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From: Gregory Maxwell <greg@xiph.org>
To: Alfie John <alfie@alfie.wtf>,
	 Bitcoin Protocol Discussion
	<bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] BIP 151 MITM
Date: Thu, 9 Jun 2016 01:24:09 +0000	[thread overview]
Message-ID: <CAAS2fgTtu8nqwgrO1u8SRuga6ozcYt7NEDR_tv+cuA3uqgtKvA@mail.gmail.com> (raw)
In-Reply-To: <20160608234728.GQ32334@dosf1.alfie.wtf>

On Wed, Jun 8, 2016 at 11:47 PM, Alfie John via bitcoin-dev
<bitcoin-dev@lists.linuxfoundation.org> wrote:
> Hi folks,
>
> Overall I think BIP 151 is a good idea. However unless I'm mistaken, what's to
> prevent someone between peers to suppress the initial 'encinit' message during
> negotiation, causing both to fallback to plaintext?
>
> Peers should negotiate a secure channel from the outset or backout entirely
> with no option of falling back. This can be indicated loudly by the daemon
> listening on an entirely new port.

Reduction to plaintext isn't an interesting attack vector for an
active attacker: they can simply impersonate the remote side.

This is addressed via authentication, where available, which is done
by a separate specification that builds on this one.

Without authentication this only provides protection against passive attackers.


  reply	other threads:[~2016-06-09  1:24 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-08 23:47 [bitcoin-dev] BIP 151 MITM Alfie John
2016-06-09  1:24 ` Gregory Maxwell [this message]
2016-06-09  1:42   ` Alfie John
2016-06-09  6:57     ` Jonas Schnelli
2016-06-09  7:00       ` Alfie John

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