From: Sjors Provoost <sjors@sprovoost.nl>
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Date: Thu, 28 Sep 2017 17:41:42 +0300
References: <20170927160654.GA12492@savin.petertodd.org>
	<oqihpf$5gc$1@blaine.gmane.org>
	<B5DE4E92-C5B3-4C01-A148-E3C46C897323@sprovoost.nl>
	<oqj02k$fj9$1@blaine.gmane.org>
To: Andreas Schildbach <andreas@schildbach.de>,
	Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
In-Reply-To: <oqj02k$fj9$1@blaine.gmane.org>
Message-Id: <14496C9C-E291-4415-B07E-859853579D20@sprovoost.nl>
Subject: Re: [bitcoin-dev] Address expiration times should be added to
	BIP-173
Precedence: list


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Op 28 sep. 2017, om 17:13 heeft Andreas Schildbach via bitcoin-dev =
<bitcoin-dev@lists.linuxfoundation.org> het volgende geschreven:
>=20
> On 09/28/2017 02:43 PM, Sjors Provoost via bitcoin-dev wrote:
>=20
>>> This feels redundant to me; the payment protocol already has an
>>> expiration time.
>>=20
>> The BIP-70 payment protocol has significant overhead and most =
importantly requires back and forth. Emailing a bitcoin address or =
printing it on an invoice is much easier, so I would expect people to =
keep doing that.
>=20
> The payment request message is just as one-way as an address is. It is
> already being emailed and printed on an invoice, in fact it often acts
> as the invoice.

True and the more complicated fields, like a digital signature, are =
optional. Are you suggesting BIP-70 payment requests should be rendered =
with bech32? How long would those be if it's just the address and =
expiration date?

>=20
> Even more problematic, if you were to include an expiry date in a
> BIP-173 address and put that into a payment request, wallets wouldn't =
be
> allowed to parse that expiry date from the script without violating =
the
> BIP70 spec.

Do tools that generate BIP-70 payment requests generate addresses =
themselves or are those input manually by a user? In the former case, I =
assume it could avoid setting the optional expiration date?

Is it not allowed to scan the date even if it then sets the expires =
field to the same (redundant) value?

Sjors

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