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Wed, 18 Feb 2026 23:21:20 -0800 (PST) X-Received: by 2002:a05:6808:f8f:b0:45e:a2fd:3adb with SMTP id 5614622812f47-4639ab5f44amr11066596b6e.11.1771485680800; Wed, 18 Feb 2026 23:21:20 -0800 (PST) Received: by 2002:a05:690c:450f:b0:797:d142:b0fa with SMTP id 00721157ae682-797d142c175ms7b3; Wed, 18 Feb 2026 19:26:03 -0800 (PST) X-Received: by 2002:a05:690c:387:b0:796:3f2f:a326 with SMTP id 00721157ae682-7979e80b01cmr167643457b3.28.1771471562316; Wed, 18 Feb 2026 19:26:02 -0800 (PST) Date: Wed, 18 Feb 2026 19:26:01 -0800 (PST) From: Alex To: Bitcoin Development Mailing List Message-Id: In-Reply-To: References: <9336f5a4-5c28-4c1b-af29-a8462b7a9377n@googlegroups.com> <57bd09bc-1c1b-4605-82f9-65b6b61cf8a2@app.fastmail.com> Subject: Re: [bitcoindev] Hourglass V2 Update MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_1308202_1711335153.1771471561881" X-Original-Sender: alexhultman@gmail.com Precedence: list Mailing-list: list bitcoindev@googlegroups.com; contact bitcoindev+owners@googlegroups.com List-ID: X-Google-Group-Id: 786775582512 List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , X-Spam-Score: -0.5 (/) ------=_Part_1308202_1711335153.1771471561881 Content-Type: multipart/alternative; boundary="----=_Part_1308203_49760287.1771471561881" ------=_Part_1308203_49760287.1771471561881 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable > Bitcoin should not have an in-protocol plunge protection mechanism, and= =20 certainly not one that artificially restricts people's ability to spend=20 their coins. I encourage you to withdraw this proposal, for the sake of=20 bitcoin's integrity and utility as a p2p electronic cash system. The (time) limit is only applicable to legacy P2PK addresses. Anyone can=20 move their funds to modern SegWit/Taproot addresses and continue without=20 any such limit. You are free to insist on using legacy P2PK addresses as=20 you wish, freely, but doing so would put a spending (time) limit much like= =20 current banking KYC limits. Again, insisting on keeping your BTC in=20 specifically legacy P2PK addresses would lead to this (time) limit. All=20 other addresses are unaffected. onsdag 18 februari 2026 kl. 16:20:15 UTC+1 skrev Mike Casey: > Admittedly, the actual value is arbitrary, but it's very easy to relay=20 > conceptually which helps communicate the concept and dissuade this=20 > particular branch of quantum FUD. Fundamentally, it's a trade off betwee= n=20 > how quickly the entire set can be liquidated (if keys are cracked in=20 > advance) and how long and individual original keyholder has to wait to be= =20 > able to exercise dominion over their P2PK coins. In addition to memetics= ,=20 > the 1 BTC amount should provide a very lengthy liquidation period assumin= g=20 > most P2PK keys are lost and cannot be moved prior to implementation. > On Monday, February 16, 2026 at 5:11:09=E2=80=AFPM UTC-5 Jameson Lopp wro= te: > >> Bitcoin is ultimately a system of rules that are enforced by those who= =20 >> use the system and hold the keys to spend UTXOs. As such, if a sufficien= tly=20 >> large cohort of economic power within the system is interested in=20 >> protecting itself against massive liquidation events from malicious acto= rs=20 >> who arguably are not the rightful owners of UTXOs, the incentives are in= =20 >> place for them to do something about it. >> >> I like Hourglass V2 a lot more than V1. My primary complaint is that 1= =20 >> BTC per block is somewhat arbitrary. It would be interesting to point to= =20 >> the on-chain statistics of what P2PK UTXO spend volume we have seen in= =20 >> recent years. >> >> Additionally, in the context of my own migration BIP, Hourglass V2 could= =20 >> be complementary to the concept of offering a ZK quantum safe spending= =20 >> option for folks who fail to migrate UTXOs to quantum safe scripts befor= e a=20 >> set deadline, given that these old P2PK outputs do not belong to HD wall= ets=20 >> and thus the owners would be incapable of constructing a ZK proof of HD= =20 >> wallet ownership. >> >> On Fri, Feb 13, 2026 at 5:12=E2=80=AFPM Light wrot= e: >> >>> Bitcoin should not have an in-protocol plunge protection mechanism, and= =20 >>> certainly not one that artificially restricts people's ability to spend= =20 >>> their coins. I encourage you to withdraw this proposal, for the sake of= =20 >>> bitcoin's integrity and utility as a p2p electronic cash system. >>> >>> On Tue, Feb 10, 2026, at 3:47 PM, Mike Casey wrote: >>> > In response to feedback, the Hourglass proposal to mitigate against= =20 >>> > potential mass liquidation of P2PK funds has been enhanced to further= =20 >>> > limit spend amounts from such outputs to only 1 bitcoin per block. >>> >=20 >>> https://github.com/cryptoquick/bips/blob/hourglass-v2/bip-hourglass-v2.= mediawiki >>> > >>> > Prior discussion of the original Hourglass proposal: >>> > https://groups.google.com/g/bitcoindev/c/zmg3U117aNc/m/lDCMs9j7EAAJ >>> > >>> > Thoughts & feedback welcome! >>> > >>> > --=20 >>> > You received this message because you are subscribed to the Google=20 >>> > Groups "Bitcoin Development Mailing List" group. >>> > To unsubscribe from this group and stop receiving emails from it, sen= d=20 >>> > an email to bitcoindev+...@googlegroups.com. >>> > To view this discussion visit=20 >>> >=20 >>> https://groups.google.com/d/msgid/bitcoindev/9336f5a4-5c28-4c1b-af29-a8= 462b7a9377n%40googlegroups.com=20 >>> > < >>> https://groups.google.com/d/msgid/bitcoindev/9336f5a4-5c28-4c1b-af29-a8= 462b7a9377n%40googlegroups.com?utm_medium=3Demail&utm_source=3Dfooter >>> >. >>> >>> --=20 >>> You received this message because you are subscribed to the Google=20 >>> Groups "Bitcoin Development Mailing List" group. >>> To unsubscribe from this group and stop receiving emails from it, send= =20 >>> an email to bitcoindev+...@googlegroups.com. >>> >> To view this discussion visit=20 >>> https://groups.google.com/d/msgid/bitcoindev/57bd09bc-1c1b-4605-82f9-65= b6b61cf8a2%40app.fastmail.com >>> . >>> >> --=20 You received this message because you are subscribed to the Google Groups "= Bitcoin Development Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to bitcoindev+unsubscribe@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/bitcoindev/= e9b8eac7-0f68-49fc-9301-2be2c3a419b0n%40googlegroups.com. ------=_Part_1308203_49760287.1771471561881 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable > Bitcoin should not have an in-protocol plunge protection mechanism, an= d certainly not one that artificially restricts people's ability to spend t= heir coins. I encourage you to withdraw this proposal, for the sake of bitc= oin's integrity and utility as a p2p electronic cash system.

The= (time) limit is only applicable to legacy P2PK addresses. Anyone can move = their funds to modern SegWit/Taproot addresses and continue without any suc= h limit. You are free to insist on using legacy P2PK addresses as you wish,= freely, but doing so would put a spending (time) limit much like current b= anking KYC limits. Again, insisting on keeping your BTC in specifically leg= acy P2PK addresses would lead to this (time) limit. All other addresses are= unaffected.

onsdag 18 februari 2026 kl. 16:20:15 UTC+1 skrev Mike Casey= :
Admittedly,= the actual value is arbitrary, but it's very easy to relay conceptuall= y which helps communicate the concept and dissuade this particular branch o= f quantum FUD.=C2=A0 Fundamentally, it's a trade off between how quickl= y the entire set can be liquidated (if keys are cracked in advance) and how= long and individual original keyholder has to wait to be able to exercise = dominion over their P2PK coins.=C2=A0 In addition to memetics, the 1 BTC am= ount should provide a very lengthy liquidation period assuming most P2PK ke= ys are lost and cannot be moved prior to implementation.
On Monday, February 16, = 2026 at 5:11:09=E2=80=AFPM UTC-5 Jameson Lopp wrote:
Bitcoin is ultimately a sys= tem of rules that are enforced by those who use the system and hold the key= s to spend UTXOs. As such, if a sufficiently large cohort of economic power= within the system is interested in protecting itself against massive liqui= dation events from malicious actors who arguably are not the rightful owner= s of UTXOs, the incentives are in place for them to do something about it.<= div>
I like Hourglass V2 a lot more than V1. My primary compl= aint is that 1 BTC per block is somewhat arbitrary. It would be interesting= to point to the on-chain statistics of what P2PK UTXO spend volume we have= seen in recent years.

Additionally, in the context of my own migrat= ion BIP, Hourglass V2 could be complementary to the concept of offering a Z= K quantum safe spending option for folks who fail to migrate UTXOs to quant= um safe scripts before a set deadline, given that these old P2PK outputs do= not belong to HD wallets and thus the owners would be incapable of constru= cting a ZK proof of HD wallet ownership.

On Fri, Feb 13, 2026 at 5:12=E2=80=AFPM Light <b= itco...@lightco.in> wrote:
Bitcoin should not have = an in-protocol plunge protection mechanism, and certainly not one that arti= ficially restricts people's ability to spend their coins. I encourage y= ou to withdraw this proposal, for the sake of bitcoin's integrity and u= tility as a p2p electronic cash system.

On Tue, Feb 10, 2026, at 3:47 PM, Mike Casey wrote:
> In response to feedback, the Hourglass proposal to mitigate against > potential mass liquidation of P2PK funds has been enhanced to further =
> limit spend amounts from such outputs to only 1 bitcoin per block.
> https://github.com/cryptoquick/bips/blob/hourglass-v2/bip-hourglass-v2.m= ediawiki
>
> Prior discussion of the original Hourglass proposal:
> https://groups.google.c= om/g/bitcoindev/c/zmg3U117aNc/m/lDCMs9j7EAAJ
>
> Thoughts & feedback welcome!
>
> --
> You received this message because you are subscribed to the Google > Groups "Bitcoin Development Mailing List" group.
> To unsubscribe from this group and stop receiving emails from it, send=
> an email to bitcoindev+...@googlegroups.com. > To view this discussion visit
> https://groups.google.com/d/= msgid/bitcoindev/9336f5a4-5c28-4c1b-af29-a8462b7a9377n%40googlegroups.com
> <https://groups.= google.com/d/msgid/bitcoindev/9336f5a4-5c28-4c1b-af29-a8462b7a9377n%40googl= egroups.com?utm_medium=3Demail&utm_source=3Dfooter>.

--
You received this message because you are subscribed to the Google Groups &= quot;Bitcoin Development Mailing List" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to bitcoindev+...@googlegroups.com.
To view this discussion visit https= ://groups.google.com/d/msgid/bitcoindev/57bd09bc-1c1b-4605-82f9-65b6b61cf8a= 2%40app.fastmail.com.

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To unsubscribe from this group and stop receiving emails from it, send an e= mail to bitcoind= ev+unsubscribe@googlegroups.com.
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