diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index bb600d403..9456e06a5 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -38,6 +38,7 @@ set(src
      timing.c
      version.c
      x509parse.c
+     x509write.c
      xtea.c
 )