diff --git a/src/base/abci/abcDar.c b/src/base/abci/abcDar.c
index c2a253830..eed4db4f7 100644
--- a/src/base/abci/abcDar.c
+++ b/src/base/abci/abcDar.c
@@ -3018,7 +3018,7 @@ int Abc_NtkDarSec( Abc_Ntk_t * pNtk1, Abc_Ntk_t * pNtk2, Fra_Sec_t * pSecPar )
     // perform verification
     RetValue = Fra_FraigSec( pMan, pSecPar, NULL );
     Aig_ManStop( pMan );
-    return RetValue;
+    return RetValue == -1 ? -1 : !RetValue;
 }
 
 /**Function*************************************************************