Initial patch from Will.

src/platform/cryptohome/secure_blob.cc

+// 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.
+
+#include "cryptohome/secure_blob.h"
+
+namespace cryptohome {
+
+SecureBlob::SecureBlob()
+    : chromeos::Blob() {
+}
+
+SecureBlob::SecureBlob(chromeos::Blob::const_iterator begin,
+                       chromeos::Blob::const_iterator end)
+    : chromeos::Blob(begin, end) {
+}
+
+SecureBlob::SecureBlob(int size)
+    : chromeos::Blob(size) {
+}
+
+SecureBlob::~SecureBlob() {
+  chromeos::SecureMemset(&this->front(), this->capacity(), 0);
+}
+
+void SecureBlob::resize(size_type sz) {
+  if(sz < size()) {
+    chromeos::SecureMemset(&this->at(sz), size() - sz, 0);
+  }
+  chromeos::Blob::resize(sz);
+}
+
+void SecureBlob::resize(size_type sz, const SecureBlobElement& x) {
+  if(sz < size()) {
+    chromeos::SecureMemset(&this->at(sz), size() - sz, 0);
+  }
+  chromeos::Blob::resize(sz, x);
+}
+
+}  // cryptohome