
>
> The core of the RNG is an implementation of RC4 ("arcfour random"),
> and the output is often directly used for the creation of private key
> material as well as cryptographic nonces for ECDSA signatures. RC4 is
> publicly known to have biases of several bits, which are likely
> sufficient for a lattice solver to recover a ECDSA private key given a
> number of signatures. One popular Bitcoin web wallet re-initialized
> the RC4 state for every signature which makes the biases bit-aligned,
> but in other cases the Special K would be manifest itself over
> multiple transactions.
>
>
> Necessary action:
>
>   * identify and move all funds stored using SecureRandom()
>
>   * rotate all key material generated by, or has come into contact
>     with any piece of software using SecureRandom()
>
>   * do not write cryptographic tools in non-type safe languages
>
>   * don't take the output of a CSPRNG and pass it through RC4
>
> -
> 3CJ99vSipFi9z11UdbdZWfNKjywJnY8sT8
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>


--=20
Mat=C3=ADas Alejo Garcia
@ematiu
Roads? Where we're going, we don't need roads!

--94eb2c04c9329420db0569343817
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">Source?=C2=A0</div><div class=3D"gmail_extra"><br><div cla=
ss=3D"gmail_quote">On Fri, Apr 6, 2018 at 4:53 PM, ketamine--- via bitcoin-=
dev <span dir=3D"ltr">&lt;<a href=3D"mailto:bitcoin-dev@lists.linuxfoundati=
on.org" target=3D"_blank">bitcoin-dev@lists.linuxfoundation.org</a>&gt;</sp=
an> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;=
border-left:1px #ccc solid;padding-left:1ex">A significant number of past a=
nd current cryptocurrency products<br>
contain a JavaScript class named SecureRandom(), containing both<br>
entropy collection and a PRNG. The entropy collection and the RNG<br>
itself are both deficient to the degree that key material can be<br>
recovered by a third party with medium complexity. There are a<br>
substantial number of variations of this SecureRandom() class in<br>
various pieces of software, some with bugs fixed, some with additional<br>
bugs added. Products that aren&#39;t today vulnerable due to moving to<br>
other libraries may be using old keys that have been previously<br>
compromised by usage of SecureRandom().<br>
<br>
<br>
The most common variations of the library attempts to collect entropy<br>
from window.crypto&#39;s CSPRNG, but due to a type error in a comparison<br=
>
this function is silently stepped over without failing. Entropy is<br>
subsequently gathered from math.Random (a 48bit linear congruential<br>
generator, seeded by the time in some browsers), and a single<br>
execution of a medium resolution timer. In some known configurations<br>
this system has substantially less than 48 bits of entropy.<br>
<br>
The core of the RNG is an implementation of RC4 (&quot;arcfour random&quot;=
),<br>
and the output is often directly used for the creation of private key<br>
material as well as cryptographic nonces for ECDSA signatures. RC4 is<br>
publicly known to have biases of several bits, which are likely<br>
sufficient for a lattice solver to recover a ECDSA private key given a<br>
number of signatures. One popular Bitcoin web wallet re-initialized<br>
the RC4 state for every signature which makes the biases bit-aligned,<br>
but in other cases the Special K would be manifest itself over<br>
multiple transactions.<br>
<br>
<br>
Necessary action:<br>
<br>
=C2=A0 * identify and move all funds stored using SecureRandom()<br>
<br>
=C2=A0 * rotate all key material generated by, or has come into contact<br>
=C2=A0 =C2=A0 with any piece of software using SecureRandom()<br>
<br>
=C2=A0 * do not write cryptographic tools in non-type safe languages<br>
<br>
=C2=A0 * don&#39;t take the output of a CSPRNG and pass it through RC4<br>
<br>
-<br>
3CJ99vSipFi9z11UdbdZWfNKjywJnY<wbr>8sT8<br>
______________________________<wbr>_________________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank">=
bitcoin-dev@lists.linuxfoundat<wbr>ion.org</a><br>
<a href=3D"https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev" =
rel=3D"noreferrer" target=3D"_blank">https://lists.linuxfoundation.<wbr>org=
/mailman/listinfo/bitcoin-d<wbr>ev</a><br>
</blockquote></div><br><br clear=3D"all"><div><br></div>-- <br><div class=
=3D"gmail_signature" data-smartmail=3D"gmail_signature"><div dir=3D"ltr">Ma=
t=C3=ADas Alejo Garcia<br>@ematiu<br>Roads? Where we&#39;re going, we don&#=
39;t need roads!</div></div>
</div>

--94eb2c04c9329420db0569343817--