diff --git a/src/mem/secure.c b/src/mem/secure.c
new file mode 100644
index 0000000..6cf64d9
--- /dev/null
+++ b/src/mem/secure.c
@@ -0,0 +1,37 @@
+/**
+ * @file mem/secure.c  Secure memory functions
+ *
+ * Copyright (C) 2010 Creytiv.com
+ */
+
+#include <re_types.h>
+#include <re_mem.h>
+
+
+/**
+ * Compare two byte strings in constant time. This function can be used
+ * by secure code to compare secret data, such as authentication tags,
+ * to avoid side-channel attacks.
+ *
+ * @param s1 First byte string
+ * @param s2 Second byte string
+ * @param n  Number of bytes
+ *
+ * @return a negative number if argument errors
+ *         0 if both byte strings matching
+ *         a positive number if not matching
+ */
+int mem_seccmp(const volatile uint8_t *volatile s1,
+	       const volatile uint8_t *volatile s2,
+	       size_t n)
+{
+	uint8_t val = 0;
+
+	if (!s1 || !s2)
+		return -1;
+
+	while (n--)
+		val |= *s1++ ^ *s2++;
+
+	return val;
+}