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Fix Electrum v1 seed/key derivation and unify NFKD normalization - #13

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Fix Electrum v1 seed/key derivation and unify NFKD normalization#13
edtubbs with Copilot wants to merge 14 commits into
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Copilot AI commented Feb 16, 2026 •
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Electrum v1 mnemonic support had several correctness issues: seed function applied stretch_key prematurely (seed should be raw decoded bytes), key derivation used compressed keys (v1 requires uncompressed), and normalization used a custom ASCII-only function instead of the existing utf8proc NFKD pipeline. All outputs verified against bip-utils ElectrumV1 class.

Seed derivation (src/bip39.c)

  • dogecoin_seed_from_electrum_v1_mnemonic: returns raw 16-byte decoded seed, no stretching — e.g. "hardly point goal..." → 8edad31a95e7d59f8837667510d75a4d
  • dogecoin_mnemonic_is_electrum_seed: returns 0/-1 (was 1/0), matching all other bip39 functions
  • Replaced electrum_prepare_seed_ascii + manual lowercase loops with single utf8proc_map() call using NFKD | CASEFOLD
  • strtok → strtok_r for OP-TEE (aarch64 TrustZone) compatibility
  • #define UTF8PROC_STATIC to fix __imp_utf8proc_map linker errors on Windows/MinGW

Key derivation (src/key.c)

  • electrum_v1_derive_privkey32: performs stretch_key internally (100k SHA256 on hex seed), derives child keys via double-SHA256 tweak on raw 64-byte MPK
  • Uses uncompressed pubkeys throughout (v1 requirement)

CLI (src/cli/such.c)

  • mnemonic_to_key -l: uncompressed WIF (prefix 6, not Q)
  • mnemonic_to_addresses -l: uncompressed pubkey P2PKH addresses

Tests

  • Seed decode vectors in bip39_tests.c, key/address vectors in key_tests.c (no overlap)
  • Both "hardly point goal..." and "like just love..." mnemonics verified against bip-utils
# Reference verification
from bip_utils import ElectrumV1MnemonicDecoder, ElectrumV1SeedGenerator, ElectrumV1
mnemonic = "hardly point goal hallway patience key stone difference ready caught listen fact"
entropy = ElectrumV1MnemonicDecoder().Decode(mnemonic)  # 8edad31a95e7d59f8837667510d75a4d
seed = ElectrumV1SeedGenerator(mnemonic).Generate()
e = ElectrumV1.FromSeed(seed)
e.GetPrivateKey(0, 0).ToWif()    # 6J...
e.GetPrivateKey(0, 0).PublicKey().ToAddress()  # D5H1b4A...

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@edtubbs
Fix Electrum v1 seed derivation, key derivation, and update tests
e706b46 
- Remove extra SHA256 pre-hash in dogecoin_seed_from_electrum_v1_mnemonic
  (Electrum v1 passes hex string bytes directly to stretch function)
- Fix electrum_v1_derive_privkey32 to use raw binary MPK bytes (64 bytes)
  instead of hex string (128 chars) and double SHA256 instead of single
- Add test vector: seed='8edad31a95e7d59f8837667510d75a4d' mnemonic=
  'hardly point goal hallway patience key stone difference ready caught
  listen fact'
- Update expected values for 'like just love...' test vector
- Add key derivation test for proper v1 12-word mnemonic

Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
Copilot AI changed the title [WIP] Fix dogecoin_seed_from_electrum_v1_mnemonic and update test Fix Electrum v1 seed and key derivation to match original algorithm Feb 16, 2026
Copilot AI requested a review from edtubbs February 16, 2026 23:50
@edtubbs
Move stretching from seed function to key derivation
fe42755 
The seed IS the raw decoded value (e.g. 8edad31a95e7d59f8837667510d75a4d).
stretch_key() belongs in key derivation, not seed storage, matching
original Electrum v1 Python implementation.

Changes:
- dogecoin_seed_from_electrum_v1_mnemonic: returns raw decoded 16-byte
  seed directly, no stretching, no fallback for non-v1 mnemonics
- electrum_v1_derive_privkey32: now does stretch_key internally (convert
  16-byte seed to hex, 100k SHA256 iterations) before key derivation
- Remove unused electrum_v1_stretch from bip39.c
- Update all tests with correct expected seed values
- Derived keys unchanged (stretching just moved to correct location)

Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
Copilot AI changed the title Fix Electrum v1 seed and key derivation to match original algorithm Fix Electrum v1: seed is raw decoded value, move stretch_key to key derivation Feb 17, 2026
Copilot AI and others added 2 commits February 17, 2026 03:06
@edtubbs
Use uncompressed keys for Electrum v1 per bip-utils reference
fd65c17 
Electrum v1 uses uncompressed public keys for both WIF encoding and
P2PKH address generation, as documented in the bip-utils reference:
  https://bip-utils.readthedocs.io/en/latest/bip_utils/electrum/electrum_v1.html

Changes:
- CLI mnemonic_to_key with -l: uncompressed WIF (starts with '6' not 'Q')
- CLI mnemonic_to_addresses with -l: uncompressed pubkey P2PKH addresses
- Test: add bip-utils reference vectors verifying addresses match exactly
- All output verified against pip install bip-utils ElectrumV1 class

Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
@edtubbs
Zero-initialize wif_payload buffer before use
791da11 
Address code review feedback: zero-initialize wif_payload to prevent
potential information leakage before setting version byte and privkey.

Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
Copilot AI changed the title Fix Electrum v1: seed is raw decoded value, move stretch_key to key derivation Fix Electrum v1: raw seed, stretch in key derivation, uncompressed keys Feb 17, 2026
@edtubbs
Add bip-utils bounce test for 'like just love...' mnemonic
d3ec0c9 
Verified against pip install bip-utils ElectrumV1 class:
  entropy: 00285dfe00285e0100285e0400285e07
  child key[0]: b9a83170bfc2a80219d3d4b789acf145...
  address[0]: DJqkqMLLkio821TrxpZxUDhVFaSDR7VeWz

All values match bip-utils reference exactly.

Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
@edtubbs
edtubbs force-pushed the 0.1.5-dev-electrum-seed branch from bc8b234 to b6b96a7 Compare February 17, 2026 03:29
@edtubbs
Replace strtok with manual tokenizer for OP-TEE compatibility
b7abcda 
strtok is not available in the OP-TEE (TrustZone) aarch64 environment.
Replace with a simple pointer-walk tokenizer that splits on spaces
without depending on the C standard library's strtok.

Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
Copilot AI changed the title Fix Electrum v1: raw seed, stretch in key derivation, uncompressed keys Fix Electrum v1 mnemonic: correct seed/key derivation, uncompressed keys, OP-TEE compat Feb 17, 2026
@edtubbs
Use strtok_r instead of manual tokenizer in electrum_v1_decode_mnemonic
cb2ceca 
strtok_r is thread-safe and already available in OP-TEE (unlike strtok).
The repo already maps strtok_r to strtok_s for MSVC compatibility.

Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
Copilot AI changed the title Fix Electrum v1 mnemonic: correct seed/key derivation, uncompressed keys, OP-TEE compat Fix Electrum v1 seed derivation, key encoding, and OP-TEE link error Feb 17, 2026
@edtubbs
edtubbs force-pushed the 0.1.5-dev-electrum-seed branch from b6b96a7 to 9f23b1c Compare February 17, 2026 04:51
@edtubbs
Document v1 12-word requirement and ASCII/NFKD normalization equivalence
ace31de 
Verified against bip-utils:
- 12 words is a strict v1 requirement (ElectrumV1MnemonicConst.MNEMONIC_WORD_NUM == [12])
- ASCII lowercase == NFKD + lowercase for the English-only v1 wordlist
  (all 1626 words are pure ASCII, so NFKD is a no-op)

Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
Copilot AI changed the title Fix Electrum v1 seed derivation, key encoding, and OP-TEE link error Fix Electrum v1: correct seed/key derivation, uncompressed encoding, OP-TEE link fix Feb 17, 2026
Copilot AI and others added 2 commits February 17, 2026 19:14
@edtubbs
Plan: Fix return convention, use utf8proc_NFKD, remove test overlap
2107084 
Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
@edtubbs
Remove duplicate electrum tests between key_tests and bip39_tests
d347866 
- key_tests: Remove "alpha bravo" rejection test (covered in bip39_tests)
- key_tests: Remove raw seed hex assertions (covered in bip39_tests)
- key_tests: Keep unique key derivation and address tests
- bip39_tests: Remove duplicate "alpha bravo" with passphrase test

Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
Copilot AI changed the title Fix Electrum v1: correct seed/key derivation, uncompressed encoding, OP-TEE link fix Fix Electrum v1 seed derivation, key derivation, and normalize API conventions Feb 17, 2026
@edtubbs
Use utf8proc_map NFKD+CASEFOLD instead of manual lowercase loops
6fcc93f 
Replace all utf8proc_NFKD() + manual lowercase loop patterns with a
single utf8proc_map() call using NFKD + CASEFOLD flags. Unicode
case-folding is a superset of lowercasing and handles it correctly.

Also removes the now-unused electrum_prepare_seed_ascii function.

Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
Copilot AI changed the title Fix Electrum v1 seed derivation, key derivation, and normalize API conventions Fix Electrum v1 seed derivation, key derivation, and unify NFKD normalization Feb 17, 2026
@edtubbs
edtubbs force-pushed the 0.1.5-dev-electrum-seed branch from 9f23b1c to bcd590a Compare February 17, 2026 19:43
@edtubbs
Fix Windows CI linker error: define UTF8PROC_STATIC in bip39.c
76aef8c 
On Windows (MinGW), utf8proc.h decorates functions with
__declspec(dllimport) unless UTF8PROC_STATIC or UTF8PROC_EXPORTS
is defined. Since libdogecoin links utf8proc statically, bip39.c
needs UTF8PROC_STATIC to avoid __imp_utf8proc_map linker errors.

Fixes: undefined reference to `__imp_utf8proc_map` on x86_64-win
and i686-win CI builds.

Co-authored-by: edtubbs <84785904+edtubbs@users.noreply.github.com>
Copilot AI changed the title Fix Electrum v1 seed derivation, key derivation, and unify NFKD normalization Fix Electrum v1 seed/key derivation and unify NFKD normalization Feb 18, 2026
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