diff --git a/plume-common/src/activity_pub/mod.rs b/plume-common/src/activity_pub/mod.rs
index dd739634..539af143 100644
--- a/plume-common/src/activity_pub/mod.rs
+++ b/plume-common/src/activity_pub/mod.rs
@@ -164,7 +164,7 @@ where
                 .headers(headers.clone())
                 .header(
                     "Signature",
-                    request::signature(sender, &headers, "post", url.path(), url.query())
+                    request::signature(sender, &headers, ("post", url.path(), url.query()))
                         .expect("activity_pub::broadcast: request signature error"),
                 )
                 .body(body)
diff --git a/plume-common/src/activity_pub/request.rs b/plume-common/src/activity_pub/request.rs
index 4ffe7754..6768f2b0 100644
--- a/plume-common/src/activity_pub/request.rs
+++ b/plume-common/src/activity_pub/request.rs
@@ -115,14 +115,14 @@ pub fn headers() -> HeaderMap {
 type Method<'a> = &'a str;
 type Path<'a> = &'a str;
 type Query<'a> = &'a str;
+type RequestTarget<'a> = (Method<'a>, Path<'a>, Option<Query<'a>>);
 
 pub fn signature<S: Signer>(
     signer: &S,
     headers: &HeaderMap,
-    method: Method,
-    path: Path,
-    query: Option<Query>,
+    request_target: RequestTarget,
 ) -> Result<HeaderValue, Error> {
+    let (method, path, query) = request_target;
     let origin_form = if let Some(query) = query {
         format!("{}?{}", path, query)
     } else {