HD wallet

[UdjinM6]

HD wallet for Dash Core 0.12.2.x+

• minimal BIP32 changes backported from Bitcoin upstream;
• BIP44 derivation scheme;
• BIP39 mnemonic and mnemonic passphrase can be used to create HD wallet (optional, using random mnemonic and mnemonic passphrase if mnemonic was not specified by the user explicitly);
• only seed is stored, all keys are derived on the fly (seed is stored encrypted if wallet is locked).

Note: mnemonic is not stored and can't be recovered.

[taw00]

Whoa. You can do this in core?

[SCDeveloper]

Will mean everyone needs to export and reimport their privkeys to the new wallet structure. But I can confirm this works as it is in https://github.com/duality-solutions/dynamic

[akijuh]

What that HD stands for?

[UdjinM6]

@SCDeveloper Yep, there will be a need in some migration for old users (optional though). Another option would be to create a completely new wallet and then simply send all funds from an old wallet to a new one. This way ALL keys will be recoverable. And yes, that repo was where I started from first and was able to compile wallet actually after resolving some conflicts. But I wasn't happy with way too many changes all over the place due to embedded refactoring, so had to backport upstream changes selectively instead. Anyway, thanks for the starting point :)

@akijuh Hierarchical Deterministic (HD) Wallets https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki

[UdjinM6]

This should be ready for review and testing now.

[UdjinM6]

Changes:

• top up keypool on hd wallet encryption (fix tests);
• backport, fix and slightly refactor bitcoin core 9294 and 10235 (hd chain split).

NOTE: This breaks compatibility with hd wallets created on previous commits. If you have such wallet, apply this patch locally and run it once:

diff --git a/src/hdchain.h b/src/hdchain.h
index 6cdc7c831..b0fee515b 100644
--- a/src/hdchain.h
+++ b/src/hdchain.h
@@ -29,7 +29,17 @@ public:
         READWRITE(vchSeed);
         READWRITE(id);
         READWRITE(nExternalChainCounter);
-        READWRITE(nInternalChainCounter);
+        if (ser_action.ForRead()) {
+            try {
+                READWRITE(nInternalChainCounter);
+            }
+            catch (std::ios_base::failure&) {
+                nInternalChainCounter = 0;
+            }
+        }
+        else {
+            READWRITE(nInternalChainCounter);
+        }
     }
 
     bool SetNull();

[UdjinM6]

Wallet should now store mnemonic/mnemonicpassphrase.

NOTE: This is incompatible with previous hd wallets once again, run-once patch is should be similar to the one above but it's not(?).

EDIT: err... smth wasn't quite right with that commit, so I had to force push, sorry :/
EDIT2: and again... also patch for wallets on old commit doesn't seem to work for some reason... investigating..
EDIT3: ok, so it's smth with vector serialization I guess. Don't want to dig too much into it, so let's just accept that it's incompatible 😇 dump hdseed using old build and start new wallet using new build and -hdseed if you need one (might also require to run keypoolrefill to increase number of known addresses to the size of the old wallet and rescan).

[UdjinM6]

Rebased to resolve merge conflict after #1473 (around this line https://github.com/dashpay/dash/pull/1405/files#diff-8bdec64a6a2adb83b9696e5ca6d5522bR1282)

[Imebeez]