<oembed><type>rich</type><version>1.0</version><author_name>npub1xg2m84malu0cfm4444r0kysx4rgk27e75aj6sz6538kw8fcz627qeadsv7</author_name><author_url>https://nostr.ae/npub1xg2m84malu0cfm4444r0kysx4rgk27e75aj6sz6538kw8fcz627qeadsv7</author_url><provider_name>njump</provider_name><provider_url>https://nostr.ae</provider_url><html>📅 Original date posted:2017-09-28&#xA;📝 Original message:This feels redundant to me; the payment protocol already has an&#xA;expiration time.&#xA;&#xA;&#xA;On 09/27/2017 06:06 PM, Peter Todd via bitcoin-dev wrote:&#xA;&gt; Re-use of old addresses is a major problem, not only for privacy, but also&#xA;&gt; operationally: services like exchanges frequently have problems with users&#xA;&gt; sending funds to addresses whose private keys have been lost or stolen; there&#xA;&gt; are multiple examples of exchanges getting hacked, with users continuing to&#xA;&gt; lose funds well after the actual hack has occured due to continuing deposits.&#xA;&gt; This also makes it difficult operationally to rotate private keys. I personally&#xA;&gt; have even lost funds in the past due to people sending me BTC to addresses that&#xA;&gt; I gave them long ago for different reasons, rather than asking me for fresh&#xA;&gt; one.&#xA;&gt; &#xA;&gt; To help combat this problem, I suggest that we add a UI-level expiration time&#xA;&gt; to the new BIP173 address format. Wallets would be expected to consider&#xA;&gt; addresses as invalid as a destination for funds after the expiration time is&#xA;&gt; reached.&#xA;&gt; &#xA;&gt; Unfortunately, this proposal inevitably will raise a lot of UI and terminology&#xA;&gt; questions. Notably, the entire notion of addresses is flawed from a user point&#xA;&gt; of view: their experience with them should be more like &#34;payment codes&#34;, with a&#xA;&gt; code being valid for payment for a short period of time; wallets should not be&#xA;&gt; displaying addresses as actually associated with specific funds. I suspect&#xA;&gt; we&#39;ll see users thinking that an expired address risks the funds themselves;&#xA;&gt; some thought needs to be put into terminology.&#xA;&gt; &#xA;&gt; Being just an expiration time, seconds-level resolution is unnecessary, and&#xA;&gt; may give the wrong impression. I&#39;d suggest either:&#xA;&gt; &#xA;&gt; 1) Hour resolution - 2^24 hours = 1914 years&#xA;&gt; 2) Month resolution - 2^16 months = 5458 years&#xA;&gt; &#xA;&gt; Both options have the advantage of working well at the UI level regardless of&#xA;&gt; timezone: the former is sufficiently short that UI&#39;s can simply display an&#xA;&gt; &#34;exact&#34; time (though note different leap second interpretations), while the&#xA;&gt; latter is long enough that rounding off to the nearest day in the local&#xA;&gt; timezone is fine.&#xA;&gt; &#xA;&gt; Supporting hour-level (or just seconds) precision has the advantage of making&#xA;&gt; it easy for services like exchanges to use addresses with relatively short&#xA;&gt; validity periods, to reduce the risks of losses after a hack. Also, using at&#xA;&gt; least hour-level ensures we don&#39;t have any year 2038 problems.&#xA;&gt; &#xA;&gt; Thoughts?&#xA;&gt; &#xA;&gt; &#xA;&gt; &#xA;&gt; _______________________________________________&#xA;&gt; bitcoin-dev mailing list&#xA;&gt; bitcoin-dev at lists.linuxfoundation.org&#xA;&gt; https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev&#xA;&gt;</html></oembed>