diff --git a/CMakeLists.txt b/CMakeLists.txt
index 86ec204..92e48f1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -192,6 +192,7 @@ if(LIBVNCSERVER_WITH_WEBSOCKETS)
     ${LIBVNCSERVER_DIR}/websockets.c
     ${LIBVNCSERVER_DIR}/${WSSRCS}
     ${COMMON_DIR}/md5.c
+    ${COMMON_DIR}/sha1.c
   )
 endif(LIBVNCSERVER_WITH_WEBSOCKETS)