diff --git a/app/Util/ActivityPub/HttpSignature.php b/app/Util/ActivityPub/HttpSignature.php
index 35facb82b..e6834aaef 100644
--- a/app/Util/ActivityPub/HttpSignature.php
+++ b/app/Util/ActivityPub/HttpSignature.php
@@ -25,7 +25,13 @@ class HttpSignature
         $stringToSign = self::_headersToSigningString($headers);
         $signedHeaders = implode(' ', array_map('strtolower', array_keys($headers)));
         $key = openssl_pkey_get_private($user->private_key);
+        if (empty($key)) {
+            return [];
+        }
         openssl_sign($stringToSign, $signature, $key, OPENSSL_ALGO_SHA256);
+        if (empty($signature)) {
+            return [];
+        }
         $signature = base64_encode($signature);
         $signatureHeader = 'keyId="'.$user->keyId().'",headers="'.$signedHeaders.'",algorithm="rsa-sha256",signature="'.$signature.'"';
         unset($headers['(request-target)']);
@@ -34,6 +40,34 @@ class HttpSignature
         return self::_headersToCurlArray($headers);
     }
 
+    public static function signRaw($privateKey, $keyId, $url, $body = false, $addlHeaders = [])
+    {
+        if (empty($privateKey) || empty($keyId)) {
+            return [];
+        }
+        if ($body) {
+            $digest = self::_digest($body);
+        }
+        $headers = self::_headersToSign($url, $body ? $digest : false);
+        $headers = array_merge($headers, $addlHeaders);
+        $stringToSign = self::_headersToSigningString($headers);
+        $signedHeaders = implode(' ', array_map('strtolower', array_keys($headers)));
+        $key = openssl_pkey_get_private($privateKey);
+        if (empty($key)) {
+            return [];
+        }
+        openssl_sign($stringToSign, $signature, $key, OPENSSL_ALGO_SHA256);
+        if (empty($signature)) {
+            return [];
+        }
+        $signature = base64_encode($signature);
+        $signatureHeader = 'keyId="'.$keyId.'",headers="'.$signedHeaders.'",algorithm="rsa-sha256",signature="'.$signature.'"';
+        unset($headers['(request-target)']);
+        $headers['Signature'] = $signatureHeader;
+
+        return self::_headersToCurlArray($headers);
+    }
+
     public static function instanceActorSign($url, $body = false, $addlHeaders = [], $method = 'post')
     {
         $keyId = config('app.url').'/i/actor#main-key';