Initial patch from Will.

src/platform/cryptohome/secure_blob.h

Index: src/platform/cryptohome/secure_blob.h
diff --git a/src/platform/cryptohome/secure_blob.h b/src/platform/cryptohome/secure_blob.h
new file mode 100644
index 0000000000000000000000000000000000000000..aa5afd1ac8582adaa2581e48a1e72cf67bb16c55
--- /dev/null
+++ b/src/platform/cryptohome/secure_blob.h
@@ -0,0 +1,30 @@
+// Copyright (c) 2009-2010 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SECURE_BLOB_H_
+#define SECURE_BLOB_H_
+
+#include "chromeos/utility.h"
+
+namespace cryptohome {
+
+typedef unsigned char SecureBlobElement;
+
+// SecureBlob erases the contents on destruction.  It does not guarantee erasure
+// on resize, assign, etc.
+class SecureBlob : public chromeos::Blob {
+ public:
+  SecureBlob();
+  SecureBlob(chromeos::Blob::const_iterator begin,
+             chromeos::Blob::const_iterator end);
+  explicit SecureBlob(int size);
+  virtual ~SecureBlob();
+
+  void resize(size_type sz);
+  void resize(size_type sz, const SecureBlobElement& x);
+};
+
+}  // cryptohome
+
+#endif  // SECURE_BLOB_H_