From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id EEEB5E92 for ; Wed, 7 Aug 2019 21:19:18 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-ot1-f46.google.com (mail-ot1-f46.google.com [209.85.210.46]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 4B8A9823 for ; Wed, 7 Aug 2019 21:19:18 +0000 (UTC) Received: by mail-ot1-f46.google.com with SMTP id r6so110079516oti.3 for ; Wed, 07 Aug 2019 14:19:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=YdG4gF5HBMcLoojALeSy258/fLn5TE49zaVXVY3ADSk=; b=pF/EvnKC3nDWoGwc5+g8ssnIJpg4xL9oowfW8ELOSvZeIdvLI/d5jyjjMI7KYaLfdy 6gF3hjnR5K/thr7a720TXD/DwSaz++VLYXkKx96Q2Bi+TdsfghZmbkT9QJO1JryrODJm /x64vCogfxI9RCvqHn4Hdr/UskCOQNk3mRF21VRHeECit3pS5Iwz3UOx/odipc9D+Wdv ctFq+WglM/wCiQPWg9ZwulsdI0Ex0QW3zlNWYNjnlm21mJMsUp/I0CAwgeAGXkRh168s frZfDnX7KEGMnwOhtU05DoXEL9p4w/E/67vlj1PAXeCyGhc3VvhS/d3oqF+XctDGER+W 5thQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=YdG4gF5HBMcLoojALeSy258/fLn5TE49zaVXVY3ADSk=; b=JO4Zz7+oGp91MNwSnNu9L7hqSu+S+uPwI3DvTzXYG5SF0grUCPIjcJm0gqe4GNLcrp UKbX0Zl+0y8fZWnGTnKRYHIMdtB5YmBYOS4VgT5nH9xUCff90/VM/K4TeXMf33AJFnmy JWkjFtVFJ2GLGRRxUz0JHCveEtCivX4abOMI8SRMMhDijg0HssKRSeYRvkJXXoqLifd6 nHOvDh7C3vLqlKfDWDt8p/nLHVil3giMCakVnSSTNQ4g9zjWpv9W5vqVm65kPDNtEnpg 0zGj15g+flqZ62qYKbjPW9RWlDt15ZK9haAKo4P7I9OQnBe5TO2Zvc2Iih332XXzuawE UnWg== X-Gm-Message-State: APjAAAWVEAGEqN3Tasj5+A3zU0EMDEx7BCKboh4PMxYs1nbJAN+BBpn0 mRLFZ5gS+x5OEPqnuCOTc0z9uldT6jOwix8gtE4HvQ== X-Google-Smtp-Source: APXvYqymVJk4RTzxGK/TCXm2Whn3l+gpgtioOAHPLhKfJuBwObIZxvIUdy032u2KVbC2YSHGJ2h8S9SuQehzJzo27fw= X-Received: by 2002:a6b:4f0d:: with SMTP id d13mr12062898iob.170.1565212757256; Wed, 07 Aug 2019 14:19:17 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Dustin Dettmer Date: Wed, 7 Aug 2019 14:19:05 -0700 Message-ID: To: Bitcoin Protocol Discussion , Bryan Bishop Content-Type: multipart/alternative; boundary="00000000000064efe2058f8d7e2f" X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, HTML_MESSAGE, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Wed, 07 Aug 2019 21:27:37 +0000 Subject: Re: [bitcoin-dev] Bitcoin vaults with anti-theft recovery/clawback mechanisms X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 Aug 2019 21:19:19 -0000 --00000000000064efe2058f8d7e2f Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Does revaulting vault up with the same keys, or new ones? Are they new derivation paths on the same key? Would love some expanded explanation on how you=E2=80=99re proposing this w= ould work. Thanks, Dustin On Wed, Aug 7, 2019 at 1:35 PM Bryan Bishop via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > Hi, > > One of the biggest problems with the vault scheme (besides all of the > setup data that has to be stored for a long time) is an attacker that > silently steals the hot wallet private key and waits for the vault's > owner to make a delayed-spend transaction to initiate a withdrawal > from the vault. If the user was unaware of the theft of the key, then > the attacker could steal the funds after the delay period. > > To mitigate this, it is important to choose a stipend or withdrawal > amount per withdrawal period like x% of the funds. This limits the > total stolen funds to x% because once the funds are stolen the user > would know their hot key is compromised, and the user would know to > instead use one of the other clawback paths during all of the future > withdrawal delay periods instead of letting the delay timeout all the > way to the (stolen) default/hot key. > > The reason why a loss limiter is the way to go is because there's > currently no way (that I am aware of, without an upgrade) to force an > attacker to reveal his key on the blockchain while also forcing the > attacker to use a timelock before the key can spend the coins. I am > curious about what the smallest least invasive soft-fork would be for > enabling this kind of timelock. There are so many covenant proposals > at this point (CHECKSIGFROMSTACK, SECURETHEBAG, CHECKOUTPUTVERIFY, > ....). Or there's crazy things like a fork that enables a transaction > mode where the (timelock...) script of the first output is > automatically prefixed to any of the other scripts on any of the other > outputs when an input tries to spend in the future. A thief could add > his key to a new output on the transaction and try to spend (just like > a user would with a fresh/rotated key), but the OP_CSV would be > automatically added to his script to implement the public observation > delay window. > > Also, there was other previous work that I was only informed about > today after posting my proposal, so I should mention these as related > work: > > https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-February/015= 793.html > > https://blog.oleganza.com/post/163955782228/how-segwit-makes-security-bet= ter > https://www.youtube.com/watch?v=3DdiNxp3ZTquo > https://bitcointalk.org/index.php?topic=3D5111656 > > - Bryan > http://heybryan.org/ > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > --00000000000064efe2058f8d7e2f Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Does revaulting vault up with the same keys, or new = ones?

Are they new= derivation paths on the same key?

Would love some expanded explanation on how you=E2=80=99re propo= sing this would work.

Th= anks,
Dustin

On Wed, Aug 7, 2019 at 1:35 PM Brya= n Bishop via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
Hi,

One of the biggest problems with the vault scheme (besides all of the
setup data that has to be stored for a long time) is an attacker that
silently steals the hot wallet private key and waits for the vault's owner to make a delayed-spend transaction to initiate a withdrawal
from the vault. If the user was unaware of the theft of the key, then
the attacker could steal the funds after the delay period.

To mitigate this, it is important to choose a stipend or withdrawal
amount per withdrawal period like x% of the funds. This limits the
total stolen funds to x% because once the funds are stolen the user
would know their hot key is compromised, and the user would know to
instead use one of the other clawback paths during all of the future
withdrawal delay periods instead of letting the delay timeout all the
way to the (stolen) default/hot key.

The reason why a loss limiter is the way to go is because there's
currently no way (that I am aware of, without an upgrade) to force an
attacker to reveal his key on the blockchain while also forcing the
attacker to use a timelock before the key can spend the coins. I am
curious about what the smallest least invasive soft-fork would be for
enabling this kind of timelock. There are so many covenant proposals
at this point (CHECKSIGFROMSTACK, SECURETHEBAG, CHECKOUTPUTVERIFY,
....). Or there's crazy things like a fork that enables a transaction mode where the (timelock...) script of the first output is
automatically prefixed to any of the other scripts on any of the other
outputs when an input tries to spend in the future. A thief could add
his key to a new output on the transaction and try to spend (just like
a user would with a fresh/rotated key), but the OP_CSV would be
automatically added to his script to implement the public observation
delay window.

Also, there was other previous work that I was only informed about
today after posting my proposal, so I should mention these as related
work:
https://lists.linux= foundation.org/pipermail/bitcoin-dev/2018-February/015793.html
https://blog.oleganza.co= m/post/163955782228/how-segwit-makes-security-better
https://www.youtube.com/watch?v=3DdiNxp3ZTquo
https://bitcointalk.org/index.php?topic=3D5111656

- Bryan
http:= //heybryan.org/
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bitcoin-dev mailing list
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