Subject: Re: [bitcoin-dev] BIP 151

From: Cameron Garnham <[email-masked]>
Date: Wed, 29 Jun 2016 00:40:23 +0300

Unauthenticated link level encryption is wonderful! MITM attacks are overrated; as they require an active attacker.

Stopping passive attacks is the low hanging fruit. This should be taken first.

Automated and secure peer authentication in a mesh network is a huge topic. One of the unsolved problems in computer science.

A simple 'who is that' by asking for the fingerprint of your peers from your other peers is a very simple way to get 'some' authentication.  Semi-trusted index nodes also is a low hanging fruit for authentication.

However, let's first get unauthenticated encryption. Force the attackers to use active attacks. (That are thousands times more costly to couduct).

Sent from my iPhone

> On 29 Jun 2016, at 00:36, Gregory Maxwell via bitcoin-dev <[email-masked]> wrote:
> 
> On Tue, Jun 28, 2016 at 9:22 PM, Eric Voskuil via bitcoin-dev
> <[email-masked]> wrote:
>> An "out of band key check" is not part of BIP151.
> 
> It has a session ID for this purpose.
> 
>> It requires a secure channel and is authentication. So BIP151 doesn't provide the tools to detect an attack, that requires authentication. A general requirement for authentication is the issue I have raised.
> 
> One might wonder how you ever use a Bitcoin address, or even why we
> might guess these emails from "you" aren't actually coming from the
> NSA.
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