From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Mon, 23 Feb 2026 10:51:51 -0800 Received: from mail-oa1-f63.google.com ([209.85.160.63]) by mail.fairlystable.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94.2) (envelope-from ) id 1vub26-0003ch-Dt for bitcoindev@gnusha.org; Mon, 23 Feb 2026 10:51:51 -0800 Received: by mail-oa1-f63.google.com with SMTP id 586e51a60fabf-40f04a08234sf17321933fac.0 for ; Mon, 23 Feb 2026 10:51:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlegroups.com; s=20230601; t=1771872704; x=1772477504; darn=gnusha.org; h=list-unsubscribe:list-subscribe:list-archive:list-help:list-post :list-id:mailing-list:precedence:x-original-sender:mime-version :subject:references:in-reply-to:message-id:to:from:date:sender:from :to:cc:subject:date:message-id:reply-to; bh=gfxREuuPcew0SVIuGbYscO/AxdyEcKMyrrcR0aCdTZo=; b=eNlAnTd1iYRe6H5I9DwPwP9CI0w+5FkPQnUY7zcVe6RYsjnKsoIrVFsD9OUR2niPjd lTcp8cq9pskpBDVtn3ZtW+xnRP94y4cxmOZFcO9eDfGf8QAf33WmiyURdMbL68naLxtH L0ShiWzaIr1FQyQTpeP6msRyBihaAnl7+0+MIuxv3J0MXQ8DpUoGfx1bh0qaE3Oi7yeT hYD99MUwPUQgfl9O0aAOu9HJOi+2RteV3ChmSd+VEQrMICaxHK4XVDzW6WdvToMkGE4R p56/JGLCAM+B9NVagwc1mzzX6rmQfN7lqmxZgnPZXMuh5K/dByr9ylXj/LhEBupQqCap GTvw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1771872704; x=1772477504; darn=gnusha.org; h=list-unsubscribe:list-subscribe:list-archive:list-help:list-post :list-id:mailing-list:precedence:x-original-sender:mime-version :subject:references:in-reply-to:message-id:to:from:date:from:to:cc :subject:date:message-id:reply-to; bh=gfxREuuPcew0SVIuGbYscO/AxdyEcKMyrrcR0aCdTZo=; b=fCa85BiN69efEyPJJrjsdE/MTymFTiJYuR2zh7VCG8A6a0tj4f5mPi8dFKEBuzYwIT cS+zZyAw0NQwsCOCxblukY+UUHn0tO5ZQfDLYD/Sx7nT7pglp+m507rTa+RFEYbuxBwj C2LZb/5wAI+EUxuZsslgIXquCRgK/AgtOKhDGvR9dhp/cwA+iKwyTv2MgUaF0y0h3y8y UZJdb3AkmFPw+KgUvmBPu5lMVNBkVMguYZatP19BRkcDT5x5pXGFU+9KGhnJ81B9DQ+A I4hLpfG2Kx5AwPbEAguZbC3DtxZPoaNAYmen2npWZNWT1sMdxF0y3rI2ab05MaKgFLq1 oKkg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771872704; x=1772477504; h=list-unsubscribe:list-subscribe:list-archive:list-help:list-post :list-id:mailing-list:precedence:x-original-sender:mime-version :subject:references:in-reply-to:message-id:to:from:date:x-beenthere :x-gm-message-state:sender:from:to:cc:subject:date:message-id :reply-to; bh=gfxREuuPcew0SVIuGbYscO/AxdyEcKMyrrcR0aCdTZo=; b=qjdVQnYJCW7c8v3MXf+puM8UfLPzv8tV+eVYOVs5VA0XLgsyb9l4vS2+yTeGRGeXlI /qKuYDkYvQjFmQ8foPvTp2NpGFfvNs71Qn2ci+0PN7LNCE+nNcY5fPfMaMGHKcWTccsG bqclmf82VKMTpD5PulUuWru/mn3bIdmrn3HWp96i8AWux5EGwPSWy63BK3CVJV2ay5SO +P/1cM+2ylBB3nktZyTKO7JsHO2pMBopxHhZioVR51EpCYpq5vi8kV9nRkrrC+fm7wOw rrAaxrrScOMuHsFq9UXCG8tLosj7jpYn83iFGPvHLe9aZy0khRJ1HMn1MJ0uPg3UoHLV XNZQ== Sender: bitcoindev@googlegroups.com X-Forwarded-Encrypted: i=1; AJvYcCXQuataIfSK0avqCqDnz1zsO94DjZM3qPumJp2v6Q0keSkTyffqdgV5kTQRfmRKUhr6etC3jaQRupi3@gnusha.org X-Gm-Message-State: AOJu0YysZOq2ZMGgROVArgb0eE8YNla6VNCYTpDn68TBtsz29qBXJU3v Q8RxHn7iaAdprm6jMAPeaAvbYrn76jZI60qqTer3/Twf1ei/aHxADcKv X-Received: by 2002:a05:6870:70a3:b0:404:33e1:3cc2 with SMTP id 586e51a60fabf-4157ac44158mr4674125fac.13.1771872703903; Mon, 23 Feb 2026 10:51:43 -0800 (PST) X-BeenThere: bitcoindev@googlegroups.com; h="AV1CL+Hmo6N3rPhFBqOEOkG5NRa8ITF5w43u8zSfgcBaImhedQ==" Received: by 2002:a05:6870:b411:b0:3ec:406d:5582 with SMTP id 586e51a60fabf-40eca677fadls7721831fac.2.-pod-prod-04-us; Mon, 23 Feb 2026 10:51:39 -0800 (PST) X-Received: by 2002:a05:6808:3010:b0:460:fce5:2fc2 with SMTP id 5614622812f47-4644638c989mr4643308b6e.44.1771872699688; Mon, 23 Feb 2026 10:51:39 -0800 (PST) Received: by 2002:a05:690c:450f:b0:797:d142:b0fa with SMTP id 00721157ae682-797d142c176ms7b3; Mon, 23 Feb 2026 10:47:09 -0800 (PST) X-Received: by 2002:a05:690c:d95:b0:796:4969:e79f with SMTP id 00721157ae682-79828cf8425mr82762397b3.9.1771872427438; Mon, 23 Feb 2026 10:47:07 -0800 (PST) Date: Mon, 23 Feb 2026 10:47:06 -0800 (PST) From: Isabel Foxen Duke To: Bitcoin Development Mailing List Message-Id: <4b02a925-663f-423f-8905-0fc1b528581fn@googlegroups.com> 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_147806_1328670035.1771872426786" X-Original-Sender: isabel.duke@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_147806_1328670035.1771872426786 Content-Type: multipart/alternative; boundary="----=_Part_147807_1104775907.1771872426786" ------=_Part_147807_1104775907.1771872426786 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable > [1 BTC] can be replaced with something else. For example, if things are= =20 based on the coinbase reward, then these rules can be wired into consensus.= =20 Which means, that if the current block reward is 3.125 BTC plus fees, then= =20 P2PKs can be limited to be X% of the coinbase, and not more than that. I don't mind this idea =E2=80=94 however, I worry it could add complexity f= rom a=20 user experience perspective. 1 BTC might actually make sense and not be so= =20 arbitrary=E2=80=94as it will be an easy number for people to track and unde= rstand=20 what coins they can move or are moving at any given time. Hyper-simplicity= =20 has UX and comms benefits. =20 -Isabel On Tuesday, February 17, 2026 at 9:11:45=E2=80=AFAM UTC-4 Garlo Nicon wrote= : > > My primary complaint is that 1 BTC per block is somewhat arbitrary. > > > Hourglass V2 further restricts the output amount to a maximum of 1=20 > bitcoin per block, or roughly 144 bitcoin per day. This is far less than= =20 > the 450 coins per day introduced by the current block reward subsidy, and= =20 > should effectively mitigate the market impacts of quantum attacks on P2PK= =20 > coins. > > It can be replaced with something else. For example, if things are based= =20 > on the coinbase reward, then these rules can be wired into consensus. Whi= ch=20 > means, that if the current block reward is 3.125 BTC plus fees, then P2PK= s=20 > can be limited to be X% of the coinbase, and not more than that. It would= =20 > still be arbitrary, but it would be more aligned with the explanation fro= m=20 > the BIP, that it is all about how many coins are introduced into=20 > circulation, or assigned to miners. > > Or, if it would be based only on the basic block reward, without fees,=20 > then when all coins will be mined, P2PKs will automatically expire, becau= se=20 > there won't be any amount, which is less than zero satoshis. Because thin= gs=20 > can be based on fees, but then, a large miner with many coins, could game= =20 > the system, and turn some of his own coins into fees, only to unlock more= =20 > P2PK coins. > > pon., 16 lut 2026 o 23:11 Jameson Lopp napisa=C5=82= (a): > >> 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 Group= s=20 >> "Bitcoin Development Mailing List" group. >> To unsubscribe from this group and stop receiving emails from it, send a= n=20 >> email to bitcoindev+...@googlegroups.com. >> > To view this discussion visit=20 >> https://groups.google.com/d/msgid/bitcoindev/CADL_X_eb8byZs3VKORoUzaPoBv= guSbxJ%3DKyKifsQFWFqyqHeRA%40mail.gmail.com=20 >> >> . >> > --=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/= 4b02a925-663f-423f-8905-0fc1b528581fn%40googlegroups.com. ------=_Part_147807_1104775907.1771872426786 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
>=C2=A0 [1 BTC] can be replaced with something else. For example, i= f things are based on the coinbase reward, then these rules can be wired in= to consensus. Which means, that if the current block reward is 3.125 BTC pl= us fees, then P2PKs can be limited to be X% of the coinbase, and not more t= han that.

I don't mind this idea =E2=80=94 however, I worry it c= ould add complexity from a user experience perspective. 1 BTC might actuall= y make sense and not be so arbitrary=E2=80=94as it will be an easy number f= or people to track and understand what coins they can move or are moving at= any given time. Hyper-simplicity has UX and comms benefits.=C2=A0=C2=A0 = =C2=A0 =C2=A0

-Isabel
<= /font>
On Tuesday, February 17, 2026 at 9:11:45=E2=80=AFAM UTC-4 Garlo Nicon wr= ote:
> My primary complaint is that 1 BTC per block is somewhat arbi= trary.

> Hourglass V2 further restricts th= e output amount to a maximum of 1 bitcoin per block, or roughly 144 bitcoin= per day. This is far less than the 450 coins per day introduced by the cur= rent block reward subsidy, and should effectively mitigate the market impac= ts of quantum attacks on P2PK coins.

It can be replaced with somethi= ng else. For example, if things are based on the coinbase reward, then thes= e rules can be wired into consensus. Which means, that if the current block= reward is 3.125 BTC plus fees, then P2PKs can be limited to be X% of the c= oinbase, and not more than that. It would still be arbitrary, but it would = be more aligned with the explanation from the BIP, that it is all about how= many coins are introduced into circulation, or assigned to miners.

= Or, if it would be based only on the basic block reward, without fees, then= when all coins will be mined, P2PKs will automatically expire, because the= re won't be any amount, which is less than zero satoshis. Because thing= s can be based on fees, but then, a large miner with many coins, could game= the system, and turn some of his own coins into fees, only to unlock more = P2PK coins.

pon., 16 lut 2026 o 23:11=C2=A0= Jameson Lopp <jameso...@gmail= .com> napisa=C5=82(a):
Bitcoin is = ultimately a system of rules that are enforced by those who use the system = and hold the keys to spend UTXOs. As such, if a sufficiently large cohort o= f economic power within the system is interested in protecting itself again= st massive liquidation events from malicious actors who arguably are not th= e rightful owners of UTXOs, the incentives are in place for them to do some= thing about it.

I like Hourglass V2 a lot more than V1. = My primary complaint is that 1 BTC per block is somewhat arbitrary. It woul= d be interesting to point to the on-chain statistics of what P2PK UTXO spen= d volume we have seen in recent years.

Additionally, in the context = of my own migration BIP, Hourglass V2 could be complementary to the concept= of offering a ZK quantum safe spending option for folks who fail to migrat= e UTXOs to quantum safe scripts before a set deadline, given that these old= P2PK outputs do not belong to HD wallets and thus the owners would be inca= pable of constructing a ZK proof of HD wallet ownership.

On Fri, Feb 1= 3, 2026 at 5:12=E2=80=AFPM Light <bitco...@lightco.in> wrote:
Bitcoin should not have an in-protocol plunge prote= ction mechanism, and certainly not one that artificially restricts people&#= 39;s ability to spend their coins. I encourage you to withdraw this proposa= l, for the sake of 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 > 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>.

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To view this discussion visit https://groups.google.com/d/msgid/bitcoindev/CADL_= X_eb8byZs3VKORoUzaPoBvguSbxJ%3DKyKifsQFWFqyqHeRA%40mail.gmail.com.

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