HierarchicalKey::derivePath - accept absolute paths if the key is the…

… root key
Bit-Wasp · Apr 16, 2021 · 39955be · 39955be
1 parent bfea639
commit 39955be
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Showing 2 changed files with 59 additions and 2 deletions.
diff --git a/src/Key/Deterministic/HierarchicalKey.php b/src/Key/Deterministic/HierarchicalKey.php
@@ -320,8 +320,17 @@ public function deriveChild(int $sequence): HierarchicalKey
      */
     public function derivePath(string $path): HierarchicalKey
     {
+        if ($path == "") {
+            throw new \InvalidArgumentException("Path cannot be empty!");
+        }
+
         $sequences = new HierarchicalKeySequence();
-        $parts = $sequences->decodeRelative($path);
+        if ($this->depth == 0 && ($path[0] == 'm' || $path[0] == 'M')) {
+            list($retainPrivate, $parts) = $sequences->decodeAbsolute($path);
+        } else {
+            $retainPrivate = true;
+            $parts = $sequences->decodeRelative($path);
+        }
         $numParts = count($parts);
 
         $key = $this;
@@ -336,7 +345,9 @@ public function derivePath(string $path): HierarchicalKey
                 }
             }
         }
-
+        if (!$retainPrivate) {
+            $key = $key->withoutPrivateKey();
+        }
         return $key;
     }
 

diff --git a/tests/Key/Deterministic/HierarchicalKeyTest.php b/tests/Key/Deterministic/HierarchicalKeyTest.php
@@ -189,6 +189,52 @@ public function testDerivePath(EcAdapterInterface $ecAdapter)
         $this->assertEquals("xprvA4A9CuBXhdBtCaLxwrw64Jaran4n1rgzeS5mjH47Ds8V67uZS8tTkG8jV3BZi83QqYXPcN4v8EjK2Aof4YcEeqLt688mV57gF4j6QZWdP9U", $bip44ChildKey->toExtendedKey($network));
     }
 
+    /**
+     * @dataProvider getEcAdapters
+     * @param EcAdapterInterface $ecAdapter
+     */
+    public function testMasterKeyCanDeriveAbsolutePaths(EcAdapterInterface $ecAdapter)
+    {
+        $xPrv = 'xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi';
+        $hdFactory = new HierarchicalKeyFactory($ecAdapter);
+        $key = $hdFactory->fromExtended($xPrv, $this->network);
+        $derivPriv = $key->derivePath("m/0'");
+        $this->assertTrue($derivPriv->isPrivate());
+        $this->assertEquals("xprv9uHRZZhk6KAJC1avXpDAp4MDc3sQKNxDiPvvkX8Br5ngLNv1TxvUxt4cV1rGL5hj6KCesnDYUhd7oWgT11eZG7XnxHrnYeSvkzY7d2bhkJ7", $derivPriv->toExtendedPrivateKey($this->network));
+        $this->assertEquals("xpub68Gmy5EdvgibQVfPdqkBBCHxA5htiqg55crXYuXoQRKfDBFA1WEjWgP6LHhwBZeNK1VTsfTFUHCdrfp1bgwQ9xv5ski8PX9rL2dZXvgGDnw", $derivPriv->toExtendedPublicKey($this->network));
+
+        $derivPriv = $key->derivePath("0'");
+        $this->assertTrue($derivPriv->isPrivate());
+        $this->assertEquals("xprv9uHRZZhk6KAJC1avXpDAp4MDc3sQKNxDiPvvkX8Br5ngLNv1TxvUxt4cV1rGL5hj6KCesnDYUhd7oWgT11eZG7XnxHrnYeSvkzY7d2bhkJ7", $derivPriv->toExtendedPrivateKey($this->network));
+        $this->assertEquals("xpub68Gmy5EdvgibQVfPdqkBBCHxA5htiqg55crXYuXoQRKfDBFA1WEjWgP6LHhwBZeNK1VTsfTFUHCdrfp1bgwQ9xv5ski8PX9rL2dZXvgGDnw", $derivPriv->toExtendedPublicKey($this->network));
+
+        $derivPub = $key->derivePath("M/0'");
+        $this->assertFalse($derivPub->isPrivate());
+        $this->assertEquals("xpub68Gmy5EdvgibQVfPdqkBBCHxA5htiqg55crXYuXoQRKfDBFA1WEjWgP6LHhwBZeNK1VTsfTFUHCdrfp1bgwQ9xv5ski8PX9rL2dZXvgGDnw", $derivPub->toExtendedPublicKey($this->network));
+    }
+
+    public function testChildCannotDeriveAbsolutePaths()
+    {
+        $ecAdapter = Bitcoin::getEcAdapter();
+        $xPrv = 'xprv9uHRZZhk6KAJC1avXpDAp4MDc3sQKNxDiPvvkX8Br5ngLNv1TxvUxt4cV1rGL5hj6KCesnDYUhd7oWgT11eZG7XnxHrnYeSvkzY7d2bhkJ7';
+        $hdFactory = new HierarchicalKeyFactory($ecAdapter);
+        $key = $hdFactory->fromExtended($xPrv, $this->network);
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage("Only relative paths accepted");
+        $key->derivePath("m/0'");
+    }
+
+    public function testChildCannotDeriveAbsolutePathsPublic()
+    {
+        $ecAdapter = Bitcoin::getEcAdapter();
+        $xPrv = 'xprv9uHRZZhk6KAJC1avXpDAp4MDc3sQKNxDiPvvkX8Br5ngLNv1TxvUxt4cV1rGL5hj6KCesnDYUhd7oWgT11eZG7XnxHrnYeSvkzY7d2bhkJ7';
+        $hdFactory = new HierarchicalKeyFactory($ecAdapter);
+        $key = $hdFactory->fromExtended($xPrv, $this->network);
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage("Only relative paths accepted");
+        $key->derivePath("M/0'");
+    }
+
     /**
      * @dataProvider getEcAdapters
      * @param EcAdapterInterface $ecAdapter