RAPPOR implementation

components/rappor/rappor_pref_names.cc

Index: components/rappor/rappor_pref_names.cc
diff --git a/components/rappor/rappor_pref_names.cc b/components/rappor/rappor_pref_names.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c9373e92069190ed644d05136f69ff6fca270bc6
--- /dev/null
+++ b/components/rappor/rappor_pref_names.cc
@@ -0,0 +1,20 @@
+// Copyright 2014 The Chromium 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 "components/rappor/rappor_pref_names.h"
+
+namespace rappor {
+namespace prefs {
+
+// A base-64 encoded, randomly generated byte string, which is used as a seed
+// for redacting collected data.

[Ilya Sherman, 2014/02/13 01:39:03]

IMPORTANT: Historically with UMA, we have been very cautious not to store
anything that looks like a unique identifier on the local client, even if it is
never transmitted via the network.  Is this client secret equivalent to a unique
identifier?  If so, we should have a deep privacy discussion about this.

Regardless of your answer above, please document the expected entropy of this
client secret -- i.e., how many random bytes are in the string?

[Steven Holte, 2014/02/13 05:11:12]

Well this has at least 192 bits of entropy, should probably have double that,
and is randomly generated on the client, so it would definitely be unique.  Not
sure I understand the rational about not wanting to store such a value though. 
At that amount of entropy, documenting the amount of entropy seems a bit moot
for your purposes.

[Ilya Sherman, 2014/02/13 23:23:08]

Started an email thread to discuss this.

+// Important: This value should remain secret at the client, and never be
+// reported on the network, or to the server.
+const char kRapporSecret[] = "rappor.secret";
+
+// A randomly generated number, which determines cohort data is reported for.

[Ilya Sherman, 2014/02/13 01:39:03]

Essentially the same comment as above applies here.

+const char kRapporCohort[] = "rappor.cohort";
+
+}  // namespace prefs
+}  // namespace rappor