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Date: Fri, 27 Mar 2015 00:28:42 +0200
From: s7r <s7r@sky-ip.org>
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To: Gregory Maxwell <gmaxwell@gmail.com>, Tom Harding <tomh@thinlink.com>
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Cc: Bitcoin Development <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Address Expiration to Prevent Reuse
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Reply-To: s7r@sky-ip.org

This should not be enforced by default. There are some use cases where
address re-use is justified (a donation address spread on multiple
static pages or even printed on papers/books?). For example, I offer
some services on the internet for free, and I only have a bitcoin
address for donations which is posted everywhere. Obviously this could
possibly harm privacy, but not everyone who uses bitcoin wants to keep
all transactions private. To the contrary, there are accounting cases
when you need to archive all keys, hashes of transactions and
everything (for example when using btc inside a company which is
required by law to keep accounting registries).

I know it's not recommended to use the same pubkey more than once, but
the protocol was not designed this way. Enforcing something as
described in this topic will undermine an user's rights to re-use his
addresses, if a certain situation requires it.

On 3/26/2015 11:44 PM, Gregory Maxwell wrote:
> On Thu, Mar 26, 2015 at 9:26 PM, Tom Harding <tomh@thinlink.com>=20
> wrote:
>> I should have been clearer that the motivation for address=20
>> expiration is to reduce the rate of increase of the massive pile=20
>> of bitcoin addresses out there which have to be monitored
>> forever for future payments.  It could make a significant dent
>> if something like this worked, and were used by default someday.
>=20
> Great, that can be accomplished by simply encoding an expiration=20
> into the address people are using and specifying that clients=20
> enforce it.
>=20
> ----------------------------------------------------------------------
--------
>
>
>=20
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>=20