Activate BIP44 wallet derivation (#124)

* Add BIP32 path derivation foundation

* Add HD wallet schema metadata

* Add provisional BIP44 coin type metadata

* Activate BIP44 wallet derivation

* wallet: scan BIP44 restore depth per branch

* wallet: widen default BIP44 restore lookahead

---------

Co-authored-by: Gilcimar Duarte <ti@gpm.infra>

1 files changed, 13 insertions, 1 deletions

diff --git a/src/bip32.h b/src/bip32.h
index a029444..e9862d5 100644
--- a/src/bip32.h
+++ b/src/bip32.h
@@ -5,7 +5,7 @@
 //
 // This module is deliberately independent from wallet.dat and GUI code. It is
 // the auditable foundation: mnemonic generation/validation, seed derivation,
-// and hardened private child derivation over secp256k1.
+// and private child derivation over secp256k1.
 
 #ifndef BITFLASH_BIP32_H
 #define BITFLASH_BIP32_H
@@ -16,6 +16,8 @@
 namespace bitflash
 {
 
+static const unsigned int BIP32_HARDENED = 0x80000000U;
+
 struct BIP32PrivateNode
 {
     std::vector<unsigned char> privateKey; // 32-byte scalar
@@ -43,6 +45,16 @@ bool BIP32MasterFromSeed(const std::vector<unsigned char>& seed,
                          BIP32PrivateNode& nodeOut,
                          std::string& errorOut);
 
+bool BIP32DeriveChild(const BIP32PrivateNode& parent,
+                      unsigned int childNumber,
+                      BIP32PrivateNode& childOut,
+                      std::string& errorOut);
+
+bool BIP32DerivePath(const BIP32PrivateNode& root,
+                     const std::vector<unsigned int>& path,
+                     BIP32PrivateNode& nodeOut,
+                     std::string& errorOut);
+
 bool BIP32DeriveHardenedChild(const BIP32PrivateNode& parent,
                               unsigned int childIndex,
                               BIP32PrivateNode& childOut,