diff --git a/library/timing.c b/library/timing.c
index 47e34f9..cd74129 100644
--- a/library/timing.c
+++ b/library/timing.c
@@ -17,6 +17,8 @@
  *  limitations under the License.
  */
 
+#include <string.h>
+
 #include "common.h"
 
 #include "mbedtls/platform.h"
@@ -231,7 +233,10 @@
 
 unsigned long mbedtls_timing_get_timer(struct mbedtls_timing_hr_time *val, int reset)
 {
-    struct _hr_time *t = (struct _hr_time *) val;
+    /* Copy val to an 8-byte-aligned address, so that we can safely cast it */
+    uint64_t val_aligned[(sizeof(struct mbedtls_timing_hr_time) + 7) / 8];
+    memcpy(val_aligned, val, sizeof(struct _hr_time));
+    struct _hr_time *t = (struct _hr_time *)val_aligned;
 
     if (reset) {
         QueryPerformanceCounter(&t->start);
@@ -277,7 +282,10 @@
 
 unsigned long mbedtls_timing_get_timer(struct mbedtls_timing_hr_time *val, int reset)
 {
-    struct _hr_time *t = (struct _hr_time *) val;
+    /* Copy val to an 8-byte-aligned address, so that we can safely cast it */
+    uint64_t val_aligned[(sizeof(struct mbedtls_timing_hr_time) + 7) / 8];
+    memcpy(val_aligned, val, sizeof(struct _hr_time));
+    struct _hr_time *t = (struct _hr_time *)val_aligned;
 
     if (reset) {
         gettimeofday(&t->start, NULL);