diff --git a/src/Utility.php b/src/Utility.php
index 9f3a527..440fa5d 100644
--- a/src/Utility.php
+++ b/src/Utility.php
@@ -41,17 +41,49 @@ public function verifyPaymentSignature($attributes)
         }
 
         $secret = Api::getSecret();
+        
+        // If we're using OAuth token authentication, check if secret is provided in attributes
+        if (empty($secret) && Api::getToken() !== null)
+        {
+            if (isset($attributes['secret']) === true)
+            {
+                $secret = $attributes['secret'];
+            }
+            else
+            {
+                throw new Errors\SignatureVerificationError(
+                    'When using OAuth authentication, you must provide the secret as an attribute for signature verification.');
+            }
+        }
 
         self::verifySignature($payload, $actualSignature, $secret);
     }
 
-    public function verifyWebhookSignature($payload, $actualSignature, $secret)
+    public function verifyWebhookSignature($payload, $actualSignature, $secret = null)
     {
+        // If secret isn't provided and we're using OAuth token authentication
+        if ($secret === null)
+        {
+            $secret = Api::getSecret();
+            
+            if (empty($secret) && Api::getToken() !== null)
+            {
+                throw new Errors\SignatureVerificationError(
+                    'When using OAuth authentication, you must explicitly provide the secret for webhook signature verification.');
+            }
+        }
+        
         self::verifySignature($payload, $actualSignature, $secret);
     }
 
     public function verifySignature($payload, $actualSignature, $secret)
     {
+        if (empty($secret))
+        {
+            throw new Errors\SignatureVerificationError(
+                'No secret available for signature verification. Make sure to provide it or initialize Api with a secret key.');
+        }
+
         $expectedSignature = hash_hmac(self::SHA256, $payload, $secret);
 
         // Use lang's built-in hash_equals if exists to mitigate timing attacks
@@ -90,7 +122,7 @@ private function encrypt($dataToEncrypt, $secret) {
             $encryptedData = openssl_encrypt($dataToEncrypt, $cipher, $key, OPENSSL_RAW_DATA, $iv, $tag, '', 16);
     
             if ($encryptedData === false) {
-                throw new Exception('Encryption failed');
+                throw new \Exception('Encryption failed');
             }
     
             // Concatenate encrypted data with the authentication tag
@@ -98,8 +130,8 @@ private function encrypt($dataToEncrypt, $secret) {
     
             // Convert to hex string
             return bin2hex($finalData);
-        } catch (Exception $e) {
-            throw new Exception('Encryption failed: ' . $e->getMessage());
+        } catch (\Exception $e) {
+            throw new \Exception('Encryption failed: ' . $e->getMessage());
         }
     }
 
diff --git a/tests/SignatureVerificationTest.php b/tests/SignatureVerificationTest.php
index 1037676..e0ad223 100644
--- a/tests/SignatureVerificationTest.php
+++ b/tests/SignatureVerificationTest.php
@@ -3,9 +3,12 @@
 namespace Razorpay\Tests;
 
 use Razorpay\Api\Request;
+use Razorpay\Api\Api;
+use Razorpay\Api\Utility;
 
 class SignatureVerificationTest extends TestCase
 {
+    protected $api;
     private static $subscriptionId;
 
     public function setUp(): void
@@ -64,4 +67,49 @@ public function testSubscriptionVerification()
           'razorpay_signature' => $signature
         )));
     }
+    
+    /**
+     * Test verification with OAuth token authentication
+     */
+    public function testOAuthTokenVerification()
+    {
+        $orderId = 'order_123456789';
+        $paymentId = 'pay_123456789';
+        $secret = 'test_secret_key';
+        
+        // The payload that would be used for signature verification
+        $payload = $orderId . '|' . $paymentId;
+        
+        // Generate a valid signature using the test secret
+        $expectedSignature = hash_hmac('sha256', $payload, $secret);
+        
+        // Create a new API instance with OAuth token
+        $apiWithOAuth = new Api(null, null, 'test_oauth_token');
+        
+        // This should work now with the secret passed in attributes
+        $this->assertNull($apiWithOAuth->utility->verifyPaymentSignature([
+            'razorpay_order_id' => $orderId,
+            'razorpay_payment_id' => $paymentId,
+            'razorpay_signature' => $expectedSignature,
+            'secret' => $secret
+        ]));
+    }
+    
+    /**
+     * Test webhook verification with OAuth token authentication
+     */
+    public function testOAuthTokenWebhookVerification()
+    {
+        $payload = '{"payment_id":"pay_123456789","order_id":"order_123456789"}';
+        $secret = 'webhook_secret_key';
+        
+        // Generate a valid signature using the test secret
+        $expectedSignature = hash_hmac('sha256', $payload, $secret);
+        
+        // Create a new API instance with OAuth token
+        $apiWithOAuth = new Api(null, null, 'test_oauth_token');
+        
+        // Verify webhook signature with explicit secret
+        $this->assertNull($apiWithOAuth->utility->verifyWebhookSignature($payload, $expectedSignature, $secret));
+    }
 }
\ No newline at end of file