RAPPOR implementation

components/rappor/proto/rappor_metric.proto

+// 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.
+//
+// Contains information collected by the RAPPOR (Randomized Aggregatable
+// Privacy-Preserving Ordinal Responses) system.
+//
+// For a full description of the rappor metrics, see
+// http://www.chromium.org/developers/design-documents/rappor
+
+syntax = "proto2";
+
+option optimize_for = LITE_RUNTIME;
+
+package rappor;
+
+message RapporReports {

[ulfar, 2014/02/07 20:19:02]

What about version numbers?  We could piggy-back version numbers on cohort
numbers later, but building in support seems good as well.

[Steven Holte, 2014/02/07 21:08:16]

Done.

+  message Report {
+    // The name of the metric, hashed.
+    optional fixed64 name_hash = 1;
+
+    // The sequence of bits produced by random coin flips in
+    // RapporMetric::GetReport().  For a complete description of RAPPOR
+    // metrics, refer to the design document at:
+    // http://www.chromium.org/developers/design-documents/rappor
+    optional bytes bits = 2;
+  }
+  repeated Report report = 1;
+
+  // Which cohort this report belongs to, which varies the hash functions
+  // used in the bloom filter.

[ulfar, 2014/02/07 20:19:02]

Better comment:

// Which cohort this report belongs to.  The RAPPOR participants are partitioned
into cohorts
// in different ways, to allow better statistics and increased coverage.  In
particular, the cohort
// will serve to choose the hash functions used for Bloom-filter-based reports.

[Steven Holte, 2014/02/07 21:08:16]

Done.

+  optional int32 cohort = 2;
+}