diff --git a/Include/Python.h b/Include/Python.h
--- a/Include/Python.h
+++ b/Include/Python.h
@@ -123,6 +123,7 @@
 #include "eval.h"
 
 #include "pyctype.h"
+#include "pymemsets.h"
 #include "pystrtod.h"
 #include "pystrcmp.h"
 #include "dtoa.h"
diff --git a/Makefile.pre.in b/Makefile.pre.in
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -350,6 +350,7 @@
 		Python/importdl.o \
 		Python/marshal.o \
 		Python/modsupport.o \
+		Python/mymemsets.o \
 		Python/mystrtoul.o \
 		Python/mysnprintf.o \
 		Python/peephole.o \
@@ -819,6 +820,7 @@
 		$(srcdir)/Include/pyerrors.h \
 		$(srcdir)/Include/pyfpe.h \
 		$(srcdir)/Include/pymath.h \
+		$(srcdir)/Include/pymemsets.h \
 		$(srcdir)/Include/pygetopt.h \
 		$(srcdir)/Include/pymacro.h \
 		$(srcdir)/Include/pymem.h \
diff --git a/Modules/_sha3/sha3module.c b/Modules/_sha3/sha3module.c
--- a/Modules/_sha3/sha3module.c
+++ b/Modules/_sha3/sha3module.c
@@ -150,7 +150,8 @@
 #define SHA3_process Update
 #define SHA3_done Final
 #define SHA3_copystate(dest, src) memcpy(&(dest), &(src), sizeof(SHA3_state))
-#define SHA3_clearstate(state) memset(&(state), 0, sizeof(SHA3_state))
+#define SHA3_clearstate(state) _Py_memset_s(&(state), sizeof(SHA3_state),\
+                                            0, sizeof(SHA3_state))
 
 /* The structure for storing SHA3 info */
 
diff --git a/Modules/sha1module.c b/Modules/sha1module.c
--- a/Modules/sha1module.c
+++ b/Modules/sha1module.c
@@ -301,9 +301,11 @@
 /* Internal methods for a hash object */
 
 static void
-SHA1_dealloc(PyObject *ptr)
+SHA1_dealloc(SHA1object *self)
 {
-    PyObject_Del(ptr);
+     _Py_memset_s(&(self->hash_state), sizeof(struct sha1_state),
+                  0, sizeof(struct sha1_state));
+    PyObject_Del(self);
 }
 
 
@@ -443,7 +445,7 @@
     sizeof(SHA1object), /*tp_size*/
     0,                  /*tp_itemsize*/
     /* methods */
-    SHA1_dealloc,       /*tp_dealloc*/
+    (destructor)SHA1_dealloc,       /*tp_dealloc*/
     0,                  /*tp_print*/
     0,                  /*tp_getattr*/
     0,                  /*tp_setattr*/
diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -425,6 +425,7 @@
     <ClInclude Include="..\Include\pytime.h" />
     <ClInclude Include="..\Include\pymacro.h" />
     <ClInclude Include="..\Include\pymem.h" />
+    <ClInclude Include="..\Include\pymemsets.h" />
     <ClInclude Include="..\Include\pyport.h" />
     <ClInclude Include="..\Include\pystate.h" />
     <ClInclude Include="..\Include\pystrcmp.h" />
@@ -638,6 +639,7 @@
     <ClCompile Include="..\Python\importdl.c" />
     <ClCompile Include="..\Python\marshal.c" />
     <ClCompile Include="..\Python\modsupport.c" />
+    <ClCompile Include="..\Python\mymemsets.c" />
     <ClCompile Include="..\Python\mysnprintf.c" />
     <ClCompile Include="..\Python\mystrtoul.c" />
     <ClCompile Include="..\Python\peephole.c" />
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -97,6 +97,9 @@
 extern void _PyGILState_Fini(void);
 #endif /* WITH_THREAD */
 
+/* Hack to force loading of mymemset.o */
+errno_t (*_Py_memset_s_hack)(void*, rsize_t, int, rsize_t) = _Py_memset_s;
+
 int Py_DebugFlag; /* Needed by parser.c */
 int Py_VerboseFlag; /* Needed by import.c */
 int Py_QuietFlag; /* Needed by sysmodule.c */
diff --git a/configure b/configure
--- a/configure
+++ b/configure
@@ -10459,6 +10459,32 @@
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for memset_s" >&5
+$as_echo_n "checking for memset_s... " >&6; }
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <string.h>
+int
+main ()
+{
+char buf[10]; memset_s(buf, sizeof(buf), 0, sizeof(buf));
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+
+$as_echo "#define HAVE_MEMSET_S 1" >>confdefs.h
+
+   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for epoll" >&5
 $as_echo_n "checking for epoll... " >&6; }
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -2872,6 +2872,13 @@
    AC_MSG_RESULT(yes)],
   [AC_MSG_RESULT(no)
 ])
+AC_MSG_CHECKING(for memset_s)
+AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <string.h>]],
+  [[char buf[10]; memset_s(buf, sizeof(buf), 0, sizeof(buf))]])],
+  [AC_DEFINE(HAVE_MEMSET_S, 1, Define if you have the C11 'memset_s' function.)
+   AC_MSG_RESULT(yes)],
+  [AC_MSG_RESULT(no)
+])
 AC_MSG_CHECKING(for epoll)
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/epoll.h>]], [[void *x=epoll_create]])],
   [AC_DEFINE(HAVE_EPOLL, 1, Define if you have the 'epoll' functions.)
diff --git a/pyconfig.h.in b/pyconfig.h.in
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -549,6 +549,9 @@
 /* Define to 1 if you have the `memrchr' function. */
 #undef HAVE_MEMRCHR
 
+/* Define if you have the C11 'memset_s' function. */
+#undef HAVE_MEMSET_S
+
 /* Define to 1 if you have the `mkdirat' function. */
 #undef HAVE_MKDIRAT