To: bitcoin-dev@lists.linuxfoundation.org
From: Andreas Schildbach <andreas@schildbach.de>
Date: Thu, 8 Nov 2018 16:28:41 +0100
Message-ID: <ps1kj6$fk5$1@blaine.gmane.org>
References: <CAEPKjgeJX7-LaJNkVk0GKbC5KhOE0aT+otpa-N1EVtwC35m9LQ@mail.gmail.com>
	<prvlaj$8er$1@blaine.gmane.org> <20181108131130.134b2d43@simplexum.com>
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In-Reply-To: <20181108131130.134b2d43@simplexum.com>
Content-Language: en-US
Subject: Re: [bitcoin-dev] BIP Proposal - Address Paste Improvement
Precedence: list

On 08/11/2018 09.11, Dmitry Petukhov via bitcoin-dev wrote:

>> Copying addresses to the clipboard should be discouraged, rather than
>> supported.
> 
> Do you know any reasonably convenient mechanism for end user to
> transfer an address from, say, a web page to the wallet address
> input field ?

- QR code scanning of a Bitcoin URI
- On Android: A "bitcoin:" URI intent or a BIP70 payment message intent
- On desktop OSes there are similar mechanisms to launch Apps from the
browser (e.g. for mailto: links)

> The clipboard is just a low-hanging fruit for malware, anyway. It just
> the most easy point to replace an address. If the computer is
> compromized, malware can edit the web page in the memory of the browser
> process, for example. If it shown as QR code, malware can decode,
> detect that it is an address, and replace the image of QR code.

For editing the clipboard your computer doesn't need to be compromised!
*Any* app can do it, without special permission.

> I think that the only way to protect from this is to add some form of
> authentication for an address - 2fa (transfer checksum via second
> channel), visual fingerprints for addresses, that will are hard to
> detect (and hence, replace) for malware, signing the destination address
> with the key of an address that is already known and checking the
> signature, etc.

For cases where the payee is a well-known entity the BIP70 payment
protocol has authentication via certificates. That doesn't work for the
"the person in front of you is the only trust anchor you have" usecase
though.