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Subject: [bitcoin-dev] Replay attacks make BIP148 and BIP149 untennable
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This is just me putting in my formal objection to BIP148 and BIP149 =
based on my experience with the ETH/ETC hard fork and involvement in =
that drama.
First, it's important to note that ETC/ETH HF is a very different =
situation from BIP148 and all other soft-forks. To those on this mailing =
list, the reasons should be self-evident (one results in two =
incompatible chains, the other doesn't).
However, replay attacks are common to both possibilities (i.e. when =
BIP148 has <51% hash power).
I believe the severity of replay attacks is going unvoiced and is not =
understood within the bitcoin community because of their lack of =
experience with them.
I further believe that replay attacks are the #1 issue with BIP148, =
BIP149, etc., superseding wipeout attacks in severity.
These are not baseless beliefs, they're born out of experience and I =
think anyone will reach the same conclusion upon study.
In a nutshell, replay attacks mean that all talk of there being =
potentially "two coins" as a result of BIP148 is basically nonsense.
Replay attacks effectively eliminate that possibility.
When users go to "sell their legacy coins", they've just sold their 148 =
coins, and vice versa.
Both of the coin-splitting techniques given so far by the proponents =
BIP148 are also untenable:
- Double-spending to self with nLockTime txns is insanely complicated, =
risky, not guaranteed to work, extremely time consuming, and would =
likely result in a massive increase in backlogged transactions and =
increased fees.
- Mixing with 148 coinbase txns destroys fungibility.
Without a coin, there is no real threat from BIP148. Without that =
threat, there is no point to BIP148, and the miners know this.
These and other concerns are outlined and explained in more detail in =
this conversation I had yesterday with John Light:
https://www.youtube.com/watch?v=3D33rL3-p8cPw =
<https://www.youtube.com/watch?v=3D33rL3-p8cPw>
Cheers,
Greg Slepak
--
Please do not email me anything that you are not comfortable also =
sharing with the NSA.
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Content-Transfer-Encoding: quoted-printable
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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dus-ascii"><meta http-equiv=3D"Content-Type" content=3D"text/html=
charset=3Dus-ascii"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D""><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dus-ascii" class=3D""><meta http-equiv=3D"Content-Type" =
content=3D"text/html charset=3Dus-ascii" class=3D""><div =
style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space;" class=3D"">This is just me =
putting in my formal objection to BIP148 and BIP149 based on my =
experience with the ETH/ETC hard fork and involvement in that drama.<div =
class=3D""><br class=3D""></div><div class=3D"">First, it's important to =
note that ETC/ETH HF is a very different situation from BIP148 and all =
other soft-forks. To those on this mailing list, the reasons should be =
self-evident (one results in two incompatible chains, the other =
doesn't).</div><div class=3D""><br class=3D""></div><div =
class=3D"">However, replay attacks are common to both possibilities =
(i.e. when BIP148 has <51% hash power).</div><div class=3D""><br =
class=3D""></div><div class=3D"">I believe the severity of replay =
attacks is going unvoiced and is not understood within the bitcoin =
community because of their lack of experience with them.</div><div =
class=3D""><br class=3D""></div><div class=3D"">I further believe that =
replay attacks are the #1 issue with BIP148, BIP149, etc., superseding =
wipeout attacks in severity.</div><div class=3D""><br =
class=3D""></div><div class=3D"">These are not baseless beliefs, they're =
born out of experience and I think anyone will reach the same conclusion =
upon study.</div><div class=3D""><br class=3D""></div><div class=3D"">In =
a nutshell, replay attacks mean that all talk of there being potentially =
"two coins" as a result of BIP148 is basically nonsense.</div><div =
class=3D""><br class=3D""></div><div class=3D"">Replay attacks =
effectively eliminate that possibility.</div><div class=3D""><br =
class=3D""></div><div class=3D"">When users go to "sell their legacy =
coins", they've just sold their 148 coins, and vice versa.</div><div =
class=3D""><br class=3D""></div><div class=3D"">Both of the =
coin-splitting techniques given so far by the proponents BIP148 are also =
untenable:</div><div class=3D""><br class=3D""></div><div class=3D"">- =
Double-spending to self with nLockTime txns is insanely complicated, =
risky, not guaranteed to work, extremely time consuming, and would =
likely result in a massive increase in backlogged transactions and =
increased fees.</div><div class=3D""><br class=3D""></div><div =
class=3D"">- Mixing with 148 coinbase txns destroys =
fungibility.</div><div class=3D""><br class=3D""></div><div =
class=3D"">Without a coin, there is no real threat from BIP148. Without =
that threat, there is no point to BIP148, and the miners know =
this.</div><div class=3D""><br class=3D""></div><div class=3D"">These =
and other concerns are outlined and explained in more detail in this =
conversation I had yesterday with John Light:</div><div class=3D""><br =
class=3D""></div><div class=3D""><a =
href=3D"https://www.youtube.com/watch?v=3D33rL3-p8cPw" =
class=3D"">https://www.youtube.com/watch?v=3D33rL3-p8cPw</a></div><div =
class=3D""><br class=3D""></div><div class=3D"">Cheers,</div><div =
class=3D"">Greg Slepak</div><div class=3D""><div class=3D"">
<span style=3D"color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
14px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; font-variant-ligatures: normal; =
font-variant-position: normal; font-variant-numeric: normal; =
font-variant-alternates: normal; font-variant-east-asian: normal; =
line-height: normal; orphans: 2; widows: 2;" class=3D""><br =
class=3D"Apple-interchange-newline">--</span><br style=3D"color: rgb(0, =
0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
font-variant-ligatures: normal; font-variant-position: normal; =
font-variant-numeric: normal; font-variant-alternates: normal; =
font-variant-east-asian: normal; line-height: normal; orphans: 2; =
widows: 2;" class=3D""><span style=3D"color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 14px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; =
font-variant-ligatures: normal; font-variant-position: normal; =
font-variant-numeric: normal; font-variant-alternates: normal; =
font-variant-east-asian: normal; line-height: normal; orphans: 2; =
widows: 2;" class=3D"">Please do not email me anything that you are not =
comfortable also sharing</span><span style=3D"color: rgb(0, 0, 0); =
font-family: Helvetica; font-size: 14px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
font-variant-ligatures: normal; font-variant-position: normal; =
font-variant-numeric: normal; font-variant-alternates: normal; =
font-variant-east-asian: normal; line-height: normal; orphans: 2; =
widows: 2;" class=3D""> with the NSA.</span>
</div>
<br class=3D""></div></div></body></html>=
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