BIP32Key class

src/Bitcoin/BIP32Key.php

@@ -0,0 +1,124 @@
+<?php
+
+namespace Blocktrail\SDK\Bitcoin;
+use BitWasp\BitcoinLib\BIP32;
+
+/**
+ * Class BIP32Key
+ *
+ * Container for a BIP32 key and path
+ */
+class BIP32Key {
+    /**
+     * @var string
+     */
+    private $key;
+
+    /**
+     * @var BIP32Path
+     */
+    private $path;
+
+    /**
+     * @var string|null
+     */
+    private $publicKey = null;
+
+    /**
+     * @var BIP32Key[]
+     */
+    private $derivations = [];
+
+    /**
+     * @param string|array  $key        if it's an array then it will be split into $key and $path
+     * @param string|null   $path
+     * @throws \Exception
+     */
+    public function __construct($key, $path = null) {
+        if (is_array($key) && count($key) == 2) {
+            $this->key = $key[0];
+            $this->path = BIP32Path::path($key[1]);
+        } else if (is_string($key) && is_string($path) && strlen($key) && strlen($path)) {
+            $this->key = $key;
+            $this->path = BIP32Path::path($path);
+        } else {
+            throw new \Exception("Bad input");
+        }
+    }
+
+    /**
+     * static method to initialize class
+     *
+     * @param string|array  $key
+     * @param string|null   $path
+     * @return BIP32Key
+     */
+    public static function create($key, $path = null) {
+        return new BIP32Key($key, $path);
+    }
+
+    /**
+     * @return string
+     */
+    public function key() {
+        return $this->key;
+    }
+
+    /**
+     * @return BIP32Path
+     */
+    public function path() {
+        return $this->path;
+    }
+
+    /**
+     * get tuple of the key and path, the way BitcoinLib likes it
+     *
+     * @return array        [key, path]
+     */
+    public function tuple() {
+        return [$this->key, (string)$this->path];
+    }
+
+    /**
+     * @return BIP32Path
+     */
+    public function bip32Path() {
+        return BIP32Path::path($this->path);
+    }
+
+    /**
+     * build child key
+     *
+     * @param string|BIP32Path  $path
+     * @return BIP32Key
+     * @throws \Exception
+     */
+    public function buildKey($path) {
+        if (!isset($this->derivations[(string)$path])) {
+            $key = BIP32::build_key($this->tuple(), (string)$path);
+            $this->derivations[(string)$path] = $key;
+        }
+
+        return new BIP32Key($this->derivations[(string)$path]);
+    }
+
+    /**
+     * get the plain public key for the current BIP32 key
+     *
+     * @return string
+     */
+    public function publicKey() {
+        // if this is a BIP32 Private key then we first build the public key
+        //  that way it will be cached nicely
+        if (!$this->path->isPublicPath()) {
+            return $this->buildKey($this->path->publicPath())->publicKey();
+        } else {
+            if (is_null($this->publicKey)) {
+                $this->publicKey = BIP32::extract_public_key($this->tuple());
+            }
+
+            return $this->publicKey;
+        }
+    }
+}