diff --git a/src/Symfony/Component/Mime/Crypto/DkimSigner.php b/src/Symfony/Component/Mime/Crypto/DkimSigner.php
index dfb6f226b5e51..f0f7091ed4168 100644
--- a/src/Symfony/Component/Mime/Crypto/DkimSigner.php
+++ b/src/Symfony/Component/Mime/Crypto/DkimSigner.php
@@ -65,7 +65,7 @@ public function sign(Message $message, array $options = []): Message
     {
         $options += $this->defaultOptions;
         if (!\in_array($options['algorithm'], [self::ALGO_SHA256, self::ALGO_ED25519], true)) {
-            throw new InvalidArgumentException('Invalid DKIM signing algorithm "%s".', $options['algorithm']);
+            throw new InvalidArgumentException(sprintf('Invalid DKIM signing algorithm "%s".', $options['algorithm']));
         }
         $headersToIgnore['return-path'] = true;
         $headersToIgnore['x-transport'] = true;
@@ -205,7 +205,7 @@ private function hashBody(AbstractPart $body, string $bodyCanon, int $maxLength)
         }
 
         // Add trailing Line return if last line is non empty
-        if (\strlen($currentLine) > 0) {
+        if ('' !== $currentLine) {
             hash_update($hash, "\r\n");
             $length += \strlen("\r\n");
         }
diff --git a/src/Symfony/Component/Mime/Tests/Crypto/DkimSignerTest.php b/src/Symfony/Component/Mime/Tests/Crypto/DkimSignerTest.php
index e48b0c8e4e3c0..e0eaa54f18757 100644
--- a/src/Symfony/Component/Mime/Tests/Crypto/DkimSignerTest.php
+++ b/src/Symfony/Component/Mime/Tests/Crypto/DkimSignerTest.php
@@ -16,6 +16,7 @@
 use Symfony\Component\Mime\Address;
 use Symfony\Component\Mime\Crypto\DkimSigner;
 use Symfony\Component\Mime\Email;
+use Symfony\Component\Mime\Message;
 
 /**
  * @group time-sensitive
@@ -90,6 +91,21 @@ public function getSignData()
         ];
     }
 
+    public function testSignWithUnsupportedAlgorithm()
+    {
+        $message = $this->createMock(Message::class);
+
+        $signer = new DkimSigner(self::$pk, 'testdkim.symfony.net', 'sf', [
+            'algorithm' => 'unsupported-value',
+        ]);
+
+        $this->expectExceptionObject(
+            new \LogicException('Invalid DKIM signing algorithm "unsupported-value".')
+        );
+
+        $signer->sign($message, []);
+    }
+
     /**
      * @dataProvider getCanonicalizeHeaderData
      */