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Date: Tue, 15 Jul 2025 02:32:16 +0000
To: Jameson Lopp <jameson.lopp@gmail.com>
From: "'conduition' via Bitcoin Development Mailing List" <bitcoindev@googlegroups.com>
Cc: Bitcoin Development Mailing List <bitcoindev@googlegroups.com>
Subject: Re: [bitcoindev] A Post Quantum Migration Proposal
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Hi Jameson,

I like your proposal, and economically so should anyone who owns Bitcoin. I=
 don't see any solid incentive-based motivation to let QCs "free up" vulner=
able coins, other than maybe as an early-warning indicator. This is impossi=
ble to prove, but I personally believe almost all dormant bitcoins that wou=
ld be locked by phase B are already permanently lost (dead addresses, dead =
owners, etc).

I do think we should delay phase B as long as we can, to give as many peopl=
e time to upgrade as possible. The time horizons should be flexible and all=
ow us to react to changes, in case practical quantum computers take much mo=
re/less time to arrive than we expect today.

Commit/reveal protocols described in other mailing list threads are a tempt=
ing way to rescue some quantum-vulnerable funds, without the complexity of =
zk-STARKs... but these protocols would be difficult to explain to users, an=
d they only work for addresses whose pubkeys haven't been exposed yet. This=
 makes implementation hard. It rules out many existing UTXOs, and all P2TR =
UTXOs too. At this point I don't feel commit/reveal is worth the engineerin=
g effort and research given those limitations. It's reasonable that you lef=
t these out of your proposal.

It's true that phase C would require a hard fork if we first deploy phase B=
, because phase B explicitly closes the door on spending from pre-quantum a=
ddresses. However,=C2=A0I believe zk-STARK proof unlocking could be execute=
d as a soft fork if you combine phases B and C together into a single upgra=
de. This way, there is never a delta in the consensus rules in which EC spe=
nding rules need to be relaxed.=C2=A0


-   Before: allow spending P2PKH if given a valid sig/pubkey.=C2=A0
-   After: allow spending P2PKH if given a valid sig/pubkey AND a valid ZK =
proof of seed-phrase-based key derivation (e.g. BIP39).=C2=A0



With this combined approach, we would never see a period of time in which a=
verage users with mnemonic-seed wallets are locked out of their funds, and =
we need no hard forks at all.


regards,
conduition

On Saturday, July 12th, 2025 at 5:46 PM, Jameson Lopp <jameson.lopp@gmail.c=
om> wrote:

> Building upon my earlier essay against allowing quantum recovery of bitco=
in I wish to formalize a proposal after several months of discussions.
>=20

> This proposal does not delve into the multitude of issues regarding post =
quantum cryptography and trade-offs of different schemes, but rather is mea=
nt to specifically address the issues of incentivizing adoption and migrati=
on of funds after consensus is established that it is prudent to do so.
>=20

> As such, this proposal requires P2QRH as described in BIP-360 or potentia=
l future proposals.
>=20

> Abstract
> --------
>=20

> This proposal follows the implementation of post-quantum (PQ) output type=
 (P2QRH) and introduces a pre-announced sunset of legacy ECDSA/Schnorr sign=
atures. It turns quantum security into a private incentive: fail to upgrade=
 and you will certainly lose access to your funds, creating a certainty whe=
re none previously existed.
>=20

> -   Phase A: Disallows sending of any funds to quantum-vulnerable address=
es, hastening the adoption of P2QRH address types.
>    =20

> -   Phase B: Renders ECDSA/Schnorr spends invalid, preventing all spendin=
g of funds in quantum-vulnerable UTXOs. This is triggered by a well-publici=
zed flag-day roughly five years after activation.
>    =20

> -   Phase C (optional): Pending further research and demand, a separate B=
IP proposing a fork to allow recovery of legacy UTXOs through ZK proof of p=
ossession of BIP-39 seed phrase.
>    =20

>=20

> Motivation
> ----------
>=20

> We seek to secure the value of the UTXO set and minimize incentives for q=
uantum attacks. This proposal is radically different from any in Bitcoin=E2=
=80=99s history just as the threat posed by quantum computing is radically =
different from any other threat in Bitcoin=E2=80=99s history. Never before =
has Bitcoin faced an existential threat to its cryptographic primitives. A =
successful quantum attack on Bitcoin would result in significant economic d=
isruption and damage across the entire ecosystem. Beyond its impact on pric=
e, the ability of miners to provide network security may be significantly i=
mpacted.
>=20

> -   Accelerating quantum progress.
>    =20

>=20

> -   NIST ratified three production-grade PQ signature schemes in 2024; ac=
ademic road-maps now estimate a cryptographically-relevant quantum computer=
 as early as 2027-2030. [McKinsey]
>    =20

>=20

> -   Quantum algorithms are rapidly improving
>    =20

>=20

> -   The safety envelope is shrinking by dramatic increases in algorithms =
even if the pace of hardware improvements is slower. Algorithms are improvi=
ng up to 20X, lowering the theoretical hardware requirements for breaking c=
lassical encryption.
>    =20

>=20

> -   Bitcoin=E2=80=99s exposed public keys.
>    =20

>=20

> -   Roughly 25% of all bitcoin have revealed a public key on-chain; those=
 UTXOs could be stolen with sufficient quantum power.
>    =20

>=20

> -   We may not know the attack is underway.
>    =20

>=20

> -   Quantum attackers could compute the private key for known public keys=
 then transfer all funds weeks or months later, in a covert bleed to not al=
ert chain watchers. Q-Day may be only known much later if the attack withho=
lds broadcasting transactions in order to postpone revealing their capabili=
ties.
>    =20

>=20

> -   Private keys become public.
>    =20

>=20

> -   Assuming that quantum computers are able to maintain their current tr=
ajectories and overcome existing engineering obstacles, there is a near cer=
tain chance that all P2PK (and other outputs with exposed pubkeys) private =
keys will be found and used to steal the funds.
>    =20

>=20

> -   Impossible to know motivations.
>    =20

>=20

> -   Prior to a quantum attack, it is impossible to know the motivations o=
f the attacker. An economically motivated attacker will try to remain undet=
ected for as long as possible, while a malicious attacker will attempt to d=
estroy as much value as possible.
>    =20

>=20

> -   Upgrade inertia.
>    =20

>=20

> -   Coordinating wallets, exchanges, miners and custodians historically t=
akes years.
>    =20

> -   The longer we postpone migration, the harder it becomes to coordinate=
 wallets, exchanges, miners, and custodians. A clear, time-boxed pathway is=
 the only credible defense.
>    =20

> -   Coordinating distributed groups is more prone to delay, even if every=
one has similar motivations. Historically, Bitcoin has been slow to adopt c=
ode changes, often taking multiple years to be approved.
>    =20

>=20

> Benefits at a Glance
> --------------------
>=20

> -   Resilience: Bitcoin protocol remains secure for the foreseeable futur=
e without waiting for a last-minute emergency.
>    =20

> -   Certainty: Bitcoin users and stakeholders gain certainty that a plan =
is both in place and being implemented to effectively deal with the threat =
of quantum theft of bitcoin.
>    =20

> -   Clarity: A single, publicized timeline aligns the entire ecosystem (w=
allets, exchanges, hardware vendors).
>    =20

> -   Supply Discipline: Abandoned keys that never migrate become unspendab=
le, reducing supply, as Satoshi described.
>    =20

>=20

> Specification
> -------------
>=20

> Phase
>=20

> What Happens
>=20

> Who Must Act
>=20

> Time Horizon
>=20

> Phase A - Disallow spends to legacy script types
>=20

> Permitted sends are from legacy scripts to P2QRH scripts
>=20

> Everyone holding or accepting BTC.
>=20

> 3 years after BIP-360 implementation
>=20

> Phase B =E2=80=93 Disallow spends from quantum vulnerable outputs
>=20

> At a preset block-height, nodes reject transactions that rely on ECDSA/Sc=
hnorr keys.
>=20

> Everyone holding or accepting BTC.
>=20

> 2 years after Phase A activation.
>=20

> Phase C =E2=80=93 Re-enable spends from quantum vulnerable outputs via ZK=
 Proof
>=20

> Users with frozen quantum vulnerable funds and a HD wallet seed phrase ca=
n construct a quantum safe ZK proof to recover funds.
>=20

> Users who failed to migrate funds before Phase B.
>=20

> TBD pending research, demand, and consensus.
>=20

>=20

>=20

>=20

>=20

>=20

>=20

>=20

>=20

>=20

>=20

> -------------------------------------------------------------------------=
---------------------------------------------------------------------------=
---------------------------------------------------------------------------=
---------------------------------------------------------------------------=
---------------------------------------------------------------------------=
---------------------------------------------------------------------------=
---------------------------------------------------------------------------=
---------------------------------------------------------------------------=
---------------------------------------------------------------------------=
---------------------------------------------------------------------------=
--------
>=20

> Rationale
> ---------
>=20

> -   Even if Bitcoin is not a primary initial target of a cryptographicall=
y relevant quantum computer, widespread knowledge that such a computer exis=
ts and is capable of breaking Bitcoin=E2=80=99s cryptography will damage fa=
ith in the network .
>    =20

> -   An attack on Bitcoin may not be economically motivated - an attacker =
may be politically or maliciously motivated and may attempt to destroy valu=
e and trust in Bitcoin rather than extract value. There is no way to know i=
n advance how, when, or why an attack may occur. A defensive position must =
be taken well in advance of any attack.
>    =20

> -   Bitcoin=E2=80=99s current signatures (ECDSA/Schnorr) will be a tantal=
izing target: any UTXO that has ever exposed its public key on-chain (rough=
ly 25 % of all bitcoin) could be stolen by a cryptographically relevant qua=
ntum computer.
>    =20

> -   Existing Proposals are Insufficient.
>    =20

>=20

> 1.  Any proposal that allows for the quantum theft of =E2=80=9Clost=E2=80=
=9D bitcoin is creating a redistribution dilemma. There are 3 types of prop=
osals:
>    =20

>=20

> 1.  Allow anyone to steal vulnerable coins, benefitting those who reach q=
uantum capability earliest.
>    =20

> 2.  Allow throttled theft of coins, which leads to RBF battles and ultima=
tely miners subsidizing their revenue from lost coins.
>    =20

> 3.  Allow no one to steal vulnerable coins.
>    =20

>=20

> -   Minimizes attack surface
>    =20

>=20

> 1.  By disallowing new spends to quantum vulnerable script types, we mini=
mize the attack surface with each new UTXO.
>    =20

> 2.  Upgrades to Bitcoin have historically taken many years; this will has=
ten and speed up the adoption of new quantum resistant script types.
>    =20

> 3.  With a clear deadline, industry stakeholders will more readily upgrad=
e existing infrastructure to ensure continuity of services.
>    =20

>=20

> -   Minimizes loss of access to funds
>    =20

>=20

> 1.  If there is sufficient demand and research proves possible, submittin=
g a ZK proof of knowledge of a BIP-39 seed phrase corresponding to a public=
 key hash or script hash would provide a trustless means for legacy outputs=
 to be spent in a quantum resistant manner, even after the sunset.
>    =20

>=20

>=20

>=20

> Stakeholder
>=20

> Incentive to Upgrade
>=20

> Miners
>=20

> =E2=80=A2 Larger size PQ signatures along with incentive for users to mig=
rate will create more demand for block space and thus higher fees collected=
 by miners.
>=20

> =E2=80=A2 Post-Phase B, non-upgraded miners produce invalid blocks.
>=20

> =E2=80=A2 A quantum attack on Bitcoin will significantly devalue both the=
ir hardware and Bitcoin as a whole.
>=20

> Institutional Holders
>=20

> =E2=80=A2 Fiduciary duty: failing to act to prevent a quantum attack on B=
itcoin would violate the fiduciary duty to shareholders.
>=20

> =E2=80=A2 Demonstrating Bitcoin=E2=80=99s ability to effectively mitigate=
 emerging threats will prove Bitcoin to be an investment grade asset.
>=20

> Exchanges & Custodians
>=20

> =E2=80=A2 Concentrated risk: a quantum hack could bankrupt them overnight=
.
>=20

> =E2=80=A2 Early migration is cheap relative to potential losses, potentia=
l lawsuits over improper custody and reputational damage.
>=20

> Everyday Users
>=20

> =E2=80=A2 Self-sovereign peace of mind.
>=20

> =E2=80=A2 Sunset date creates a clear deadline and incentive to improve t=
heir security rather than an open-ended =E2=80=9Csome day=E2=80=9D that inv=
ites procrastination.
>=20

> Attackers
>=20

> =E2=80=A2 Economic incentive diminishes as sunset nears, stolen coins can=
not be spent after Q-day.
>=20

> Key Insight: As mentioned earlier, the proposal turns quantum security in=
to a private incentive to upgrade.
>=20

> This is not an offensive attack, rather, it is defensive: our thesis is t=
hat the Bitcoin ecosystem wishes to defend itself and its interests against=
 those who would prefer to do nothing and allow a malicious actor to destro=
y both value and trust.
>=20

>=20

>=20

> > "Lost coins only make everyone else's coins worth slightly more. Think =
of it as a donation to everyone." - Satoshi Nakamoto
>=20

>=20

>=20

> If true, the corollary is:
>=20

>=20

>=20

> > "Quantum recovered coins only make everyone else's coins worth less. Th=
ink of it as a theft from everyone."
>=20

>=20

>=20

> The timelines that we are proposing are meant to find the best balance be=
tween giving ample ability for account owners to migrate while maintaining =
the integrity of the overall ecosystem to avoid catastrophic attacks.
>=20

>=20

>=20

> Backward Compatibility
> ----------------------
>=20

> As a series of soft forks, older nodes will continue to operate without m=
odification. Non-upgraded nodes, however, will consider all post-quantum wi=
tness programs as anyone-can-spend scripts. They are strongly encouraged to=
 upgrade in order to fully validate the new programs.
>=20

>=20

>=20

> Non-upgraded wallets can receive and send bitcoin from non-upgraded and u=
pgraded wallets until Phase A. After Phase A, they can no longer receive fr=
om any other wallets and can only send to upgraded wallets. After Phase B, =
both senders and receivers will require upgraded wallets. Phase C would lik=
ely require a loosening of consensus rules (a hard fork) to allow vulnerabl=
e funds recovery via ZK proofs.
>=20

> --
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W2O6Al4bdVzx1EkszgN5dhtSUD0GwRgwYcRSWlQzfsvZE0UN5f6HBGXB2zorkGOpdsbDAS_X6xc=
srH6zBIeYbPY8MM_sPfeN9Wblts5Gcog%3D%40proton.me.

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Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div style=3D"font-family: Arial, sans-serif; font-size: 14px;">Hi Jameson,=
</div><div style=3D"font-family: Arial, sans-serif; font-size: 14px;"><br><=
/div><div style=3D"font-family: Arial, sans-serif; font-size: 14px;">I like=
 your proposal, and economically so should anyone who owns Bitcoin. I don't=
 see any solid incentive-based motivation to let QCs "free up" vulnerable c=
oins, other than maybe as an early-warning indicator. This is impossible to=
 prove, but I personally believe almost all dormant bitcoins that would be =
locked by phase B are already permanently lost (dead addresses, dead owners=
, etc).</div><div style=3D"font-family: Arial, sans-serif; font-size: 14px;=
"><br></div><div style=3D"font-family: Arial, sans-serif; font-size: 14px;"=
>I do think we should delay phase B as long as we can, to give as many peop=
le time to upgrade as possible. The time horizons should be flexible and al=
low us to react to changes, in case practical quantum computers take much m=
ore/less time to arrive than we expect today.</div><div style=3D"font-famil=
y: Arial, sans-serif; font-size: 14px;"><br></div><div style=3D"font-family=
: Arial, sans-serif; font-size: 14px;">Commit/reveal protocols described in=
 other mailing list threads are a tempting way to rescue some quantum-vulne=
rable funds, without the complexity of zk-STARKs... but these protocols wou=
ld be difficult to explain to users, and they only work for addresses whose=
 pubkeys haven't been exposed yet. This makes implementation hard. It rules=
 out many existing UTXOs, and all P2TR UTXOs too. At this point I don't fee=
l commit/reveal is worth the engineering effort and research given those li=
mitations. It's reasonable that you left these out of your proposal.</div><=
div style=3D"font-family: Arial, sans-serif; font-size: 14px;"><br></div><d=
iv style=3D"font-family: Arial, sans-serif; font-size: 14px;">It's true tha=
t phase C would require a hard fork if we first deploy phase B, because pha=
se B explicitly closes the door on spending from pre-quantum addresses. How=
ever,&nbsp;<span style=3D"scrollbar-color: rgba(0, 0, 0, 0.35) rgba(0, 0, 0=
, 0);">I believe zk-STARK proof unlocking could be executed as a soft fork =
if you combine phases B and C together into a single upgrade. This way, the=
re is never a delta in the consensus rules in which EC spending rules need =
to be relaxed.&nbsp;</span></div><div style=3D"font-family: Arial, sans-ser=
if; font-size: 14px;"><span style=3D"scrollbar-color: rgba(0, 0, 0, 0.35) r=
gba(0, 0, 0, 0);"><br></span></div><div style=3D"font-family: Arial, sans-s=
erif; font-size: 14px;"><ul data-editing-info=3D"{&quot;orderedStyleType&qu=
ot;:1,&quot;unorderedStyleType&quot;:2}" style=3D"margin-top: 0px; margin-b=
ottom: 0px;"><li style=3D"list-style-type: &quot;- &quot;;"><span><span sty=
le=3D"scrollbar-color: rgba(0, 0, 0, 0.35) rgba(0, 0, 0, 0);"><b>Before</b>=
: allow spending P2PKH if given a valid sig/pubkey.&nbsp;</span></span></li=
><li style=3D"list-style-type: &quot;- &quot;;"><span><span style=3D"scroll=
bar-color: rgba(0, 0, 0, 0.35) rgba(0, 0, 0, 0);"><b>After</b>: allow spend=
ing P2PKH if given a valid sig/pubkey AND a valid ZK proof of seed-phrase-b=
ased key derivation (e.g. BIP39).&nbsp;</span><br></span></li></ul></div><d=
iv style=3D"font-family: Arial, sans-serif; font-size: 14px;"><span style=
=3D"scrollbar-color: rgba(0, 0, 0, 0.35) rgba(0, 0, 0, 0);"><br></span></di=
v><div style=3D"font-family: Arial, sans-serif; font-size: 14px;"><span sty=
le=3D"scrollbar-color: rgba(0, 0, 0, 0.35) rgba(0, 0, 0, 0);">With this com=
bined approach, we would never see a period of time in which average users =
with mnemonic-seed wallets are locked out of their funds, and we need no ha=
rd forks at all.</span></div><div style=3D"font-family: Arial, sans-serif; =
font-size: 14px;"><span style=3D"scrollbar-color: rgba(0, 0, 0, 0.35) rgba(=
0, 0, 0, 0);"><br></span></div><div style=3D"font-family: Arial, sans-serif=
; font-size: 14px;"><span style=3D"scrollbar-color: rgba(0, 0, 0, 0.35) rgb=
a(0, 0, 0, 0);">regards,</span></div><div style=3D"font-family: Arial, sans=
-serif; font-size: 14px;"><span style=3D"scrollbar-color: rgba(0, 0, 0, 0.3=
5) rgba(0, 0, 0, 0);">conduition</span></div><div style=3D"font-family: Ari=
al, sans-serif; font-size: 14px;"><span style=3D"scrollbar-width:thin;scrol=
lbar-color:rgba(0, 0, 0, 0.35) rgba(0, 0, 0, 0)"></span></div><div class=3D=
"protonmail_quote">
        On Saturday, July 12th, 2025 at 5:46 PM, Jameson Lopp &lt;jameson.l=
opp@gmail.com&gt; wrote:<br>
        <blockquote class=3D"protonmail_quote" type=3D"cite">
            <div dir=3D"ltr"><span id=3D"gmail-docs-internal-guid-5ad3cb7f-=
7fff-eaec-9ee0-841259198a5c"><p dir=3D"ltr" style=3D"line-height:1.44;backg=
round-color:rgb(255,255,255);margin-top:12pt;margin-bottom:0pt;padding:0pt =
0pt 12pt"><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;=
,monospace;color:rgb(34,34,34);background-color:transparent;font-weight:400=
;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:=
baseline;white-space:pre-wrap">Building upon my earlier essay </span><a hre=
f=3D"https://groups.google.com/g/bitcoindev/c/uUK6py0Yjq0/m/6peEaa90AQAJ" s=
tyle=3D"text-decoration:none" target=3D"_blank" rel=3D"noreferrer nofollow =
noopener"><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;=
,monospace;color:rgb(17,85,204);background-color:transparent;font-weight:40=
0;font-style:normal;font-variant:normal;text-decoration:underline;vertical-=
align:baseline;white-space:pre-wrap">against allowing quantum recovery of b=
itcoin</span></a><span style=3D"font-size:11pt;font-family:&quot;Courier Ne=
w&quot;,monospace;color:rgb(34,34,34);background-color:transparent;font-wei=
ght:400;font-style:normal;font-variant:normal;text-decoration:none;vertical=
-align:baseline;white-space:pre-wrap"> I wish to formalize a proposal after=
 several months of discussions.</span></p><p dir=3D"ltr" style=3D"line-heig=
ht:1.44;background-color:rgb(255,255,255);margin-top:0pt;margin-bottom:0pt;=
padding:0pt 0pt 12pt"><span style=3D"font-size:11pt;font-family:&quot;Couri=
er New&quot;,monospace;color:rgb(34,34,34);background-color:transparent;fon=
t-weight:400;font-style:normal;font-variant:normal;text-decoration:none;ver=
tical-align:baseline;white-space:pre-wrap">This proposal does not delve int=
o the multitude of issues regarding post quantum cryptography and trade-off=
s of different schemes, but rather is meant to specifically address the iss=
ues of incentivizing adoption and migration of funds </span><span style=3D"=
font-size:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(34,3=
4,34);background-color:transparent;font-weight:400;font-variant:normal;text=
-decoration:none;vertical-align:baseline;white-space:pre-wrap"><i>after</i>=
</span><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,mo=
nospace;color:rgb(34,34,34);background-color:transparent;font-weight:400;fo=
nt-style:normal;font-variant:normal;text-decoration:none;vertical-align:bas=
eline;white-space:pre-wrap"> consensus is established that it is prudent to=
 do so.</span></p><p dir=3D"ltr" style=3D"line-height:1.44;background-color=
:rgb(255,255,255);margin-top:0pt;margin-bottom:12pt"><span style=3D"font-si=
ze:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);back=
ground-color:transparent;font-weight:400;font-style:normal;font-variant:nor=
mal;text-decoration:none;vertical-align:baseline;white-space:pre-wrap">As s=
uch, this proposal requires P2QRH as described in BIP-360 or potential futu=
re proposals.</span></p><h2 dir=3D"ltr" style=3D"line-height:1.38;margin-to=
p:18pt;margin-bottom:4pt"><span style=3D"font-size:17pt;font-family:&quot;C=
ourier New&quot;,monospace;color:rgb(0,0,0);background-color:transparent;fo=
nt-variant-numeric:normal;font-variant-east-asian:normal;font-variant-alter=
nates:normal;vertical-align:baseline">Abstract</span></h2><p dir=3D"ltr" st=
yle=3D"line-height:1.38;margin-top:12pt;margin-bottom:12pt"><span style=3D"=
font-size:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,=
0);background-color:transparent;font-variant-numeric:normal;font-variant-ea=
st-asian:normal;font-variant-alternates:normal;vertical-align:baseline">Thi=
s proposal follows the implementation of post-quantum (PQ) output type (P2Q=
RH) and introduces a pre-announced sunset of legacy ECDSA/Schnorr signature=
s. It turns quantum security into a </span><span style=3D"font-size:11pt;fo=
nt-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);background-col=
or:transparent;font-style:italic;font-variant-numeric:normal;font-variant-e=
ast-asian:normal;font-variant-alternates:normal;vertical-align:baseline">pr=
ivate incentive</span><span style=3D"font-size:11pt;font-family:&quot;Couri=
er New&quot;,monospace;color:rgb(0,0,0);background-color:transparent;font-v=
ariant-numeric:normal;font-variant-east-asian:normal;font-variant-alternate=
s:normal;vertical-align:baseline">: fail to upgrade and you will certainly =
lose access to your funds, creating a certainty where none previously exist=
ed. </span></p><ul style=3D"margin-top:0px;margin-bottom:0px"><li dir=3D"lt=
r" style=3D"list-style-type: disc; font-size: 11pt; font-family: &quot;Cour=
ier New&quot;, monospace; color: rgb(0, 0, 0); background-color: transparen=
t; font-variant-numeric: normal; font-variant-east-asian: normal; font-vari=
ant-alternates: normal; vertical-align: baseline; white-space: pre-wrap;"><=
p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt" r=
ole=3D"presentation"><span style=3D"font-size:11pt;background-color:transpa=
rent;font-weight:700;font-variant-numeric:normal;font-variant-east-asian:no=
rmal;font-variant-alternates:normal;vertical-align:baseline">Phase A:</span=
><span style=3D"font-size:11pt;background-color:transparent;font-variant-nu=
meric:normal;font-variant-east-asian:normal;font-variant-alternates:normal;=
vertical-align:baseline"> Disallows sending of any funds to quantum-vulnera=
ble addresses, hastening the adoption of P2QRH address types.</span></p></l=
i><li dir=3D"ltr" style=3D"list-style-type: disc; font-size: 11pt; font-fam=
ily: &quot;Courier New&quot;, monospace; color: rgb(0, 0, 0); background-co=
lor: transparent; font-variant-numeric: normal; font-variant-east-asian: no=
rmal; font-variant-alternates: normal; vertical-align: baseline; white-spac=
e: pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margi=
n-bottom:0pt" role=3D"presentation"><span style=3D"font-size:11pt;backgroun=
d-color:transparent;font-weight:700;font-variant-numeric:normal;font-varian=
t-east-asian:normal;font-variant-alternates:normal;vertical-align:baseline"=
>Phase B:</span><span style=3D"font-size:11pt;background-color:transparent;=
font-variant-numeric:normal;font-variant-east-asian:normal;font-variant-alt=
ernates:normal;vertical-align:baseline"> Renders ECDSA/Schnorr spends inval=
id, preventing all spending of funds in quantum-vulnerable UTXOs. This is t=
riggered by a well-publicized flag-day roughly five years after activation.=
</span></p></li><li dir=3D"ltr" style=3D"list-style-type: disc; font-size: =
11pt; font-family: &quot;Courier New&quot;, monospace; color: rgb(0, 0, 0);=
 background-color: transparent; font-variant-numeric: normal; font-variant-=
east-asian: normal; font-variant-alternates: normal; vertical-align: baseli=
ne; white-space: pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;margin=
-top:0pt;margin-bottom:6pt" role=3D"presentation"><span style=3D"font-size:=
11pt;background-color:transparent;font-weight:700;font-variant-numeric:norm=
al;font-variant-east-asian:normal;font-variant-alternates:normal;vertical-a=
lign:baseline">Phase C (optional):</span><span style=3D"font-size:11pt;back=
ground-color:transparent;font-variant-numeric:normal;font-variant-east-asia=
n:normal;font-variant-alternates:normal;vertical-align:baseline"> Pending f=
urther research and demand, a separate BIP proposing a fork to allow recove=
ry of legacy UTXOs through ZK proof of possession of BIP-39 seed phrase.  <=
/span></p></li></ul><h2 dir=3D"ltr" style=3D"line-height:1.38;text-align:ju=
stify;margin-top:14pt;margin-bottom:6pt"><span style=3D"font-size:16pt;font=
-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);background-color=
:transparent;font-variant-numeric:normal;font-variant-east-asian:normal;fon=
t-variant-alternates:normal;vertical-align:baseline">Motivation</span></h2>=
<p dir=3D"ltr" style=3D"line-height:1.38;text-align:justify;margin-top:12pt=
;margin-bottom:12pt"><span style=3D"font-size:11pt;font-family:&quot;Courie=
r New&quot;,monospace;color:rgb(0,0,0);background-color:transparent;font-va=
riant-numeric:normal;font-variant-east-asian:normal;font-variant-alternates=
:normal;vertical-align:baseline">We seek to secure the value of the UTXO se=
t</span><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,m=
onospace;color:rgb(0,0,0);background-color:transparent;font-weight:700;font=
-variant-numeric:normal;font-variant-east-asian:normal;font-variant-alterna=
tes:normal;vertical-align:baseline"> </span><span style=3D"font-size:11pt;f=
ont-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);background-co=
lor:transparent;font-variant-numeric:normal;font-variant-east-asian:normal;=
font-variant-alternates:normal;vertical-align:baseline">and minimize incent=
ives for quantum attacks. This proposal is radically different from any in =
Bitcoin=E2=80=99s history just as the threat posed by quantum computing is =
radically different from any other threat in Bitcoin=E2=80=99s history.  Ne=
ver before has Bitcoin faced an existential threat to its cryptographic pri=
mitives. A successful quantum attack on Bitcoin would result in significant=
 economic disruption and damage across the entire ecosystem. Beyond its imp=
act on price, the ability of miners to provide network security may be sign=
ificantly impacted.  </span></p><ul style=3D"margin-top:0px;margin-bottom:0=
px"><li dir=3D"ltr" style=3D"list-style-type: disc; font-size: 11pt; font-f=
amily: &quot;Courier New&quot;, monospace; color: rgb(0, 0, 0); background-=
color: transparent; font-variant-numeric: normal; font-variant-east-asian: =
normal; font-variant-alternates: normal; vertical-align: baseline; white-sp=
ace: pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:12pt;ma=
rgin-bottom:0pt" role=3D"presentation"><span style=3D"font-size:11pt;backgr=
ound-color:transparent;font-weight:700;font-variant-numeric:normal;font-var=
iant-east-asian:normal;font-variant-alternates:normal;vertical-align:baseli=
ne">Accelerating quantum progress.</span><span style=3D"font-size:11pt;back=
ground-color:transparent;font-variant-numeric:normal;font-variant-east-asia=
n:normal;font-variant-alternates:normal;vertical-align:baseline"> </span></=
p></li><ul style=3D"margin-top:0px;margin-bottom:0px"><li dir=3D"ltr" style=
=3D"list-style-type: circle; font-size: 11pt; font-family: &quot;Courier Ne=
w&quot;, monospace; color: rgb(0, 0, 0); background-color: transparent; fon=
t-variant-numeric: normal; font-variant-east-asian: normal; font-variant-al=
ternates: normal; vertical-align: baseline; white-space: pre-wrap;"><p dir=
=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt" role=
=3D"presentation"><span style=3D"font-size:11pt;background-color:transparen=
t;font-variant-numeric:normal;font-variant-east-asian:normal;font-variant-a=
lternates:normal;vertical-align:baseline">NIST ratified three production-gr=
ade PQ signature schemes in 2024; academic road-maps now estimate a cryptog=
raphically-relevant quantum computer as early as 2027-2030. [</span><a href=
=3D"https://www.mckinsey.com/~/media/mckinsey/business%20functions/mckinsey=
%20digital/our%20insights/the%20year%20of%20quantum%20from%20concept%20to%2=
0reality%20in%202025/quantum-monitor-2025.pdf?shouldIndex=3Dfalse" style=3D=
"text-decoration-line:none" target=3D"_blank" rel=3D"noreferrer nofollow no=
opener"><span style=3D"font-size:11pt;background-color:transparent;font-var=
iant-numeric:normal;font-variant-east-asian:normal;font-variant-alternates:=
normal;text-decoration-line:underline;vertical-align:baseline">McKinsey</sp=
an></a><span style=3D"font-size:11pt;background-color:transparent;font-vari=
ant-numeric:normal;font-variant-east-asian:normal;font-variant-alternates:n=
ormal;vertical-align:baseline">]</span></p></li></ul><li dir=3D"ltr" style=
=3D"list-style-type: disc; font-size: 11pt; font-family: &quot;Courier New&=
quot;, monospace; color: rgb(0, 0, 0); background-color: transparent; font-=
weight: 700; font-variant-numeric: normal; font-variant-east-asian: normal;=
 font-variant-alternates: normal; vertical-align: baseline; white-space: pr=
e-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;text-align:justify;margin=
-top:0pt;margin-bottom:0pt" role=3D"presentation"><span style=3D"font-size:=
11pt;background-color:transparent;font-variant-numeric:normal;font-variant-=
east-asian:normal;font-variant-alternates:normal;vertical-align:baseline">Q=
uantum algorithms are rapidly improving</span></p></li><ul style=3D"margin-=
top:0px;margin-bottom:0px"><li dir=3D"ltr" style=3D"list-style-type: circle=
; font-size: 11pt; font-family: &quot;Courier New&quot;, monospace; color: =
rgb(0, 0, 0); background-color: transparent; font-variant-numeric: normal; =
font-variant-east-asian: normal; font-variant-alternates: normal; vertical-=
align: baseline; white-space: pre-wrap;"><p dir=3D"ltr" style=3D"line-heigh=
t:1.38;text-align:justify;margin-top:0pt;margin-bottom:0pt" role=3D"present=
ation"><span style=3D"font-size:11pt;background-color:transparent;font-vari=
ant-numeric:normal;font-variant-east-asian:normal;font-variant-alternates:n=
ormal;vertical-align:baseline">The safety envelope is shrinking by dramatic=
 increases in algorithms even if the pace of hardware improvements is slowe=
r. Algorithms are <a href=3D"https://security.googleblog.com/2025/05/tracki=
ng-cost-of-quantum-factori.html" target=3D"_blank" rel=3D"noreferrer nofoll=
ow noopener">improving up to 20X</a>, lowering the theoretical hardware req=
uirements for breaking classical encryption.</span></p></li></ul><li dir=3D=
"ltr" style=3D"list-style-type: disc; font-size: 11pt; font-family: &quot;C=
ourier New&quot;, monospace; color: rgb(0, 0, 0); background-color: transpa=
rent; font-variant-numeric: normal; font-variant-east-asian: normal; font-v=
ariant-alternates: normal; vertical-align: baseline; white-space: pre-wrap;=
"><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt=
" role=3D"presentation"><span style=3D"font-size:11pt;background-color:tran=
sparent;font-weight:700;font-variant-numeric:normal;font-variant-east-asian=
:normal;font-variant-alternates:normal;vertical-align:baseline">Bitcoin=E2=
=80=99s exposed public keys.</span><span style=3D"font-size:11pt;background=
-color:transparent;font-variant-numeric:normal;font-variant-east-asian:norm=
al;font-variant-alternates:normal;vertical-align:baseline"> </span></p></li=
><ul style=3D"margin-top:0px;margin-bottom:0px"><li dir=3D"ltr" style=3D"li=
st-style-type: circle; font-size: 11pt; font-family: &quot;Courier New&quot=
;, monospace; color: rgb(0, 0, 0); background-color: transparent; font-vari=
ant-numeric: normal; font-variant-east-asian: normal; font-variant-alternat=
es: normal; vertical-align: baseline; white-space: pre-wrap;"><p dir=3D"ltr=
" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt" role=3D"prese=
ntation"><span style=3D"font-size:11pt;background-color:transparent;font-va=
riant-numeric:normal;font-variant-east-asian:normal;font-variant-alternates=
:normal;vertical-align:baseline">Roughly 25% of all bitcoin have revealed a=
 public key on-chain; those UTXOs could be stolen with sufficient quantum p=
ower.  </span></p></li></ul><li dir=3D"ltr" style=3D"list-style-type: disc;=
 font-size: 11pt; font-family: &quot;Courier New&quot;, monospace; color: r=
gb(0, 0, 0); background-color: transparent; font-variant-numeric: normal; f=
ont-variant-east-asian: normal; font-variant-alternates: normal; vertical-a=
lign: baseline; white-space: pre-wrap;"><p dir=3D"ltr" style=3D"line-height=
:1.38;text-align:justify;margin-top:0pt;margin-bottom:0pt" role=3D"presenta=
tion"><span style=3D"font-size:11pt;background-color:transparent;font-weigh=
t:700;font-variant-numeric:normal;font-variant-east-asian:normal;font-varia=
nt-alternates:normal;vertical-align:baseline">We may not know the attack is=
 underway. </span></p></li><ul style=3D"margin-top:0px;margin-bottom:0px"><=
li dir=3D"ltr" style=3D"list-style-type: circle; font-size: 11pt; font-fami=
ly: &quot;Courier New&quot;, monospace; color: rgb(0, 0, 0); background-col=
or: transparent; font-variant-numeric: normal; font-variant-east-asian: nor=
mal; font-variant-alternates: normal; vertical-align: baseline; white-space=
: pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;text-align:justify;ma=
rgin-top:0pt;margin-bottom:0pt" role=3D"presentation"><span style=3D"font-s=
ize:11pt;background-color:transparent;font-variant-numeric:normal;font-vari=
ant-east-asian:normal;font-variant-alternates:normal;vertical-align:baselin=
e">Quantum attackers could compute the private key for known public keys th=
en transfer all funds weeks or months later, in a covert bleed to not alert=
 chain watchers. Q-Day may be only known much later if the attack withholds=
 broadcasting transactions in order to postpone revealing their capabilitie=
s.</span></p></li></ul><li dir=3D"ltr" style=3D"list-style-type: disc; font=
-size: 11pt; font-family: &quot;Courier New&quot;, monospace; color: rgb(0,=
 0, 0); background-color: transparent; font-weight: 700; font-variant-numer=
ic: normal; font-variant-east-asian: normal; font-variant-alternates: norma=
l; vertical-align: baseline; white-space: pre-wrap;"><p dir=3D"ltr" style=
=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt" role=3D"presentation=
"><span style=3D"font-size:11pt;background-color:transparent;font-variant-n=
umeric:normal;font-variant-east-asian:normal;font-variant-alternates:normal=
;vertical-align:baseline">Private keys become public. </span></p></li><ul s=
tyle=3D"margin-top:0px;margin-bottom:0px"><li dir=3D"ltr" style=3D"list-sty=
le-type: circle; font-size: 11pt; font-family: &quot;Courier New&quot;, mon=
ospace; color: rgb(0, 0, 0); background-color: transparent; font-weight: 70=
0; font-variant-numeric: normal; font-variant-east-asian: normal; font-vari=
ant-alternates: normal; vertical-align: baseline; white-space: pre-wrap;"><=
p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt" r=
ole=3D"presentation"><span style=3D"font-size:11pt;background-color:transpa=
rent;font-weight:400;font-variant-numeric:normal;font-variant-east-asian:no=
rmal;font-variant-alternates:normal;vertical-align:baseline">Assuming that =
quantum computers are able to maintain their current trajectories and overc=
ome existing engineering obstacles, there is a near certain chance that all=
 P2PK (and other outputs with exposed pubkeys) private keys will be found a=
nd used to steal the funds.</span></p></li></ul><li dir=3D"ltr" style=3D"li=
st-style-type: disc; font-size: 11pt; font-family: &quot;Courier New&quot;,=
 monospace; color: rgb(0, 0, 0); background-color: transparent; font-weight=
: 700; font-variant-numeric: normal; font-variant-east-asian: normal; font-=
variant-alternates: normal; vertical-align: baseline; white-space: pre-wrap=
;"><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0p=
t" role=3D"presentation"><span style=3D"font-size:11pt;background-color:tra=
nsparent;font-variant-numeric:normal;font-variant-east-asian:normal;font-va=
riant-alternates:normal;vertical-align:baseline">Impossible to know motivat=
ions. </span></p></li><ul style=3D"margin-top:0px;margin-bottom:0px"><li di=
r=3D"ltr" style=3D"list-style-type: circle; font-size: 11pt; font-family: &=
quot;Courier New&quot;, monospace; color: rgb(0, 0, 0); background-color: t=
ransparent; font-weight: 700; font-variant-numeric: normal; font-variant-ea=
st-asian: normal; font-variant-alternates: normal; vertical-align: baseline=
; white-space: pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;margin-t=
op:0pt;margin-bottom:0pt" role=3D"presentation"><span style=3D"font-size:11=
pt;background-color:transparent;font-weight:400;font-variant-numeric:normal=
;font-variant-east-asian:normal;font-variant-alternates:normal;vertical-ali=
gn:baseline">Prior to a quantum attack, it is impossible to know the motiva=
tions of the attacker.  An economically motivated attacker will try to rema=
in undetected for as long as possible, while a malicious attacker will atte=
mpt to destroy as much value as possible.  </span></p></li></ul><li dir=3D"=
ltr" style=3D"list-style-type: disc; font-size: 11pt; font-family: &quot;Co=
urier New&quot;, monospace; color: rgb(0, 0, 0); background-color: transpar=
ent; font-variant-numeric: normal; font-variant-east-asian: normal; font-va=
riant-alternates: normal; vertical-align: baseline; white-space: pre-wrap;"=
><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"=
 role=3D"presentation"><span style=3D"font-size:11pt;background-color:trans=
parent;font-weight:700;font-variant-numeric:normal;font-variant-east-asian:=
normal;font-variant-alternates:normal;vertical-align:baseline">Upgrade iner=
tia.</span><span style=3D"font-size:11pt;background-color:transparent;font-=
variant-numeric:normal;font-variant-east-asian:normal;font-variant-alternat=
es:normal;vertical-align:baseline"> </span></p></li><ul style=3D"margin-top=
:0px;margin-bottom:0px"><li dir=3D"ltr" style=3D"list-style-type: circle; f=
ont-size: 11pt; font-family: &quot;Courier New&quot;, monospace; color: rgb=
(0, 0, 0); background-color: transparent; font-variant-numeric: normal; fon=
t-variant-east-asian: normal; font-variant-alternates: normal; vertical-ali=
gn: baseline; white-space: pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1=
.38;margin-top:0pt;margin-bottom:0pt" role=3D"presentation"><span style=3D"=
font-size:11pt;background-color:transparent;font-variant-numeric:normal;fon=
t-variant-east-asian:normal;font-variant-alternates:normal;vertical-align:b=
aseline">Coordinating wallets, exchanges, miners and custodians historicall=
y takes years.</span></p></li><li dir=3D"ltr" style=3D"list-style-type: cir=
cle; font-size: 11pt; font-family: &quot;Courier New&quot;, monospace; colo=
r: rgb(0, 0, 0); background-color: transparent; font-variant-numeric: norma=
l; font-variant-east-asian: normal; font-variant-alternates: normal; vertic=
al-align: baseline; white-space: pre-wrap;"><p dir=3D"ltr" style=3D"line-he=
ight:1.38;text-align:justify;margin-top:0pt;margin-bottom:0pt" role=3D"pres=
entation"><span style=3D"font-size:11pt;background-color:transparent;font-v=
ariant-numeric:normal;font-variant-east-asian:normal;font-variant-alternate=
s:normal;vertical-align:baseline">The longer we postpone migration, the har=
der it becomes to coordinate wallets, exchanges, miners, and custodians. A =
clear, time-boxed pathway is the only credible defense.</span></p></li><li =
dir=3D"ltr" style=3D"list-style-type: circle; font-size: 11pt; font-family:=
 &quot;Courier New&quot;, monospace; color: rgb(0, 0, 0); background-color:=
 transparent; font-variant-numeric: normal; font-variant-east-asian: normal=
; font-variant-alternates: normal; vertical-align: baseline; white-space: p=
re-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;text-align:justify;margi=
n-top:0pt;margin-bottom:12pt" role=3D"presentation"><span style=3D"font-siz=
e:11pt;background-color:transparent;font-variant-numeric:normal;font-varian=
t-east-asian:normal;font-variant-alternates:normal;vertical-align:baseline"=
>Coordinating distributed groups is more prone to delay, even if everyone h=
as similar motivations. Historically, Bitcoin has been slow to adopt code c=
hanges, often taking multiple years to be approved.</span></p></li></ul></u=
l><h2 dir=3D"ltr" style=3D"line-height:1.38;text-align:justify;margin-top:1=
4pt;margin-bottom:6pt"><span style=3D"font-size:16pt;font-family:&quot;Cour=
ier New&quot;,monospace;color:rgb(0,0,0);background-color:transparent;font-=
variant-numeric:normal;font-variant-east-asian:normal;font-variant-alternat=
es:normal;vertical-align:baseline">Benefits at a Glance</span></h2><ul styl=
e=3D"margin-top:0px;margin-bottom:0px"><li dir=3D"ltr" style=3D"list-style-=
type: disc; font-size: 11pt; font-family: Arial, sans-serif; color: rgb(0, =
0, 0); background-color: transparent; font-variant-numeric: normal; font-va=
riant-east-asian: normal; font-variant-alternates: normal; vertical-align: =
baseline; white-space: pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;=
text-align:justify;margin-top:12pt;margin-bottom:0pt" role=3D"presentation"=
><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,monospac=
e;background-color:transparent;font-weight:700;font-variant-numeric:normal;=
font-variant-east-asian:normal;font-variant-alternates:normal;vertical-alig=
n:baseline">Resilience:</span><span style=3D"font-size:11pt;font-family:&qu=
ot;Courier New&quot;,monospace;background-color:transparent;font-variant-nu=
meric:normal;font-variant-east-asian:normal;font-variant-alternates:normal;=
vertical-align:baseline"> Bitcoin protocol remains secure for the foreseeab=
le future without waiting for a last-minute emergency.</span></p></li><li d=
ir=3D"ltr" style=3D"list-style-type: disc; font-size: 11pt; font-family: Ar=
ial, sans-serif; color: rgb(0, 0, 0); background-color: transparent; font-v=
ariant-numeric: normal; font-variant-east-asian: normal; font-variant-alter=
nates: normal; vertical-align: baseline; white-space: pre-wrap;"><p dir=3D"=
ltr" style=3D"line-height:1.38;text-align:justify;margin-top:0pt;margin-bot=
tom:0pt" role=3D"presentation"><span style=3D"font-size:11pt;font-family:&q=
uot;Courier New&quot;,monospace;background-color:transparent;font-weight:70=
0;font-variant-numeric:normal;font-variant-east-asian:normal;font-variant-a=
lternates:normal;vertical-align:baseline">Certainty</span><span style=3D"fo=
nt-size:11pt;font-family:&quot;Courier New&quot;,monospace;background-color=
:transparent;font-variant-numeric:normal;font-variant-east-asian:normal;fon=
t-variant-alternates:normal;vertical-align:baseline">: Bitcoin users and st=
akeholders gain certainty that a plan is both in place and being implemente=
d to effectively deal with the threat of quantum theft of bitcoin.  </span>=
</p></li><li dir=3D"ltr" style=3D"list-style-type: disc; font-size: 11pt; f=
ont-family: Arial, sans-serif; color: rgb(0, 0, 0); background-color: trans=
parent; font-variant-numeric: normal; font-variant-east-asian: normal; font=
-variant-alternates: normal; vertical-align: baseline; white-space: pre-wra=
p;"><p dir=3D"ltr" style=3D"line-height:1.38;text-align:justify;margin-top:=
0pt;margin-bottom:0pt" role=3D"presentation"><span style=3D"font-size:11pt;=
font-family:&quot;Courier New&quot;,monospace;background-color:transparent;=
font-weight:700;font-variant-numeric:normal;font-variant-east-asian:normal;=
font-variant-alternates:normal;vertical-align:baseline">Clarity:</span><spa=
n style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,monospace;bac=
kground-color:transparent;font-variant-numeric:normal;font-variant-east-asi=
an:normal;font-variant-alternates:normal;vertical-align:baseline"> A single=
, publicized timeline aligns the entire ecosystem (wallets, exchanges, hard=
ware vendors).</span></p></li><li dir=3D"ltr" style=3D"list-style-type: dis=
c; font-size: 11pt; font-family: Arial, sans-serif; color: rgb(0, 0, 0); ba=
ckground-color: transparent; font-variant-numeric: normal; font-variant-eas=
t-asian: normal; font-variant-alternates: normal; vertical-align: baseline;=
 white-space: pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;text-alig=
n:justify;margin-top:0pt;margin-bottom:12pt" role=3D"presentation"><span st=
yle=3D"font-size:11pt;font-family:&quot;Courier New&quot;,monospace;backgro=
und-color:transparent;font-weight:700;font-variant-numeric:normal;font-vari=
ant-east-asian:normal;font-variant-alternates:normal;vertical-align:baselin=
e">Supply Discipline:</span><span style=3D"font-size:11pt;font-family:&quot=
;Courier New&quot;,monospace;background-color:transparent;font-variant-nume=
ric:normal;font-variant-east-asian:normal;font-variant-alternates:normal;ve=
rtical-align:baseline"> Abandoned keys that never migrate become unspendabl=
e, reducing supply, <a href=3D"https://bitcointalk.org/index.php?topic=3D19=
8.msg1647#msg1647" target=3D"_blank" rel=3D"noreferrer nofollow noopener">a=
s Satoshi described</a></span><span style=3D"font-size:11pt;font-family:&qu=
ot;Courier New&quot;,monospace;background-color:transparent;font-variant-nu=
meric:normal;font-variant-east-asian:normal;font-variant-alternates:normal;=
vertical-align:baseline">.  </span></p></li></ul><h2 dir=3D"ltr" style=3D"l=
ine-height:1.38;text-align:justify;margin-top:12pt;margin-bottom:12pt"><spa=
n style=3D"font-size:16pt;font-family:&quot;Courier New&quot;,monospace;col=
or:rgb(0,0,0);background-color:transparent;font-variant-numeric:normal;font=
-variant-east-asian:normal;font-variant-alternates:normal;vertical-align:ba=
seline">Specification</span></h2><h2 dir=3D"ltr" style=3D"line-height:1.38;=
text-align:justify;margin-top:12pt;margin-bottom:12pt"><span style=3D"font-=
weight:normal" id=3D"gmail-docs-internal-guid-4cbd2b46-7fff-d44c-45ec-e5d20=
a70bc82"><div dir=3D"ltr" style=3D"margin-left:0pt" align=3D"left"><table s=
tyle=3D"border:none;border-collapse:collapse"><colgroup><col width=3D"181">=
<col width=3D"224"><col width=3D"137"><col width=3D"130"></colgroup><tbody>=
<tr style=3D"height:0pt"><td style=3D"border-width:1pt;border-style:solid;b=
order-color:rgb(0,0,0);vertical-align:top;padding:5pt;overflow:hidden"><p d=
ir=3D"ltr" style=3D"line-height:1.38;text-align:center;margin-top:0pt;margi=
n-bottom:0pt"><span style=3D"font-size:11pt;font-family:&quot;Courier New&q=
uot;,monospace;color:rgb(0,0,0);background-color:transparent;font-weight:70=
0;font-variant-numeric:normal;font-variant-east-asian:normal;font-variant-a=
lternates:normal;vertical-align:baseline">Phase</span></p></td><td style=3D=
"border-width:1pt;border-style:solid;border-color:rgb(0,0,0);vertical-align=
:top;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"line-height:1.38;=
text-align:center;margin-top:0pt;margin-bottom:0pt"><span style=3D"font-siz=
e:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);backg=
round-color:transparent;font-weight:700;font-variant-numeric:normal;font-va=
riant-east-asian:normal;font-variant-alternates:normal;vertical-align:basel=
ine">What Happens</span></p></td><td style=3D"border-width:1pt;border-style=
:solid;border-color:rgb(0,0,0);vertical-align:top;padding:5pt;overflow:hidd=
en"><p dir=3D"ltr" style=3D"line-height:1.38;text-align:center;margin-top:0=
pt;margin-bottom:0pt"><span style=3D"font-size:11pt;font-family:&quot;Couri=
er New&quot;,monospace;color:rgb(0,0,0);background-color:transparent;font-w=
eight:700;font-variant-numeric:normal;font-variant-east-asian:normal;font-v=
ariant-alternates:normal;vertical-align:baseline">Who Must Act</span></p></=
td><td style=3D"border-width:1pt;border-style:solid;border-color:rgb(0,0,0)=
;vertical-align:top;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"li=
ne-height:1.38;text-align:center;margin-top:0pt;margin-bottom:0pt"><span st=
yle=3D"font-size:11pt;font-family:&quot;Courier New&quot;,monospace;color:r=
gb(0,0,0);background-color:transparent;font-weight:700;font-variant-numeric=
:normal;font-variant-east-asian:normal;font-variant-alternates:normal;verti=
cal-align:baseline">Time Horizon</span></p></td></tr><tr style=3D"height:0p=
t"><td style=3D"border-width:1pt;border-style:solid;border-color:rgb(0,0,0)=
;vertical-align:top;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"li=
ne-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"font-size:1=
1pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);backgrou=
nd-color:transparent;font-weight:700;font-variant-numeric:normal;font-varia=
nt-east-asian:normal;font-variant-alternates:normal;vertical-align:baseline=
">Phase A - </span><span style=3D"font-size:11pt;font-family:&quot;Courier =
New&quot;,monospace;color:rgb(0,0,0);background-color:transparent;font-vari=
ant-numeric:normal;font-variant-east-asian:normal;font-variant-alternates:n=
ormal;vertical-align:baseline">Disallow spends to legacy script types</span=
></p></td><td style=3D"border-width:1pt;border-style:solid;border-color:rgb=
(0,0,0);vertical-align:middle;padding:5pt;overflow:hidden"><p dir=3D"ltr" s=
tyle=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"f=
ont-size:10pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0=
);background-color:transparent;font-variant-numeric:normal;font-variant-eas=
t-asian:normal;font-variant-alternates:normal;vertical-align:baseline">Perm=
itted sends are from legacy scripts to P2QRH scripts</span></p></td><td sty=
le=3D"border-width:1pt;border-style:solid;border-color:rgb(0,0,0);vertical-=
align:middle;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"line-heig=
ht:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"font-size:10pt;fon=
t-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);background-colo=
r:transparent;font-style:italic;font-variant-numeric:normal;font-variant-ea=
st-asian:normal;font-variant-alternates:normal;vertical-align:baseline">Eve=
ryone</span><span style=3D"font-size:10pt;font-family:&quot;Courier New&quo=
t;,monospace;color:rgb(0,0,0);background-color:transparent;font-variant-num=
eric:normal;font-variant-east-asian:normal;font-variant-alternates:normal;v=
ertical-align:baseline"> holding or accepting BTC.</span></p></td><td style=
=3D"border-width:1pt;border-style:solid;border-color:rgb(0,0,0);vertical-al=
ign:middle;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"line-height=
:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"font-size:10pt;font-=
family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);background-color:=
transparent;font-variant-numeric:normal;font-variant-east-asian:normal;font=
-variant-alternates:normal;vertical-align:baseline">3 years after BIP-360 i=
mplementation</span></p></td></tr><tr style=3D"height:0pt"><td style=3D"bor=
der-width:1pt;border-style:solid;border-color:rgb(0,0,0);vertical-align:top=
;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"line-height:1.38;marg=
in-top:0pt;margin-bottom:0pt"><span style=3D"font-size:11pt;font-family:&qu=
ot;Courier New&quot;,monospace;color:rgb(0,0,0);background-color:transparen=
t;font-weight:700;font-variant-numeric:normal;font-variant-east-asian:norma=
l;font-variant-alternates:normal;vertical-align:baseline">Phase B =E2=80=93=
 </span><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,m=
onospace;color:rgb(0,0,0);background-color:transparent;font-variant-numeric=
:normal;font-variant-east-asian:normal;font-variant-alternates:normal;verti=
cal-align:baseline">Disallow spends from quantum vulnerable outputs</span><=
/p></td><td style=3D"border-width:1pt;border-style:solid;border-color:rgb(0=
,0,0);vertical-align:middle;padding:5pt;overflow:hidden"><p dir=3D"ltr" sty=
le=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"fon=
t-size:10pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);=
background-color:transparent;font-variant-numeric:normal;font-variant-east-=
asian:normal;font-variant-alternates:normal;vertical-align:baseline">At a p=
reset block-height, nodes reject transactions that rely on ECDSA/Schnorr ke=
ys. </span></p></td><td style=3D"border-width:1pt;border-style:solid;border=
-color:rgb(0,0,0);vertical-align:middle;padding:5pt;overflow:hidden"><p dir=
=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span =
style=3D"font-size:10pt;font-family:&quot;Courier New&quot;,monospace;color=
:rgb(0,0,0);background-color:transparent;font-style:italic;font-variant-num=
eric:normal;font-variant-east-asian:normal;font-variant-alternates:normal;v=
ertical-align:baseline">Everyone</span><span style=3D"font-size:10pt;font-f=
amily:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);background-color:t=
ransparent;font-variant-numeric:normal;font-variant-east-asian:normal;font-=
variant-alternates:normal;vertical-align:baseline"> holding or accepting BT=
C.</span></p></td><td style=3D"border-width:1pt;border-style:solid;border-c=
olor:rgb(0,0,0);vertical-align:middle;padding:5pt;overflow:hidden"><p dir=
=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span =
style=3D"font-size:10pt;font-family:&quot;Courier New&quot;,monospace;color=
:rgb(0,0,0);background-color:transparent;font-variant-numeric:normal;font-v=
ariant-east-asian:normal;font-variant-alternates:normal;vertical-align:base=
line">2 years after Phase A activation.</span></p></td></tr><tr style=3D"he=
ight:0pt"><td style=3D"border-width:1pt;border-style:solid;border-color:rgb=
(0,0,0);vertical-align:top;padding:5pt;overflow:hidden"><p dir=3D"ltr" styl=
e=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"font=
-size:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);b=
ackground-color:transparent;font-weight:700;font-variant-numeric:normal;fon=
t-variant-east-asian:normal;font-variant-alternates:normal;vertical-align:b=
aseline">Phase C =E2=80=93 </span><span style=3D"font-size:11pt;font-family=
:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);background-color:transp=
arent;font-variant-numeric:normal;font-variant-east-asian:normal;font-varia=
nt-alternates:normal;vertical-align:baseline">Re-enable spends from quantum=
 vulnerable outputs via ZK Proof</span></p></td><td style=3D"border-width:1=
pt;border-style:solid;border-color:rgb(0,0,0);vertical-align:middle;padding=
:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0=
pt;margin-bottom:0pt"><span style=3D"font-size:10pt;font-family:&quot;Couri=
er New&quot;,monospace;color:rgb(0,0,0);background-color:transparent;font-v=
ariant-numeric:normal;font-variant-east-asian:normal;font-variant-alternate=
s:normal;vertical-align:baseline">Users with frozen quantum vulnerable fund=
s and a HD wallet seed phrase can construct a quantum safe ZK proof to reco=
ver funds.</span></p></td><td style=3D"border-width:1pt;border-style:solid;=
border-color:rgb(0,0,0);vertical-align:middle;padding:5pt;overflow:hidden">=
<p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt">=
<span style=3D"font-size:10pt;font-family:&quot;Courier New&quot;,monospace=
;color:rgb(0,0,0);background-color:transparent;font-variant-numeric:normal;=
font-variant-east-asian:normal;font-variant-alternates:normal;vertical-alig=
n:baseline">Users who failed to migrate funds before Phase B.</span></p></t=
d><td style=3D"border-width:1pt;border-style:solid;border-color:rgb(0,0,0);=
vertical-align:middle;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"=
line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"font-size=
:10pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);backgr=
ound-color:transparent;font-variant-numeric:normal;font-variant-east-asian:=
normal;font-variant-alternates:normal;vertical-align:baseline">TBD pending =
research, demand, and consensus.</span></p></td></tr></tbody></table></div>=
</span></h2><h2 dir=3D"ltr" style=3D"line-height:1.38;margin-top:14pt;margi=
n-bottom:6pt"><span style=3D"font-size:16pt;font-family:&quot;Courier New&q=
uot;,monospace;color:rgb(0,0,0);background-color:transparent;font-weight:70=
0;font-style:normal;font-variant:normal;text-decoration:none;vertical-align=
:baseline;white-space:pre-wrap">Rationale</span></h2><ul style=3D"margin-to=
p:0px;margin-bottom:0px"><li dir=3D"ltr" style=3D"list-style-type: disc; fo=
nt-size: 11pt; font-family: &quot;Courier New&quot;, monospace; color: rgb(=
0, 0, 0); background-color: transparent; font-variant-numeric: normal; font=
-variant-east-asian: normal; font-variant-alternates: normal; vertical-alig=
n: baseline; white-space: pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.=
38;text-align:justify;margin-top:12pt;margin-bottom:0pt" role=3D"presentati=
on"><span style=3D"font-size:11pt;background-color:transparent;font-variant=
-numeric:normal;font-variant-east-asian:normal;font-variant-alternates:norm=
al;vertical-align:baseline">Even if Bitcoin is not a primary initial target=
 of a cryptographically relevant quantum computer, widespread knowledge tha=
t such a computer exists and is capable of breaking Bitcoin=E2=80=99s crypt=
ography will damage faith in the network . </span></p></li><li dir=3D"ltr" =
style=3D"list-style-type: disc; font-size: 11pt; font-family: &quot;Courier=
 New&quot;, monospace; color: rgb(0, 0, 0); background-color: transparent; =
font-variant-numeric: normal; font-variant-east-asian: normal; font-variant=
-alternates: normal; vertical-align: baseline; white-space: pre-wrap;"><p d=
ir=3D"ltr" style=3D"line-height:1.38;text-align:justify;margin-top:0pt;marg=
in-bottom:0pt" role=3D"presentation"><span style=3D"font-size:11pt;backgrou=
nd-color:transparent;font-variant-numeric:normal;font-variant-east-asian:no=
rmal;font-variant-alternates:normal;vertical-align:baseline">An attack on B=
itcoin may not be economically motivated - an attacker may be politically o=
r maliciously motivated and may attempt to destroy value and trust in Bitco=
in rather than extract value.  There is no way to know in advance how, when=
, or why an attack may occur.  A defensive position must be taken well in a=
dvance of any attack.  </span></p></li><li dir=3D"ltr" style=3D"list-style-=
type: disc; font-size: 11pt; font-family: &quot;Courier New&quot;, monospac=
e; color: rgb(0, 0, 0); background-color: transparent; font-variant-numeric=
: normal; font-variant-east-asian: normal; font-variant-alternates: normal;=
 vertical-align: baseline; white-space: pre-wrap;"><p dir=3D"ltr" style=3D"=
line-height:1.38;text-align:justify;margin-top:0pt;margin-bottom:0pt" role=
=3D"presentation"><span style=3D"font-size:11pt;background-color:transparen=
t;font-variant-numeric:normal;font-variant-east-asian:normal;font-variant-a=
lternates:normal;vertical-align:baseline">Bitcoin=E2=80=99s current signatu=
res (ECDSA/Schnorr) will be a tantalizing target: any UTXO that has ever ex=
posed its public key on-chain (roughly 25 % of all bitcoin) could be stolen=
 by a cryptographically relevant quantum computer.</span></p></li><li dir=
=3D"ltr" style=3D"list-style-type: disc; font-size: 11pt; font-family: Aria=
l, sans-serif; color: rgb(0, 0, 0); background-color: transparent; font-var=
iant-numeric: normal; font-variant-east-asian: normal; font-variant-alterna=
tes: normal; vertical-align: baseline; white-space: pre-wrap;"><p dir=3D"lt=
r" style=3D"line-height:1.38;text-align:justify;margin-top:0pt;margin-botto=
m:0pt" role=3D"presentation"><span style=3D"font-size:11pt;font-family:&quo=
t;Courier New&quot;,monospace;background-color:transparent;font-weight:700;=
font-variant-numeric:normal;font-variant-east-asian:normal;font-variant-alt=
ernates:normal;vertical-align:baseline">Existing Proposals are Insufficient=
.</span><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,m=
onospace;background-color:transparent;font-variant-numeric:normal;font-vari=
ant-east-asian:normal;font-variant-alternates:normal;vertical-align:baselin=
e">  </span></p></li><ol style=3D"margin-top:0px;margin-bottom:0px"><li dir=
=3D"ltr" style=3D"list-style-type: lower-alpha; font-size: 11pt; font-famil=
y: &quot;Courier New&quot;, monospace; color: rgb(0, 0, 0); background-colo=
r: transparent; font-variant-numeric: normal; font-variant-east-asian: norm=
al; font-variant-alternates: normal; vertical-align: baseline; white-space:=
 pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;text-align:justify;mar=
gin-top:0pt;margin-bottom:0pt" role=3D"presentation"><span style=3D"font-si=
ze:11pt;background-color:transparent;font-variant-numeric:normal;font-varia=
nt-east-asian:normal;font-variant-alternates:normal;vertical-align:baseline=
">Any proposal that allows for the quantum theft of =E2=80=9Clost=E2=80=9D =
bitcoin is creating a redistribution dilemma. There are 3 types of proposal=
s:</span></p></li><ol style=3D"margin-top:0px;margin-bottom:0px"><li dir=3D=
"ltr" style=3D"list-style-type: lower-roman; font-size: 11pt; font-family: =
&quot;Courier New&quot;, monospace; color: rgb(0, 0, 0); background-color: =
transparent; font-variant-numeric: normal; font-variant-east-asian: normal;=
 font-variant-alternates: normal; vertical-align: baseline; white-space: pr=
e-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;text-align:justify;margin=
-top:0pt;margin-bottom:0pt" role=3D"presentation"><span style=3D"font-size:=
11pt;background-color:transparent;font-variant-numeric:normal;font-variant-=
east-asian:normal;font-variant-alternates:normal;vertical-align:baseline">A=
llow anyone to steal vulnerable coins, benefitting those who reach quantum =
capability earliest.</span></p></li><li dir=3D"ltr" style=3D"list-style-typ=
e: lower-roman; font-size: 11pt; font-family: &quot;Courier New&quot;, mono=
space; color: rgb(0, 0, 0); background-color: transparent; font-variant-num=
eric: normal; font-variant-east-asian: normal; font-variant-alternates: nor=
mal; vertical-align: baseline; white-space: pre-wrap;"><p dir=3D"ltr" style=
=3D"line-height:1.38;text-align:justify;margin-top:0pt;margin-bottom:0pt" r=
ole=3D"presentation"><span style=3D"font-size:11pt;background-color:transpa=
rent;font-variant-numeric:normal;font-variant-east-asian:normal;font-varian=
t-alternates:normal;vertical-align:baseline">Allow throttled theft of coins=
, which leads to RBF battles and ultimately miners subsidizing their revenu=
e from lost coins.</span></p></li><li dir=3D"ltr" style=3D"list-style-type:=
 lower-roman; font-size: 11pt; font-family: &quot;Courier New&quot;, monosp=
ace; color: rgb(0, 0, 0); background-color: transparent; font-variant-numer=
ic: normal; font-variant-east-asian: normal; font-variant-alternates: norma=
l; vertical-align: baseline; white-space: pre-wrap;"><p dir=3D"ltr" style=
=3D"line-height:1.38;text-align:justify;margin-top:0pt;margin-bottom:0pt" r=
ole=3D"presentation"><span style=3D"font-size:11pt;background-color:transpa=
rent;font-variant-numeric:normal;font-variant-east-asian:normal;font-varian=
t-alternates:normal;vertical-align:baseline">Allow no one to steal vulnerab=
le coins.</span></p></li></ol></ol><li dir=3D"ltr" style=3D"list-style-type=
: disc; font-size: 11pt; font-family: &quot;Courier New&quot;, monospace; c=
olor: rgb(0, 0, 0); background-color: transparent; font-weight: 700; font-v=
ariant-numeric: normal; font-variant-east-asian: normal; font-variant-alter=
nates: normal; vertical-align: baseline; white-space: pre-wrap;"><p dir=3D"=
ltr" style=3D"line-height:1.38;text-align:justify;margin-top:0pt;margin-bot=
tom:0pt" role=3D"presentation"><span style=3D"font-size:11pt;background-col=
or:transparent;font-variant-numeric:normal;font-variant-east-asian:normal;f=
ont-variant-alternates:normal;vertical-align:baseline">Minimizes attack sur=
face</span></p></li><ol style=3D"margin-top:0px;margin-bottom:0px"><li dir=
=3D"ltr" style=3D"list-style-type: lower-alpha; font-size: 11pt; font-famil=
y: &quot;Courier New&quot;, monospace; color: rgb(0, 0, 0); background-colo=
r: transparent; font-variant-numeric: normal; font-variant-east-asian: norm=
al; font-variant-alternates: normal; vertical-align: baseline; white-space:=
 pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;text-align:justify;mar=
gin-top:0pt;margin-bottom:0pt" role=3D"presentation"><span style=3D"font-si=
ze:11pt;background-color:transparent;font-variant-numeric:normal;font-varia=
nt-east-asian:normal;font-variant-alternates:normal;vertical-align:baseline=
">By disallowing new spends to quantum vulnerable script types, we minimize=
 the attack surface with each new UTXO.  </span></p></li><li dir=3D"ltr" st=
yle=3D"list-style-type: lower-alpha; font-size: 11pt; font-family: &quot;Co=
urier New&quot;, monospace; color: rgb(0, 0, 0); background-color: transpar=
ent; font-variant-numeric: normal; font-variant-east-asian: normal; font-va=
riant-alternates: normal; vertical-align: baseline; white-space: pre-wrap;"=
><p dir=3D"ltr" style=3D"line-height:1.38;text-align:justify;margin-top:0pt=
;margin-bottom:0pt" role=3D"presentation"><span style=3D"font-size:11pt;bac=
kground-color:transparent;font-variant-numeric:normal;font-variant-east-asi=
an:normal;font-variant-alternates:normal;vertical-align:baseline">Upgrades =
to Bitcoin have historically taken many years; this will hasten and speed u=
p the adoption of new quantum resistant script types. </span></p></li><li d=
ir=3D"ltr" style=3D"list-style-type: lower-alpha; font-size: 11pt; font-fam=
ily: &quot;Courier New&quot;, monospace; color: rgb(0, 0, 0); background-co=
lor: transparent; font-variant-numeric: normal; font-variant-east-asian: no=
rmal; font-variant-alternates: normal; vertical-align: baseline; white-spac=
e: pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38;text-align:justify;m=
argin-top:0pt;margin-bottom:0pt" role=3D"presentation"><span style=3D"font-=
size:11pt;background-color:transparent;font-variant-numeric:normal;font-var=
iant-east-asian:normal;font-variant-alternates:normal;vertical-align:baseli=
ne">With a clear deadline, industry stakeholders will more readily upgrade =
existing infrastructure to ensure continuity of services.  </span></p></li>=
</ol><li dir=3D"ltr" style=3D"list-style-type: disc; font-size: 11pt; font-=
family: &quot;Courier New&quot;, monospace; color: rgb(0, 0, 0); background=
-color: transparent; font-weight: 700; font-variant-numeric: normal; font-v=
ariant-east-asian: normal; font-variant-alternates: normal; vertical-align:=
 baseline; white-space: pre-wrap;"><p dir=3D"ltr" style=3D"line-height:1.38=
;text-align:justify;margin-top:0pt;margin-bottom:0pt" role=3D"presentation"=
><span style=3D"font-size:11pt;background-color:transparent;font-variant-nu=
meric:normal;font-variant-east-asian:normal;font-variant-alternates:normal;=
vertical-align:baseline">Minimizes loss of access to funds </span></p></li>=
<ol style=3D"margin-top:0px;margin-bottom:0px"><li dir=3D"ltr" style=3D"lis=
t-style-type: lower-alpha; font-size: 11pt; font-family: &quot;Courier New&=
quot;, monospace; color: rgb(0, 0, 0); background-color: transparent; font-=
variant-numeric: normal; font-variant-east-asian: normal; font-variant-alte=
rnates: normal; vertical-align: baseline; white-space: pre-wrap;"><p dir=3D=
"ltr" style=3D"line-height:1.38;text-align:justify;margin-top:0pt;margin-bo=
ttom:12pt" role=3D"presentation"><span style=3D"font-size:11pt;background-c=
olor:transparent;font-variant-numeric:normal;font-variant-east-asian:normal=
;font-variant-alternates:normal;vertical-align:baseline">If there is suffic=
ient demand and research proves possible, submitting a ZK proof of knowledg=
e of a BIP-39 seed phrase corresponding to  a public key hash or script has=
h would provide a trustless means for legacy outputs to be spent in a quant=
um resistant manner, even after the sunset.  </span></p></li></ol></ul><br>=
<div dir=3D"ltr" style=3D"margin-left:0pt" align=3D"left"><table style=3D"b=
order:none;border-collapse:collapse"><colgroup><col width=3D"143"><col widt=
h=3D"539"></colgroup><tbody><tr style=3D"height:27.4463pt"><td style=3D"bor=
der-width:1pt;border-style:solid;border-color:rgb(0,0,0);vertical-align:top=
;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"line-height:1.38;marg=
in-top:0pt;margin-bottom:0pt"><span style=3D"font-size:11pt;font-family:&qu=
ot;Courier New&quot;,monospace;color:rgb(0,0,0);background-color:transparen=
t;font-weight:700;font-variant-numeric:normal;font-variant-east-asian:norma=
l;font-variant-alternates:normal;vertical-align:baseline">Stakeholder</span=
></p></td><td style=3D"border-width:1pt;border-style:solid;border-color:rgb=
(0,0,0);vertical-align:top;padding:5pt;overflow:hidden"><p dir=3D"ltr" styl=
e=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"font=
-size:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);b=
ackground-color:transparent;font-weight:700;font-variant-numeric:normal;fon=
t-variant-east-asian:normal;font-variant-alternates:normal;vertical-align:b=
aseline">Incentive to Upgrade</span></p></td></tr><tr style=3D"height:53.53=
88pt"><td style=3D"border-width:1pt;border-style:solid;border-color:rgb(0,0=
,0);vertical-align:middle;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=
=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"font-=
size:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);ba=
ckground-color:transparent;font-weight:700;font-variant-numeric:normal;font=
-variant-east-asian:normal;font-variant-alternates:normal;vertical-align:ba=
seline">Miners</span></p></td><td style=3D"border-width:1pt;border-style:so=
lid;border-color:rgb(0,0,0);vertical-align:top;padding:5pt;overflow:hidden"=
><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"=
><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,monospac=
e;color:rgb(0,0,0);background-color:transparent;font-variant-numeric:normal=
;font-variant-east-asian:normal;font-variant-alternates:normal;vertical-ali=
gn:baseline">=E2=80=A2 Larger size PQ signatures along with incentive for u=
sers to migrate will create more demand for block space and thus higher fee=
s collected by miners.</span></p><p dir=3D"ltr" style=3D"line-height:1.38;m=
argin-top:0pt;margin-bottom:0pt"><span style=3D"font-size:11pt;font-family:=
&quot;Courier New&quot;,monospace;color:rgb(0,0,0);background-color:transpa=
rent;font-variant-numeric:normal;font-variant-east-asian:normal;font-varian=
t-alternates:normal;vertical-align:baseline">=E2=80=A2 Post-Phase B, non-up=
graded miners produce invalid blocks.</span></p><p dir=3D"ltr" style=3D"lin=
e-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"font-size:11=
pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);backgroun=
d-color:transparent;font-variant-numeric:normal;font-variant-east-asian:nor=
mal;font-variant-alternates:normal;vertical-align:baseline">=E2=80=A2 A qua=
ntum attack on Bitcoin will significantly devalue both their hardware and B=
itcoin as a whole. </span></p></td></tr><tr style=3D"height:52pt"><td style=
=3D"border-width:1pt;border-style:solid;border-color:rgb(0,0,0);vertical-al=
ign:middle;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"line-height=
:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"font-size:11pt;font-=
family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);background-color:=
transparent;font-weight:700;font-variant-numeric:normal;font-variant-east-a=
sian:normal;font-variant-alternates:normal;vertical-align:baseline">Institu=
tional Holders</span></p></td><td style=3D"border-width:1pt;border-style:so=
lid;border-color:rgb(0,0,0);vertical-align:top;padding:5pt;overflow:hidden"=
><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"=
><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,monospac=
e;color:rgb(0,0,0);background-color:transparent;font-variant-numeric:normal=
;font-variant-east-asian:normal;font-variant-alternates:normal;vertical-ali=
gn:baseline">=E2=80=A2 Fiduciary duty: failing to act to prevent a quantum =
attack on Bitcoin would violate the fiduciary duty to shareholders.  </span=
></p><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:=
0pt"><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,mono=
space;color:rgb(0,0,0);background-color:transparent;font-variant-numeric:no=
rmal;font-variant-east-asian:normal;font-variant-alternates:normal;vertical=
-align:baseline">=E2=80=A2 Demonstrating Bitcoin=E2=80=99s ability to effec=
tively mitigate emerging threats will prove Bitcoin to be an investment gra=
de asset.</span></p></td></tr><tr style=3D"height:52pt"><td style=3D"border=
-width:1pt;border-style:solid;border-color:rgb(0,0,0);vertical-align:middle=
;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"line-height:1.38;marg=
in-top:0pt;margin-bottom:0pt"><span style=3D"font-size:11pt;font-family:&qu=
ot;Courier New&quot;,monospace;color:rgb(0,0,0);background-color:transparen=
t;font-weight:700;font-variant-numeric:normal;font-variant-east-asian:norma=
l;font-variant-alternates:normal;vertical-align:baseline">Exchanges &amp; C=
ustodians</span></p></td><td style=3D"border-width:1pt;border-style:solid;b=
order-color:rgb(0,0,0);vertical-align:top;padding:5pt;overflow:hidden"><p d=
ir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"><spa=
n style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,monospace;col=
or:rgb(0,0,0);background-color:transparent;font-variant-numeric:normal;font=
-variant-east-asian:normal;font-variant-alternates:normal;vertical-align:ba=
seline">=E2=80=A2 Concentrated risk: a quantum hack could bankrupt them ove=
rnight.</span></p><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;m=
argin-bottom:0pt"><span style=3D"font-size:11pt;font-family:&quot;Courier N=
ew&quot;,monospace;color:rgb(0,0,0);background-color:transparent;font-varia=
nt-numeric:normal;font-variant-east-asian:normal;font-variant-alternates:no=
rmal;vertical-align:baseline">=E2=80=A2 Early migration is cheap relative t=
o potential losses, potential lawsuits over improper custody and reputation=
al damage.</span></p></td></tr><tr style=3D"height:52pt"><td style=3D"borde=
r-width:1pt;border-style:solid;border-color:rgb(0,0,0);vertical-align:middl=
e;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"line-height:1.38;mar=
gin-top:0pt;margin-bottom:0pt"><span style=3D"font-size:11pt;font-family:&q=
uot;Courier New&quot;,monospace;color:rgb(0,0,0);background-color:transpare=
nt;font-weight:700;font-variant-numeric:normal;font-variant-east-asian:norm=
al;font-variant-alternates:normal;vertical-align:baseline">Everyday Users</=
span></p></td><td style=3D"border-width:1pt;border-style:solid;border-color=
:rgb(0,0,0);vertical-align:top;padding:5pt;overflow:hidden"><p dir=3D"ltr" =
style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"=
font-size:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,=
0);background-color:transparent;font-variant-numeric:normal;font-variant-ea=
st-asian:normal;font-variant-alternates:normal;vertical-align:baseline">=E2=
=80=A2 Self-sovereign peace of mind.</span></p><p dir=3D"ltr" style=3D"line=
-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"font-size:11p=
t;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);background=
-color:transparent;font-variant-numeric:normal;font-variant-east-asian:norm=
al;font-variant-alternates:normal;vertical-align:baseline">=E2=80=A2 Sunset=
 date creates a clear deadline and incentive to improve their security rath=
er than an open-ended =E2=80=9Csome day=E2=80=9D that invites procrastinati=
on.</span></p></td></tr><tr style=3D"height:43.7925pt"><td style=3D"border-=
width:1pt;border-style:solid;border-color:rgb(0,0,0);vertical-align:middle;=
padding:5pt;overflow:hidden"><p dir=3D"ltr" style=3D"line-height:1.38;margi=
n-top:0pt;margin-bottom:0pt"><span style=3D"font-size:11pt;font-family:&quo=
t;Courier New&quot;,monospace;color:rgb(0,0,0);background-color:transparent=
;font-weight:700;font-variant-numeric:normal;font-variant-east-asian:normal=
;font-variant-alternates:normal;vertical-align:baseline">Attackers</span></=
p></td><td style=3D"border-width:1pt;border-style:solid;border-color:rgb(0,=
0,0);vertical-align:top;padding:5pt;overflow:hidden"><p dir=3D"ltr" style=
=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"font-=
size:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);ba=
ckground-color:transparent;font-variant-numeric:normal;font-variant-east-as=
ian:normal;font-variant-alternates:normal;vertical-align:baseline">=E2=80=
=A2 Economic incentive diminishes as sunset nears, stolen coins cannot be s=
pent after Q-day.</span></p></td></tr></tbody></table></div><p dir=3D"ltr" =
style=3D"line-height:1.38;text-align:justify;margin-top:12pt;margin-bottom:=
12pt"><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,mon=
ospace;color:rgb(0,0,0);background-color:transparent;font-weight:700;font-v=
ariant-numeric:normal;font-variant-east-asian:normal;font-variant-alternate=
s:normal;vertical-align:baseline">Key Insight:</span><span style=3D"font-si=
ze:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);back=
ground-color:transparent;font-variant-numeric:normal;font-variant-east-asia=
n:normal;font-variant-alternates:normal;vertical-align:baseline"> As mentio=
ned earlier, the proposal turns quantum security into a </span><span style=
=3D"font-size:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(=
0,0,0);background-color:transparent;font-style:italic;font-variant-numeric:=
normal;font-variant-east-asian:normal;font-variant-alternates:normal;vertic=
al-align:baseline">private incentive to upgrade</span><span style=3D"font-s=
ize:11pt;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);bac=
kground-color:transparent;font-variant-numeric:normal;font-variant-east-asi=
an:normal;font-variant-alternates:normal;vertical-align:baseline">.  </span=
></p><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:=
0pt"><span style=3D"font-size:11pt;font-family:&quot;Courier New&quot;,mono=
space;color:rgb(0,0,0);background-color:transparent;font-variant-numeric:no=
rmal;font-variant-east-asian:normal;font-variant-alternates:normal;vertical=
-align:baseline">This is not an offensive attack, rather, it is defensive: =
our thesis is that the Bitcoin ecosystem wishes to defend itself and its in=
terests against those who would prefer to do nothing and allow a malicious =
actor to destroy both value and trust.  </span></p><p dir=3D"ltr" style=3D"=
line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span style=3D"backgroun=
d-color:transparent;color:rgb(0,0,0);font-family:&quot;Courier New&quot;,mo=
nospace;font-size:11pt;text-align:center"><br></span></p><blockquote style=
=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding=
-left:1ex" class=3D"gmail_quote"><span style=3D"background-color:transparen=
t;color:rgb(0,0,0);font-family:&quot;Courier New&quot;,monospace;font-size:=
11pt;text-align:center">"Lost coins only make everyone else's coins worth s=
lightly more. Think of it as a donation to everyone." - Satoshi Nakamoto</s=
pan></blockquote><br><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0p=
t;margin-bottom:0pt"><span style=3D"font-size:11pt;font-family:&quot;Courie=
r New&quot;,monospace;color:rgb(0,0,0);background-color:transparent;font-va=
riant-numeric:normal;font-variant-east-asian:normal;font-variant-alternates=
:normal;vertical-align:baseline">If true, the corollary is:</span></p><p di=
r=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;margin-bottom:0pt"><span=
 style=3D"background-color:transparent;color:rgb(0,0,0);font-family:&quot;C=
ourier New&quot;,monospace;font-size:11pt;text-align:center"><br></span></p=
><blockquote style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(20=
4,204,204);padding-left:1ex" class=3D"gmail_quote"><span style=3D"backgroun=
d-color:transparent;color:rgb(0,0,0);font-family:&quot;Courier New&quot;,mo=
nospace;font-size:11pt;text-align:center">"Quantum recovered coins only mak=
e everyone else's coins worth less. Think of it as a theft from everyone."<=
/span></blockquote><br><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:=
0pt;margin-bottom:0pt"><span style=3D"font-size:11pt;font-family:&quot;Cour=
ier New&quot;,monospace;color:rgb(0,0,0);background-color:transparent;font-=
variant-numeric:normal;font-variant-east-asian:normal;font-variant-alternat=
es:normal;vertical-align:baseline">The timelines that we are proposing are =
meant to find the best balance between giving ample ability for account own=
ers to migrate while maintaining the integrity of the overall ecosystem to =
avoid catastrophic attacks.  </span></p><br><h2 dir=3D"ltr" style=3D"line-h=
eight:1.38;margin-top:18pt;margin-bottom:4pt"><span style=3D"font-size:17pt=
;font-family:&quot;Courier New&quot;,monospace;color:rgb(0,0,0);background-=
color:transparent;font-variant-numeric:normal;font-variant-east-asian:norma=
l;font-variant-alternates:normal;vertical-align:baseline">Backward Compatib=
ility</span></h2><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt;ma=
rgin-bottom:0pt"><span style=3D"font-size:11pt;font-family:&quot;Courier Ne=
w&quot;,monospace;color:rgb(0,0,0);background-color:transparent;font-varian=
t-numeric:normal;font-variant-east-asian:normal;font-variant-alternates:nor=
mal;vertical-align:baseline">As a series of soft forks, older nodes will co=
ntinue to operate without modification. Non-upgraded nodes, however, will c=
onsider all post-quantum witness programs as anyone-can-spend scripts. They=
 are strongly encouraged to upgrade in order to fully validate the new prog=
rams.</span></p><br><p dir=3D"ltr" style=3D"line-height:1.38;margin-top:0pt=
;margin-bottom:0pt"><span style=3D"font-size:11pt;font-family:&quot;Courier=
 New&quot;,monospace;color:rgb(0,0,0);background-color:transparent;font-var=
iant-numeric:normal;font-variant-east-asian:normal;font-variant-alternates:=
normal;vertical-align:baseline">Non-upgraded wallets can receive and send b=
itcoin from non-upgraded and upgraded wallets until Phase A. After Phase A,=
 they can no longer receive from any other wallets and can only send to upg=
raded wallets.  After Phase B, both senders and receivers will require upgr=
aded wallets. Phase C would likely require a loosening of consensus rules (=
a hard fork) to allow vulnerable funds recovery via ZK proofs.</span></p></=
span></div>

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