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From: Jeff Garzik <jgarzik@bitpay.com>
To: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: [Bitcoin-development] Bitcoin address TTL & key expiration?
Date: Tue, 15 Jul 2014 04:00:41 -0400	[thread overview]
Message-ID: <CAJHLa0M7iEUQnJ9M4A3ev3EQqxUVQG85qucRamvMb0n-CztOFA@mail.gmail.com> (raw)

Proxying another's idea, from CoinSummit.

The request:   It would be useful to limit the lifetime of a bitcoin
address.  Intentionally prevent (somehow) bitcoins being sent to a
pubkey/pkh after the key expires.

You could append "don't ["permit"|confirm] after X [time|block]"  to
the address I suppose.  The metadata would not be digitally signed,
but it would be hash-sealed.  As "address" is a client-side notion,
wallet clients would be the ones enforcing such a rule.

Bitcoin protocol of course knows about keys, and key expiration is a
well known and useful concept in public key cryptography.  The best
insertion point in the protocol for key expiration is an open
question, if it's even a good idea at that level at all.  Some flag
"no more TxOuts exactly like this [after X block?]"?

I readily admit I don't have good answers, but it does seem valuable IMO to
* Prevent users from accidentally sending to an "expired" TxOut/pkh.
This happens in the field.
* Discourage address reuse
* Enable sites that generate lots of keys to rotate ancient keys off
their core systems.  (HD wallets mitigate this)

-- 
Jeff Garzik
Bitcoin core developer and open source evangelist
BitPay, Inc.      https://bitpay.com/



             reply	other threads:[~2014-07-15  8:01 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-15  8:00 Jeff Garzik [this message]
2014-07-15  8:19 ` [Bitcoin-development] Bitcoin address TTL & key expiration? Wladimir
2014-07-15  8:23   ` Jeff Garzik
2014-07-15  8:31     ` Jeremy Spilman
2014-07-15  8:48     ` Wladimir
2014-07-15  8:20 ` Peter Todd
2014-07-15 10:25 ` Mike Hearn
2014-07-15 14:02   ` Jeff Garzik
2014-07-15 14:27     ` Mike Hearn
2014-07-15 14:48 ` Luke Dashjr
2014-07-15 15:11   ` Jeff Garzik
2014-07-15 15:18     ` Mike Hearn
2014-07-15 15:35       ` Jeff Garzik
2014-07-15 15:41     ` Luke Dashjr
2014-07-15 15:55       ` Jeff Garzik
2014-07-15 16:26         ` Mike Hearn

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