diff --git a/composer.json b/composer.json
index b28110e..f47b1c8 100644
--- a/composer.json
+++ b/composer.json
@@ -9,7 +9,6 @@
             "email": "alk03073135@gmail.com"
         }
     ],
-    "minimum-stability": "dev",
     "require-dev": {
         "phpunit/phpunit": "^6.1"
     },
diff --git a/src/Transaction.php b/src/Transaction.php
index 33c6206..d684512 100644
--- a/src/Transaction.php
+++ b/src/Transaction.php
@@ -285,7 +285,9 @@ public function sign(string $privateKey)
     {
         $txHash = $this->hash(false);
         $privateKey = $this->secp256k1->keyFromPrivate($privateKey, 'hex');
-        $signature = $privateKey->sign($txHash);
+        $signature = $privateKey->sign($txHash, [
+            'canonical' => true
+        ]);
         $r = $signature->r;
         $s = $signature->s;
         $v = $signature->recoveryParam + 35;
@@ -321,6 +323,8 @@ public function hash($includeSignature=false)
         if ($includeSignature) {
             $txData = $this->txData;
         } else {
+            $rawTxData = $this->txData;
+
             if ($chainId && $chainId > 0) {
                 $v = (int) $chainId;
                 $this->offsetSet('r', '');
@@ -336,6 +340,7 @@ public function hash($includeSignature=false)
                     $txData[$key] = $data;
                 }
             }
+            $this->txData = $rawTxData;
         }
         $serializedTx = $this->rlp->encode($txData)->toString('utf8');
 
diff --git a/test/unit/TransactionTest.php b/test/unit/TransactionTest.php
index 57d7382..d0e80be 100644
--- a/test/unit/TransactionTest.php
+++ b/test/unit/TransactionTest.php
@@ -206,6 +206,21 @@ public function testSerialize()
      */
     public function testEIP155()
     {
+        // test signing data
+        $transaction = new Transaction([
+            'nonce' => '0x09',
+            'to' => '0x3535353535353535353535353535353535353535',
+            'gas' => '0x5208',
+            'gasPrice' => '0x4a817c800',
+            'value' => '0xde0b6b3a7640000',
+            'chainId' => 1,
+            'data' => ''
+        ]);
+        $transaction['r'] = '';
+        $transaction['s'] = '';
+        $transaction['v'] = 1;
+        $this->assertEquals('ec098504a817c800825208943535353535353535353535353535353535353535880de0b6b3a764000080018080', $transaction->serialize()->toString('hex'));
+
         $transaction = new Transaction([
             'nonce' => '0x09',
             'to' => '0x3535353535353535353535353535353535353535',