diff --git a/lib/Controller/WopiController.php b/lib/Controller/WopiController.php
index 1c900cca58..fdbe14ff09 100644
--- a/lib/Controller/WopiController.php
+++ b/lib/Controller/WopiController.php
@@ -165,6 +165,11 @@ public function checkFileInfo(string $fileId, string $access_token): JSONRespons
 			$zoteroAPIKey = $this->config->getUserValue($wopi->getEditorUid(), 'richdocuments', 'zoteroAPIKey', '');
 			$response['UserPrivateInfo']['ZoteroAPIKey'] = $zoteroAPIKey;
 		}
+		$enableDocumentSigning = $this->config->getAppValue(Application::APPNAME, 'documentSigningEnabled', 'yes') === 'yes';
+		if (!$isPublic && $enableDocumentSigning) {
+			$documentSigningCa = $this->config->getUserValue($wopi->getEditorUid(), 'richdocuments', 'documentSigningCa', '');
+			$response['UserPrivateInfo']['SignatureCa'] = $documentSigningCa;
+		}
 		if ($wopi->hasTemplateId()) {
 			$response['TemplateSource'] = $this->getWopiUrlForTemplate($wopi);
 		}