gmp convert fix

Author: andkom

src/Crypto/PublicKey.php

@@ -178,14 +178,14 @@ static public function parse(string $data): self
      */
     public function serialize(): string
     {
-        $x = Utils::gmpToBin($this->x);
+        $x = Utils::gmpToBin($this->x, 32);
 
         if ($this->isCompressed()) {
             $prefix = $this->wasOdd ? static::PREFIX_COMPRESSED_ODD : static::PREFIX_COMPRESSED_EVEN;
             $y = '';
         } else {
             $prefix = static::PREFIX_UNCOMPRESSED;
-            $y = Utils::gmpToBin($this->y);
+            $y = Utils::gmpToBin($this->y, 32);
         }
 
         return $prefix . $x . $y;

src/Utils.php

@@ -70,13 +70,44 @@ static public function hexToHash(string $hex): string
      * @param \GMP $gmp
      * @return string
      */
-    static public function gmpToBin(\GMP $gmp): string
+    static public function gmpToHex(\GMP $gmp): string
     {
         $hex = gmp_strval($gmp, 16);
+
         if (strlen($hex) % 2 != 0) {
             $hex = '0' . $hex;
         }
-        return hex2bin($hex);
+
+        return $hex;
+    }
+
+    /**
+     * @param string $hex
+     * @return string
+     */
+    static public function hexToGmp(string $hex): \GMP
+    {
+        return gmp_init($hex, 16);
+    }
+
+    /**
+     * @param \GMP $gmp
+     * @return string
+     */
+    static public function gmpToBin(\GMP $gmp, int $bytes = null): string
+    {
+        $bin = hex2bin(static::gmpToHex($gmp));
+
+        if ($bytes !== null) {
+            $size = strlen($bin);
+            if ($size < $bytes) {
+                $bin = str_pad($bin, $bytes, chr(0), STR_PAD_LEFT);
+            } elseif ($size > $bytes) {
+                $bin = substr($bin, 0, $bytes);
+            }
+        }
+
+        return $bin;
     }
 
     /**
@@ -85,6 +116,6 @@ static public function gmpToBin(\GMP $gmp): string
      */
     static public function binToGmp(string $data): \GMP
     {
-        return gmp_init(bin2hex($data), 16);
+        return static::hexToGmp(bin2hex($data));
     }
 }