1 files changed, 13 insertions, 0 deletions
diff --git a/include/util.h b/include/util.h
index 10d9b3661d..a6de67e3d8 100644
--- a/include/util.h
+++ b/include/util.h
@@ -13,6 +13,7 @@
 #include "panic.h"
 
 #include "builtin/assert.h"         /* For ASSERT(). */
+#include <stdbool.h>
 #include <stddef.h>
 
 #ifdef __cplusplus
@@ -163,6 +164,18 @@ int uint64divmod(uint64_t *v, int by);
 int get_next_bit(uint32_t *mask);
 
 /**
+ * Check if |buffer| is full of 0x00 or 0xff.
+ *
+ * This function runs in constant execution time and is not vulnerable to
+ * timing attacks.
+ *
+ * @param buffer the buffer to check.
+ * @param size the number of bytes to check.
+ * @return true if |buffer| is full of 0x00 or 0xff, false otherwise.
+ */
+bool bytes_are_trivial(const uint8_t *buffer, size_t size);
+
+/**
  * Reverse's the byte-order of the provided buffer.
  */
 void reverse(void *dest, size_t len);