<oembed><type>rich</type><version>1.0</version><author_name>npub1m230cem2yh3mtdzkg32qhj73uytgkyg5ylxsu083n3tpjnajxx4qqa2np2</author_name><author_url>https://nostr.ae/npub1m230cem2yh3mtdzkg32qhj73uytgkyg5ylxsu083n3tpjnajxx4qqa2np2</author_url><provider_name>njump</provider_name><provider_url>https://nostr.ae</provider_url><html>📅 Original date posted:2017-09-27&#xA;📝 Original message:Re-use of old addresses is a major problem, not only for privacy, but also&#xA;operationally: services like exchanges frequently have problems with users&#xA;sending funds to addresses whose private keys have been lost or stolen; there&#xA;are multiple examples of exchanges getting hacked, with users continuing to&#xA;lose funds well after the actual hack has occured due to continuing deposits.&#xA;This also makes it difficult operationally to rotate private keys. I personally&#xA;have even lost funds in the past due to people sending me BTC to addresses that&#xA;I gave them long ago for different reasons, rather than asking me for fresh&#xA;one.&#xA;&#xA;To help combat this problem, I suggest that we add a UI-level expiration time&#xA;to the new BIP173 address format. Wallets would be expected to consider&#xA;addresses as invalid as a destination for funds after the expiration time is&#xA;reached.&#xA;&#xA;Unfortunately, this proposal inevitably will raise a lot of UI and terminology&#xA;questions. Notably, the entire notion of addresses is flawed from a user point&#xA;of view: their experience with them should be more like &#34;payment codes&#34;, with a&#xA;code being valid for payment for a short period of time; wallets should not be&#xA;displaying addresses as actually associated with specific funds. I suspect&#xA;we&#39;ll see users thinking that an expired address risks the funds themselves;&#xA;some thought needs to be put into terminology.&#xA;&#xA;Being just an expiration time, seconds-level resolution is unnecessary, and&#xA;may give the wrong impression. I&#39;d suggest either:&#xA;&#xA;1) Hour resolution - 2^24 hours = 1914 years&#xA;2) Month resolution - 2^16 months = 5458 years&#xA;&#xA;Both options have the advantage of working well at the UI level regardless of&#xA;timezone: the former is sufficiently short that UI&#39;s can simply display an&#xA;&#34;exact&#34; time (though note different leap second interpretations), while the&#xA;latter is long enough that rounding off to the nearest day in the local&#xA;timezone is fine.&#xA;&#xA;Supporting hour-level (or just seconds) precision has the advantage of making&#xA;it easy for services like exchanges to use addresses with relatively short&#xA;validity periods, to reduce the risks of losses after a hack. Also, using at&#xA;least hour-level ensures we don&#39;t have any year 2038 problems.&#xA;&#xA;Thoughts?&#xA;&#xA;-- &#xA;https://petertodd.org &#39;peter&#39;[:-1]@petertodd.org&#xA;-------------- next part --------------&#xA;A non-text attachment was scrubbed...&#xA;Name: signature.asc&#xA;Type: application/pgp-signature&#xA;Size: 455 bytes&#xA;Desc: Digital signature&#xA;URL: &lt;http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20170927/7f7c4bfb/attachment.sig&gt;</html></oembed>