diff --git a/Android.bp b/Android.bp
index ece4ad0..4fe80b2 100644
--- a/Android.bp
+++ b/Android.bp
@@ -12462,7 +12462,9 @@
     name: "perfetto_src_trace_redaction_trace_redaction",
     srcs: [
         "src/trace_redaction/find_package_uid.cc",
+        "src/trace_redaction/populate_allow_lists.cc",
         "src/trace_redaction/prune_package_list.cc",
+        "src/trace_redaction/scrub_trace_packet.cc",
         "src/trace_redaction/trace_redaction_framework.cc",
         "src/trace_redaction/trace_redactor.cc",
     ],
@@ -12474,6 +12476,7 @@
     srcs: [
         "src/trace_redaction/find_package_uid_unittest.cc",
         "src/trace_redaction/prune_package_list_unittest.cc",
+        "src/trace_redaction/scrub_trace_packet_unittest.cc",
     ],
 }
 
diff --git a/src/trace_redaction/BUILD.gn b/src/trace_redaction/BUILD.gn
index 4536331..cff9588 100644
--- a/src/trace_redaction/BUILD.gn
+++ b/src/trace_redaction/BUILD.gn
@@ -18,8 +18,12 @@
   sources = [
     "find_package_uid.cc",
     "find_package_uid.h",
+    "populate_allow_lists.cc",
+    "populate_allow_lists.h",
     "prune_package_list.cc",
     "prune_package_list.h",
+    "scrub_trace_packet.cc",
+    "scrub_trace_packet.h",
     "trace_redaction_framework.cc",
     "trace_redaction_framework.h",
     "trace_redactor.cc",
@@ -58,12 +62,14 @@
   sources = [
     "find_package_uid_unittest.cc",
     "prune_package_list_unittest.cc",
+    "scrub_trace_packet_unittest.cc",
   ]
   deps = [
     ":trace_redaction",
     "../../gn:default_deps",
     "../../gn:gtest_and_gmock",
     "../../protos/perfetto/trace:non_minimal_cpp",
+    "../../protos/perfetto/trace:zero",
     "../../protos/perfetto/trace/android:cpp",
     "../../protos/perfetto/trace/ps:cpp",
     "../../protos/perfetto/trace/ps:zero",
diff --git a/src/trace_redaction/populate_allow_lists.cc b/src/trace_redaction/populate_allow_lists.cc
new file mode 100644
index 0000000..b14b1f6
--- /dev/null
+++ b/src/trace_redaction/populate_allow_lists.cc
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "src/trace_redaction/populate_allow_lists.h"
+
+#include "perfetto/base/status.h"
+#include "src/trace_redaction/trace_redaction_framework.h"
+
+#include "protos/perfetto/trace/trace_packet.pbzero.h"
+
+namespace perfetto::trace_redaction {
+
+base::Status PopulateAllowlists::Build(Context* context) const {
+  if (!context->trace_packet_allow_list.empty()) {
+    return base::ErrStatus("Trace packet allow-list should be empty.");
+  }
+
+  context->trace_packet_allow_list = {
+      protos::pbzero::TracePacket::kProcessTreeFieldNumber,
+      protos::pbzero::TracePacket::kProcessStatsFieldNumber,
+      protos::pbzero::TracePacket::kClockSnapshotFieldNumber,
+      protos::pbzero::TracePacket::kSysStatsFieldNumber,
+      protos::pbzero::TracePacket::kTraceConfigFieldNumber,
+      protos::pbzero::TracePacket::kTraceStatsFieldNumber,
+      protos::pbzero::TracePacket::kSystemInfoFieldNumber,
+      protos::pbzero::TracePacket::kTriggerFieldNumber,
+      protos::pbzero::TracePacket::kCpuInfoFieldNumber,
+      protos::pbzero::TracePacket::kServiceEventFieldNumber,
+      protos::pbzero::TracePacket::kInitialDisplayStateFieldNumber,
+      protos::pbzero::TracePacket::kFrameTimelineEventFieldNumber,
+      protos::pbzero::TracePacket::kAndroidSystemPropertyFieldNumber,
+      protos::pbzero::TracePacket::kSynchronizationMarkerFieldNumber,
+      protos::pbzero::TracePacket::kFtraceEventsFieldNumber,
+  };
+
+  return base::OkStatus();
+}
+
+}  // namespace perfetto::trace_redaction
diff --git a/src/trace_redaction/populate_allow_lists.h b/src/trace_redaction/populate_allow_lists.h
new file mode 100644
index 0000000..5a05d42
--- /dev/null
+++ b/src/trace_redaction/populate_allow_lists.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SRC_TRACE_REDACTION_POPULATE_ALLOW_LISTS_H_
+#define SRC_TRACE_REDACTION_POPULATE_ALLOW_LISTS_H_
+
+#include "perfetto/base/status.h"
+#include "src/trace_redaction/trace_redaction_framework.h"
+
+namespace perfetto::trace_redaction {
+
+// Populates the different allow-lists needed to remove data from the trace.
+// Configuration data in the context can be used to change the contents of the
+// lists.
+class PopulateAllowlists final : public BuildPrimitive {
+ public:
+  base::Status Build(Context* context) const override;
+};
+
+}  // namespace perfetto::trace_redaction
+
+#endif  // SRC_TRACE_REDACTION_POPULATE_ALLOW_LISTS_H_
diff --git a/src/trace_redaction/scrub_trace_packet.cc b/src/trace_redaction/scrub_trace_packet.cc
new file mode 100644
index 0000000..e4f03cf
--- /dev/null
+++ b/src/trace_redaction/scrub_trace_packet.cc
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "src/trace_redaction/scrub_trace_packet.h"
+
+namespace perfetto::trace_redaction {
+// The TracePacket message has a simple structure. At its core its one sub
+// message (e.g. ProcessTree) and some additional context (e.g. timestamp).
+// This makes the per-packet check binary - does it contain one of the
+// allow-listed messages?
+//
+// This transform will be called P times where P is the number of packet in the
+// trace.
+//
+// There are A packet types in the allow-list. The allow-list in a set with logA
+// look up. Since the allow-list is relatively small and constant in size,
+// allow-list can be considered constant.
+//
+// There are at most F fields where F is the max number of concurrent fields in
+// a trace packet. Given the limit, this can be considered constant.
+//
+// All together, this implementation can be considered linear in relation to the
+// trace size.
+base::Status ScrubTracePacket::Transform(const Context& context,
+                                         std::string* packet) const {
+  if (packet == nullptr || packet->empty()) {
+    return base::ErrStatus("Cannot scrub null or empty trace packet.");
+  }
+
+  const auto& allow_list = context.trace_packet_allow_list;
+
+  if (allow_list.empty()) {
+    return base::ErrStatus("Cannot scrub trace packets, missing allow-list.");
+  }
+
+  protozero::ProtoDecoder d(*packet);
+
+  // A packet should only have one data type (proto oneof), but there are other
+  // values in the packet (e.g. timestamp). If one field is in the allowlist,
+  // then allow the whole trace packet.
+  for (auto f = d.ReadField(); f.valid(); f = d.ReadField()) {
+    if (allow_list.count(f.id()) != 0) {
+      return base::OkStatus();
+    }
+  }
+
+  packet->clear();
+  return base::OkStatus();
+}
+
+}  // namespace perfetto::trace_redaction
diff --git a/src/trace_redaction/scrub_trace_packet.h b/src/trace_redaction/scrub_trace_packet.h
new file mode 100644
index 0000000..06710d3
--- /dev/null
+++ b/src/trace_redaction/scrub_trace_packet.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SRC_TRACE_REDACTION_SCRUB_TRACE_PACKET_H_
+#define SRC_TRACE_REDACTION_SCRUB_TRACE_PACKET_H_
+
+#include "src/trace_redaction/trace_redaction_framework.h"
+
+#include "protos/perfetto/trace/trace_packet.pbzero.h"
+
+namespace perfetto::trace_redaction {
+
+// Drops whole trace packets based on an allow-list (e.g. retain ProcessTree
+// packets).
+class ScrubTracePacket final : public TransformPrimitive {
+ public:
+  base::Status Transform(const Context& context,
+                         std::string* packet) const override;
+};
+
+}  // namespace perfetto::trace_redaction
+
+#endif  // SRC_TRACE_REDACTION_SCRUB_TRACE_PACKET_H_
diff --git a/src/trace_redaction/scrub_trace_packet_unittest.cc b/src/trace_redaction/scrub_trace_packet_unittest.cc
new file mode 100644
index 0000000..82b99d4
--- /dev/null
+++ b/src/trace_redaction/scrub_trace_packet_unittest.cc
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string>
+
+#include "src/base/test/status_matchers.h"
+#include "src/trace_redaction/scrub_trace_packet.h"
+#include "test/gtest_and_gmock.h"
+
+#include "protos/perfetto/trace/ps/process_tree.gen.h"
+#include "protos/perfetto/trace/trace_packet.pbzero.h"
+
+namespace perfetto::trace_redaction {
+
+TEST(ScrubTracePacketTest, ReturnErrorForNullPacket) {
+  // Have something in the allow-list to avoid that error.
+  Context context;
+  context.trace_packet_allow_list.insert(
+      protos::pbzero::TracePacket::kProcessTreeFieldNumber);
+
+  ScrubTracePacket scrub;
+  ASSERT_FALSE(scrub.Transform(context, nullptr).ok());
+}
+
+TEST(ScrubTracePacketTest, ReturnErrorForEmptyPacket) {
+  // Have something in the allow-list to avoid that error.
+  Context context;
+  context.trace_packet_allow_list.insert(
+      protos::pbzero::TracePacket::kProcessTreeFieldNumber);
+
+  std::string packet_str = "";
+
+  ScrubTracePacket scrub;
+  ASSERT_FALSE(scrub.Transform(context, &packet_str).ok());
+}
+
+TEST(ScrubTracePacketTest, ReturnErrorForEmptyAllowList) {
+  // The context will have no allow-list entries. ScrubTracePacket should fail.
+  Context context;
+
+  protos::gen::TracePacket packet;
+  std::string packet_str = packet.SerializeAsString();
+
+  ScrubTracePacket scrub;
+  ASSERT_FALSE(scrub.Transform(context, &packet_str).ok());
+}
+
+// The whole packet should be dropped (cleared) when it has a data type not
+// included in the allow-list.
+TEST(ScrubTracePacketTest, DropsOutsiderPacketType) {
+  protos::gen::TracePacket packet;
+  packet.set_timestamp(1234);
+  packet.mutable_android_camera_frame_event();  // Creates and sets data.
+
+  std::string packet_str = packet.SerializeAsString();
+  ASSERT_GT(packet_str.size(), 0u);
+
+  // Populate the allow-list with something that doesn't match the data in the
+  // packet.
+  Context context;
+  context.trace_packet_allow_list.insert(
+      protos::pbzero::TracePacket::kProcessTreeFieldNumber);
+
+  ScrubTracePacket scrub;
+  ASSERT_OK(scrub.Transform(context, &packet_str));
+
+  ASSERT_TRUE(packet_str.empty());
+}
+
+// Typically a trace packet should always have a data type (e.g. ProcessTree),
+// but it is possible that another transformation has cleared that data. If
+// that's the case, this primitive should treat it as an outsider.
+TEST(ScrubTracePacketTest, DropsPacketsWithNoType) {
+  protos::gen::TracePacket packet;
+  packet.set_timestamp(1234);
+
+  std::string packet_str = packet.SerializeAsString();
+  ASSERT_GT(packet_str.size(), 0u);
+
+  Context context;
+  context.trace_packet_allow_list.insert(
+      protos::pbzero::TracePacket::kProcessTreeFieldNumber);
+
+  ScrubTracePacket scrub;
+  ASSERT_OK(scrub.Transform(context, &packet_str));
+
+  ASSERT_TRUE(packet_str.empty());
+}
+
+// A packet should not change (at all) if it's in the allow-list.
+TEST(ScrubTracePacketTest, SkipsAllowedPacket) {
+  protos::gen::TracePacket packet;
+  packet.set_timestamp(1234);
+
+  // Add a process tree to the packet. Process trees are in the allow-list.
+  auto* process = packet.mutable_process_tree()->add_processes();
+  process->set_uid(0);
+  process->set_ppid(3);
+  process->set_pid(7);
+
+  std::string original_packet_str = packet.SerializeAsString();
+  ASSERT_GT(original_packet_str.size(), 0u);
+
+  // Make a copy that can be modified by the primitive (even though it shouldn't
+  // be).
+  std::string mutable_packet_str(original_packet_str);
+
+  Context context;
+  context.trace_packet_allow_list.insert(
+      protos::pbzero::TracePacket::kProcessTreeFieldNumber);
+
+  ScrubTracePacket scrub;
+  ASSERT_OK(scrub.Transform(context, &mutable_packet_str));
+
+  // The transform shouldn't have changed the string, so the string before and
+  // after should match.
+  ASSERT_EQ(original_packet_str, mutable_packet_str);
+}
+
+}  // namespace perfetto::trace_redaction
diff --git a/src/trace_redaction/trace_redaction_framework.h b/src/trace_redaction/trace_redaction_framework.h
index c9e7fb4..b481961 100644
--- a/src/trace_redaction/trace_redaction_framework.h
+++ b/src/trace_redaction/trace_redaction_framework.h
@@ -17,10 +17,14 @@
 #ifndef SRC_TRACE_REDACTION_TRACE_REDACTION_FRAMEWORK_H_
 #define SRC_TRACE_REDACTION_TRACE_REDACTION_FRAMEWORK_H_
 
+#include <cstdint>
+#include <optional>
 #include <string>
 #include <vector>
 
+#include "perfetto/base/flat_set.h"
 #include "perfetto/ext/base/status_or.h"
+
 #include "protos/perfetto/trace/trace_packet.gen.h"
 #include "protos/perfetto/trace/trace_packet.pbzero.h"
 
@@ -89,6 +93,31 @@
   //      uid: 1010113
   //    }
   std::optional<uint64_t> package_uid;
+
+  // Trace packets contain a "one of" entry called "data". This field can be
+  // thought of as the message. A track packet with have other fields along
+  // side "data" (e.g. "timestamp"). These fields can be thought of as metadata.
+  //
+  // A message should be removed if:
+  //
+  //  ...we know it contains too much sensitive information
+  //
+  //  ...we know it contains sensitive information and we know how to remove
+  //        the sensitive information, but don't have the resources to do it
+  //        right now
+  //
+  //  ...we know it provide little value
+  //
+  // "trace_packet_allow_list" contains the field ids of trace packets we want
+  // to pass onto later transformations. Examples are:
+  //
+  //    - protos::pbzero::TracePacket::kProcessTreeFieldNumber
+  //    - protos::pbzero::TracePacket::kProcessStatsFieldNumber
+  //    - protos::pbzero::TracePacket::kClockSnapshotFieldNumber
+  //
+  // Because "data" is a "one of", if no field in "trace_packet_allow_list" can
+  // be found, it packet should be removed.
+  base::FlatSet<uint32_t> trace_packet_allow_list;
 };
 
 // Responsible for extracting low-level data from the trace and storing it in
diff --git a/src/trace_redaction/trace_redactor.cc b/src/trace_redaction/trace_redactor.cc
index eb20c27..122d2d9 100644
--- a/src/trace_redaction/trace_redactor.cc
+++ b/src/trace_redaction/trace_redactor.cc
@@ -187,12 +187,25 @@
     auto packet = packet_it->as_std_string();
 
     for (const auto& transformer : transformers_) {
+      // If the packet has been cleared, it means a tranformation has removed it
+      // from the trace. Stop processing it. This saves transforms from having
+      // to check and handle empty packets.
+      if (packet.empty()) {
+        break;
+      }
+
       if (auto status = transformer->Transform(context, &packet);
           !status.ok()) {
         return status;
       }
     }
 
+    // The packet has been removed from the trace. Don't write an empty packet
+    // to disk.
+    if (packet.empty()) {
+      continue;
+    }
+
     protozero::HeapBuffered<> serializer;
     auto* packet_message =
         serializer->BeginNestedMessage<TracePacket>(Trace::kPacketFieldNumber);