From defc917dbcd2cf0f2879da642b537a09a19a6df4 Mon Sep 17 00:00:00 2001
From: dpad85 <5765435+dpad85@users.noreply.github.com>
Date: Thu, 24 Mar 2022 17:29:19 +0100
Subject: [PATCH] Add support for kmp node key generation

This is needed for the migration to kmp
---
 .../main/scala/fr/acinq/eclair/crypto/KeyManager.scala |  2 ++
 .../scala/fr/acinq/eclair/crypto/LocalKeyManager.scala |  9 +++++++++
 .../fr/acinq/eclair/crypto/LocalKeyManagerSpec.scala   | 10 +++++++++-
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/eclair-core/src/main/scala/fr/acinq/eclair/crypto/KeyManager.scala b/eclair-core/src/main/scala/fr/acinq/eclair/crypto/KeyManager.scala
index d25c5c1e9..443508444 100644
--- a/eclair-core/src/main/scala/fr/acinq/eclair/crypto/KeyManager.scala
+++ b/eclair-core/src/main/scala/fr/acinq/eclair/crypto/KeyManager.scala
@@ -31,6 +31,8 @@ trait KeyManager {
 
   def nodeId: PublicKey
 
+  def kmpNodeKey: DeterministicWallet.ExtendedPrivateKey
+
   def fundingPublicKey(keyPath: DeterministicWallet.KeyPath): ExtendedPublicKey
 
   def revocationPoint(channelKeyPath: DeterministicWallet.KeyPath): ExtendedPublicKey
diff --git a/eclair-core/src/main/scala/fr/acinq/eclair/crypto/LocalKeyManager.scala b/eclair-core/src/main/scala/fr/acinq/eclair/crypto/LocalKeyManager.scala
index 0de36c9dc..ae2b27a05 100644
--- a/eclair-core/src/main/scala/fr/acinq/eclair/crypto/LocalKeyManager.scala
+++ b/eclair-core/src/main/scala/fr/acinq/eclair/crypto/LocalKeyManager.scala
@@ -40,6 +40,14 @@ object LocalKeyManager {
     case Block.RegtestGenesisBlock.hash | Block.TestnetGenesisBlock.hash => DeterministicWallet.hardened(46) :: DeterministicWallet.hardened(0) :: Nil
     case Block.LivenetGenesisBlock.hash => DeterministicWallet.hardened(47) :: DeterministicWallet.hardened(0) :: Nil
   }
+
+  // WARNING: if you change this path, you will change your node id even if the seed remains the same!!!
+  // Note that the node path and the above channel path are on different branches so even if the
+  // node key is compromised there is no way to retrieve the wallet keys
+  def kmpNodeKeyBasePath(chainHash: ByteVector32) = (chainHash: @unchecked) match {
+    case Block.RegtestGenesisBlock.hash | Block.TestnetGenesisBlock.hash => DeterministicWallet.hardened(48) :: DeterministicWallet.hardened(0) :: Nil
+    case Block.LivenetGenesisBlock.hash => DeterministicWallet.hardened(50) :: DeterministicWallet.hardened(0) :: Nil
+  }
 }
 
 /**
@@ -53,6 +61,7 @@ class LocalKeyManager(seed: ByteVector, chainHash: ByteVector32) extends KeyMana
 
   override val nodeKey = DeterministicWallet.derivePrivateKey(master, LocalKeyManager.nodeKeyBasePath(chainHash))
   override val nodeId = nodeKey.publicKey
+  override val kmpNodeKey = DeterministicWallet.derivePrivateKey(master, LocalKeyManager.kmpNodeKeyBasePath(chainHash))
 
   private val privateKeys: LoadingCache[KeyPath, ExtendedPrivateKey] = CacheBuilder.newBuilder()
     .maximumSize(6 * 200) // 6 keys per channel * 200 channels
diff --git a/eclair-core/src/test/scala/fr/acinq/eclair/crypto/LocalKeyManagerSpec.scala b/eclair-core/src/test/scala/fr/acinq/eclair/crypto/LocalKeyManagerSpec.scala
index 5f477273d..eb39704c9 100644
--- a/eclair-core/src/test/scala/fr/acinq/eclair/crypto/LocalKeyManagerSpec.scala
+++ b/eclair-core/src/test/scala/fr/acinq/eclair/crypto/LocalKeyManagerSpec.scala
@@ -18,7 +18,7 @@ package fr.acinq.eclair.crypto
 
 import fr.acinq.bitcoin.scala.Crypto.{PrivateKey, PublicKey}
 import fr.acinq.bitcoin.scala.DeterministicWallet.KeyPath
-import fr.acinq.bitcoin.scala.{Block, ByteVector32, DeterministicWallet}
+import fr.acinq.bitcoin.scala.{Block, ByteVector32, DeterministicWallet, MnemonicCode}
 import fr.acinq.eclair.TestConstants
 import fr.acinq.eclair.channel.ChannelVersion
 import org.scalatest.funsuite.AnyFunSuite
@@ -34,6 +34,14 @@ class LocalKeyManagerSpec extends AnyFunSuite {
     assert(keyManager.nodeId == PublicKey(hex"02a051267759c3a149e3e72372f4e0c4054ba597ebfd0eda78a2273023667205ee"))
   }
 
+  test("generate the same KMP node id from the same seed") {
+    // if this test breaks it means that we will generate a different KMP node id from
+    // the same seed, which could be a problem during migration from eclair-core to kmp
+    val seed = MnemonicCode.toSeed("sock able evoke work output half bamboo energy simple fiber unhappy afford", passphrase = "")
+    val keyManager = new LocalKeyManager(seed, Block.TestnetGenesisBlock.hash)
+    assert(keyManager.kmpNodeKey.publicKey == PublicKey(hex"022b49d4ab3342ada31d79d2a57ceaa2e8f573277552a44433bc8a4ee5b945085d"))
+  }
+
   test("generate the same secrets from the same seed") {
     // data was generated with eclair 0.3 
     val seed = hex"17b086b228025fa8f4416324b6ba2ec36e68570ae2fc3d392520969f2a9d0c1501"