diff --git a/includes/class-signature.php b/includes/class-signature.php
index f0ca349..0b2184d 100644
--- a/includes/class-signature.php
+++ b/includes/class-signature.php
@@ -112,12 +112,14 @@ class Signature {
 
 	public static function verify_http_signature( $request ) {
 		$headers = $request->get_headers();
-		$actor = isset( json_decode( $request->get_body() )->actor ) ? json_decode( $request->get_body() )->actor : '';
-		$headers['(request-target)'][0] = strtolower( $request->get_method() ) . ' /wp-json' . $request->get_route();
 
 		if ( ! $headers ) {
-			$headers = self::default_server_headers();
+			return false;
 		}
+
+		$actor = isset( json_decode( $request->get_body() )->actor ) ? json_decode( $request->get_body() )->actor : '';
+		$headers['(request-target)'][0] = strtolower( $request->get_method() ) . ' /' . rest_get_url_prefix() . $request->get_route();
+
 		if ( array_key_exists( 'signature', $headers ) ) {
 			$signature_block = self::parse_signature_header( $headers['signature'] );
 		} elseif ( array_key_exists( 'authorization', $headers ) ) {