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BIP85: revert XPRV breaking changes for application 32' #1673

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BIP85: revert XPRV breaking changes for application 32' #1673

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a3ff1ea
rever XPRV breaking changes for application 32'
scgbckbone Oct 4, 2024
32fef25
changelog corrections
scgbckbone Oct 4, 2024
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12 changes: 6 additions & 6 deletions bip-0085.mediawiki
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Original file line number Diff line number Diff line change
Expand Up @@ -239,9 +239,10 @@ OUTPUT
===XPRV===
Application number: 32'

Consistent with BIP32, use the first (leftmost) 32 bytes of the derived entropy as the
private key<ref name="curve-order" />. Prepend an empty byte (<code>0x00</code>)
per BIP32 on master key serialization. Use the last (rightmost) 32 bytes as the chain code.
Taking 64 bytes of the HMAC digest, the first 32 bytes are the chain code,
and second 32 bytes are the private key for BIP32 XPRV value.
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@jonatack jonatack Oct 4, 2024

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In a3ff1ea, is there a reason not to keep the previous footnote at https://github.com/bitcoin/bips/pull/1600/files#diff-eae7a61b6d2a0b6091c1ce04618f216cbb871d987b985ba712de89e04014654cL379?

Suggested change
and second 32 bytes are the private key for BIP32 XPRV value.
and second 32 bytes[1] are the private key for BIP32 XPRV value.


WARNING: This is not consistent with BIP-032
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@jonatack jonatack Oct 4, 2024

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a3ff1ea nit, may as well use the same convention as the rest of this BIP, not a blocker

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WARNING: This is not consistent with BIP-032
WARNING: This is not consistent with BIP32


Child number, depth, and parent fingerprint are forced to zero, as with any root
private key.
Expand All @@ -258,7 +259,7 @@ INPUT:

OUTPUT
* DERIVED ENTROPY=ead0b33988a616cf6a497f1c169d9e92562604e38305ccd3fc96f2252c177682
* DERIVED XPRV=xprv9s21ZrQH143K4Px85utdpu6DFvY2NpHkJajPoupAznfiacH2MC9LasyW4uvqKXNxLWcjqGTbHKAhoZoMAbmRe5g9tAPA7cUUX4UVA1vFKFm
* DERIVED XPRV=xprv9s21ZrQH143K2srSbCSg4m4kLvPMzcWydgmKEnMmoZUurYuBuYG46c6P71UGXMzmriLzCCBvKQWBUv3vPB3m1SATMhp3uEjXHJ42jFg7myX
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@jonatack jonatack Oct 4, 2024

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Verified this change indeed reverts to the previous xprv in https://github.com/bitcoin/bips/pull/1600/files#diff-eae7a61b6d2a0b6091c1ce04618f216cbb871d987b985ba712de89e04014654cL235.


===HEX===
Application number: 128169'
Expand Down Expand Up @@ -438,8 +439,7 @@ BIP32, BIP39

* 1.0 (2020-07)
* 2.0.0 (2024-09-22)
* Swap chain code and private key bytes in application 32' for consistentcy with BIP-32 (major change)
* Correct derived entropy for application 128169' test vector (major change)
* Correct derived entropy for application 707764' test vector (bugfix)
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@scgbckbone scgbckbone Oct 4, 2024

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@akarve I assume this was bug in application number ? you mentioned 128169' in previous PR BUT wrong entropy was in 707764'. I see no breaking changes in hex app

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@akarve akarve Oct 7, 2024

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The only vector that needs correction as of my simplified PR #1679 is Hex (128169').

If somehow an extant implementation got the old test vector to work this correction would be a breaking change but I agree that if the correct BIP 85 algo is used then this is non-breaking :)

* Clarify big endian serialization
* Add the Portuguese language (9') to application 39'
* Add dice application 89101'
Expand Down