diff --git a/src/Storage/StorageObject.php b/src/Storage/StorageObject.php
index c747954bc27f..b1cbb7f05bc3 100644
--- a/src/Storage/StorageObject.php
+++ b/src/Storage/StorageObject.php
@@ -786,10 +786,12 @@ public function signedUrl($expires, array $options = [])
             $options['contentMd5'],
             $options['contentType'],
             $seconds,
-            implode(PHP_EOL, $headers) . $resource,
+            implode("\n", $headers) . $resource,
         ];
 
-        $string = implode(PHP_EOL, $toSign);
+        // NOTE: While in most cases `PHP_EOL` is preferable to a system-specific character,
+        // in this case `\n` is required.
+        $string = implode("\n", $toSign);
         $signature = $this->signString($keyFile['private_key'], $string, $options['forceOpenssl']);
         $encodedSignature = urlencode(base64_encode($signature));
 
diff --git a/tests/unit/Storage/StorageObjectTest.php b/tests/unit/Storage/StorageObjectTest.php
index 89b697e22b6f..40315eea7d6b 100644
--- a/tests/unit/Storage/StorageObjectTest.php
+++ b/tests/unit/Storage/StorageObjectTest.php
@@ -554,7 +554,7 @@ public function testSignedUrl()
             'contentMd5' => $digest
         ]);
 
-        $input = implode(PHP_EOL, [
+        $input = implode("\n", [
             'GET',
             $digest,
             $contentType,
@@ -589,7 +589,7 @@ public function testSignedUrlWithSaveAsName()
             'saveAsName' => 'foo'
         ]);
 
-        $input = implode(PHP_EOL, [
+        $input = implode("\n", [
             'GET',
             '',
             '',
@@ -622,7 +622,7 @@ public function testSignedUrlConnectionKeyfile()
 
         $url = $object->signedUrl($ts);
 
-        $input = implode(PHP_EOL, [
+        $input = implode("\n", [
             'GET',
             '',
             '',
@@ -661,7 +661,7 @@ public function testSignedUrlWithSpace()
             'contentMd5' => $digest
         ]);
 
-        $input = implode(PHP_EOL, [
+        $input = implode("\n", [
             'GET',
             $digest,
             $contentType,
@@ -711,7 +711,7 @@ public function testSignedUploadUrl()
             'contentMd5' => $digest
         ]);
 
-        $input = implode(PHP_EOL, [
+        $input = implode("\n", [
             'POST',
             $digest,
             $contentType,