ionux · ionux · Apr 27, 2018 · Feb 2, 2018 · Feb 9, 2018 · Feb 9, 2018
diff --git a/src/Key.php b/src/Key.php
@@ -148,9 +148,18 @@ public function parseUncompressedPublicKey($pubkey)
      */
     public function parseCompressedPublicKey($pubkey, $returnHex = false)
     {
-        $parsedVal = (substr($pubkey, 0, 2) == '02' || substr($pubkey, 0, 2) == '03') ? $this->prepAndClean($this->calcYfromX(substr($pubkey, 2), substr($pubkey, 0, 2))) : $this->prepAndClean($pubkey);
-
-        return ($returnHex === false) ? $parsedVal : $this->encodeHex($parsedVal);            
+        $prefix = substr($pubkey, 0, 2);
+
+        if ($prefix !== '02' && $prefix !== '03') {
+            return $this->prepAndClean($pubkey);
+        }
+
+        $pointX = substr($pubkey, 2);
+        $pointY = substr($this->calcYfromX($pointX, $prefix), 2);
+
+        $parsedValue = $this->prepAndClean($pointX . $pointY);
+
+        return ($returnHex === false) ? $parsedValue : $this->encodeHex($parsedValue);
     }
 
     /**

diff --git a/src/Point.php b/src/Point.php
@@ -299,8 +299,9 @@ public function calcYfromX($x_coord, $compressed_bit)
             $c = $this->Subtract($this->decodeHex($this->addHexPrefix($compressed_bit)), '2');
             $a = $this->Modulo($this->Add($this->PowMod($x, '3', $this->p), '7'), $this->p);
             $y = $this->PowMod($a, $this->Divide($this->Add($this->p, '1'), '4'), $this->p);
+            $y = ($this->Modulo($y, '2') != $c) ? $this->decodeHex($this->Modulo($this->Multiply('-1', $y), $this->p)) : $this->decodeHex($y);
 
-            return ($this->Modulo($y, '2') != $c) ? $this->decodeHex($this->Modulo($this->Multiply('-1', $y), $this->p)) : $this->decodeHex($y);
+            return $this->encodeHex($y);
         } catch (\Exception $e) {
             throw $e;
         }

diff --git a/tests/PointTest.php b/tests/PointTest.php
@@ -218,12 +218,11 @@ public function testCalcYfromX()
 
         $x = '0x9970eb90fc5fb04d5c63201e6124b4c77957ea79ebc129f07dca7b30da54230c';
         $y = '0x6ee4fc6f37788608b16a0cb81968176c1b2042c65515d4d4053a1d390e62433c';
-        $y_dec = '50158996713404002186761311168531259625706655107568015898414438196527281357628';
         $compressed_bit = '0x02';
 
         $calc_y = $this->mock->calcYfromX($x, $compressed_bit);
 
         $this->assertNotNull($calc_y);
-        $this->assertEquals($y_dec, $calc_y);
+        $this->assertEquals($y, $calc_y);
     }
 }