diff --git a/crypto/test/test_util.cc b/crypto/test/test_util.cc
new file mode 100644
index 0000000..8021aaa
--- /dev/null
+++ b/crypto/test/test_util.cc
@@ -0,0 +1,30 @@
+/* Copyright (c) 2015, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <stdint.h>
+#include <stdio.h>
+
+#include "test_util.h"
+
+
+void hexdump(FILE *fp, const char *msg, const void *in, size_t len) {
+  const uint8_t *data = reinterpret_cast<const uint8_t*>(in);
+  size_t i;
+
+  fputs(msg, fp);
+  for (i = 0; i < len; i++) {
+    fprintf(fp, "%02x", data[i]);
+  }
+  fputs("\n", fp);
+}