diff --git a/packager/media/base/key_source.cc b/packager/media/base/key_source.cc
index c4a07eadc5..5ae56209e8 100644
--- a/packager/media/base/key_source.cc
+++ b/packager/media/base/key_source.cc
@@ -14,6 +14,8 @@ namespace {
 const uint8_t kWidevineSystemId[] = {0xed, 0xef, 0x8b, 0xa9, 0x79, 0xd6,
                                      0x4a, 0xce, 0xa3, 0xc8, 0x27, 0xdc,
                                      0xd5, 0x1d, 0x21, 0xed};
+const char kDefaultUUID[] = "";
+const char kDefaultSystemName[] = "";
 }  // namespace
 
 namespace edash_packager {
@@ -67,6 +69,14 @@ Status KeySource::GetCryptoPeriodKey(uint32_t crypto_period_index,
   return Status(error::UNIMPLEMENTED, "");
 }
 
+std::string KeySource::UUID() {
+  return kDefaultUUID;
+}
+
+std::string KeySource::SystemName() {
+  return kDefaultSystemName;
+}
+
 scoped_ptr<KeySource> KeySource::CreateFromHexStrings(
     const std::string& key_id_hex,
     const std::string& key_hex,
diff --git a/packager/media/base/key_source.h b/packager/media/base/key_source.h
index fa3f363d25..4fe5eb4fa0 100644
--- a/packager/media/base/key_source.h
+++ b/packager/media/base/key_source.h
@@ -83,6 +83,19 @@ class KeySource {
                                     TrackType track_type,
                                     EncryptionKey* key);
 
+  /// Returns the UUID of the key source in human readable form.
+  /// UUIDs are listed here:
+  /// http://dashif.org/identifiers/protection/
+  /// @return UUID of the key source, empty string if not specified.
+  virtual std::string UUID();
+
+  /// Returns the name, and possibly with a version number, of the key source.
+  /// (This would be the ContentProtection@value attribute in the MPD. DASH-IF-
+  /// IOP v3.0 recommends this to be the DRM system and version name in human
+  /// readable from.)
+  /// @return the name of the key source, empty string if not specified.
+  virtual std::string SystemName();
+
   /// Create KeySource object from hex strings.
   /// @param key_id_hex is the key id in hex string.
   /// @param key_hex is the key in hex string.
diff --git a/packager/media/base/widevine_key_source.cc b/packager/media/base/widevine_key_source.cc
index f310de713a..e8859277f0 100644
--- a/packager/media/base/widevine_key_source.cc
+++ b/packager/media/base/widevine_key_source.cc
@@ -236,6 +236,10 @@ Status WidevineKeySource::GetCryptoPeriodKey(uint32_t crypto_period_index,
   return GetKeyInternal(crypto_period_index, track_type, key);
 }
 
+std::string WidevineKeySource::UUID() {
+  return "edef8ba9-79d6-4ace-a3c8-27dcd51d21ed";
+}
+
 void WidevineKeySource::set_signer(scoped_ptr<RequestSigner> signer) {
   signer_ = signer.Pass();
 }
diff --git a/packager/media/base/widevine_key_source.h b/packager/media/base/widevine_key_source.h
index 9c91948950..c4fb254133 100644
--- a/packager/media/base/widevine_key_source.h
+++ b/packager/media/base/widevine_key_source.h
@@ -43,6 +43,7 @@ class WidevineKeySource : public KeySource {
   virtual Status GetCryptoPeriodKey(uint32_t crypto_period_index,
                                     TrackType track_type,
                                     EncryptionKey* key) OVERRIDE;
+  virtual std::string UUID() OVERRIDE;
   /// @}
 
   /// Set signer for the key source.
diff --git a/packager/media/event/mpd_notify_muxer_listener.cc b/packager/media/event/mpd_notify_muxer_listener.cc
index aa2ca47456..58ff4fbdac 100644
--- a/packager/media/event/mpd_notify_muxer_listener.cc
+++ b/packager/media/event/mpd_notify_muxer_listener.cc
@@ -19,7 +19,7 @@ namespace edash_packager {
 namespace media {
 
 MpdNotifyMuxerListener::MpdNotifyMuxerListener(MpdNotifier* mpd_notifier)
-    : mpd_notifier_(mpd_notifier), notification_id_(0) {
+    : mpd_notifier_(mpd_notifier), notification_id_(0), is_encrypted_(false) {
   DCHECK(mpd_notifier);
   DCHECK(mpd_notifier->dash_profile() == kOnDemandProfile ||
          mpd_notifier->dash_profile() == kLiveProfile);
@@ -32,12 +32,23 @@ void MpdNotifyMuxerListener::SetContentProtectionSchemeIdUri(
   scheme_id_uri_ = scheme_id_uri;
 }
 
+void MpdNotifyMuxerListener::OnEncryptionInfoReady(
+    const std::string& content_protection_uuid,
+    const std::string& content_protection_name_version,
+    const std::vector<uint8_t>& default_key_id,
+    const std::vector<uint8_t>& pssh) {
+  content_protection_uuid_ = content_protection_uuid;
+  content_protection_name_version_ = content_protection_name_version;
+  default_key_id_.assign(default_key_id.begin(), default_key_id.end());
+  pssh_.assign(pssh.begin(), pssh.end());
+  is_encrypted_ = true;
+}
+
 void MpdNotifyMuxerListener::OnMediaStart(
     const MuxerOptions& muxer_options,
     const StreamInfo& stream_info,
     uint32_t time_scale,
-    ContainerType container_type,
-    bool is_encrypted) {
+    ContainerType container_type) {
   scoped_ptr<MediaInfo> media_info(new MediaInfo());
   if (!internal::GenerateMediaInfo(muxer_options,
                                    stream_info,
@@ -48,7 +59,17 @@ void MpdNotifyMuxerListener::OnMediaStart(
     return;
   }
 
-  if (is_encrypted) {
+  if (is_encrypted_) {
+    internal::SetContentProtectionFields(
+        content_protection_uuid_, content_protection_name_version_,
+        default_key_id_, pssh_, media_info.get());
+  }
+
+  if (is_encrypted_) {
+    // TODO(rkuroiwa): When MediaInfo's content protection fields are processed
+    // in MpdBuilder (e.g. content_protection_uuid, default_key_id) then skip
+    // this step if scheme_id_uri_'s UUID == content_protection_uuid_.
+    // Also consider removing SetContentProtectionSchemeIdUri().
     if (!internal::AddContentProtectionElements(
             container_type, scheme_id_uri_, media_info.get())) {
       LOG(ERROR) << "Failed to add content protection elements.";
diff --git a/packager/media/event/mpd_notify_muxer_listener.h b/packager/media/event/mpd_notify_muxer_listener.h
index 1d8cb119b0..d580881b0b 100644
--- a/packager/media/event/mpd_notify_muxer_listener.h
+++ b/packager/media/event/mpd_notify_muxer_listener.h
@@ -36,11 +36,15 @@ class MpdNotifyMuxerListener : public MuxerListener {
 
   /// @name MuxerListener implementation overrides.
   /// @{
+  virtual void OnEncryptionInfoReady(
+      const std::string& content_protection_uuid,
+      const std::string& content_protection_name_version,
+      const std::vector<uint8_t>& default_key_id,
+      const std::vector<uint8_t>& pssh) OVERRIDE;
   virtual void OnMediaStart(const MuxerOptions& muxer_options,
                             const StreamInfo& stream_info,
                             uint32_t time_scale,
-                            ContainerType container_type,
-                            bool is_encrypted) OVERRIDE;
+                            ContainerType container_type) OVERRIDE;
   virtual void OnSampleDurationReady(uint32_t sample_duration) OVERRIDE;
   virtual void OnMediaEnd(bool has_init_range,
                           uint64_t init_range_start,
@@ -61,6 +65,13 @@ class MpdNotifyMuxerListener : public MuxerListener {
   scoped_ptr<MediaInfo> media_info_;
   std::string scheme_id_uri_;
 
+  bool is_encrypted_;
+  // Storage for values passed to OnEncryptionInfoReady().
+  std::string content_protection_uuid_;
+  std::string content_protection_name_version_;
+  std::string default_key_id_;
+  std::string pssh_;
+
   DISALLOW_COPY_AND_ASSIGN(MpdNotifyMuxerListener);
 };
 
diff --git a/packager/media/event/muxer_listener.h b/packager/media/event/muxer_listener.h
index e3e338a9d0..6712563d6e 100644
--- a/packager/media/event/muxer_listener.h
+++ b/packager/media/event/muxer_listener.h
@@ -6,6 +6,8 @@
 //
 // Event handler for events fired by Muxer.
 
+// TODO(rkuroiwa): Document using doxygen style comments.
+
 #ifndef MEDIA_EVENT_MUXER_LISTENER_H_
 #define MEDIA_EVENT_MUXER_LISTENER_H_
 
@@ -34,7 +36,24 @@ class MuxerListener {
 
   virtual ~MuxerListener() {};
 
-  // Called when muxing starts. This event happens before any other events.
+  // Called when the media's encryption information is ready. This should be
+  // called before OnMediaStart(), if the media is encrypted.
+  // All the parameters may be empty just to notify that the media is encrypted.
+  // |content_protection_uuid| is one of the UUIDs listed here
+  // http://dashif.org/identifiers/protection/. This should be in human
+  // readable form.
+  // |content_protection_name_version| is the DRM system and version name.
+  // For ISO BMFF (MP4) media:
+  // |default_key_id| is the default_KID in 'tenc' box. The format should
+  // be a vector of uint8_t, i.e. not (necessarily) human readable hex string.
+  // |pssh| is the whole 'pssh' box.
+  virtual void OnEncryptionInfoReady(
+      const std::string& content_protection_uuid,
+      const std::string& content_protection_name_version,
+      const std::vector<uint8_t>& default_key_id,
+      const std::vector<uint8_t>& pssh) = 0;
+
+  // Called when muxing starts.
   // For MPEG DASH Live profile, the initialization segment information is
   // available from StreamInfo.
   // |time_scale| is a reference time scale that overrides the time scale
@@ -42,8 +61,7 @@ class MuxerListener {
   virtual void OnMediaStart(const MuxerOptions& muxer_options,
                             const StreamInfo& stream_info,
                             uint32_t time_scale,
-                            ContainerType container_type,
-                            bool is_encrypted) = 0;
+                            ContainerType container_type) = 0;
 
   /// Called when the average sample duration of the media is determined.
   /// @param sample_duration in timescale of the media.
diff --git a/packager/media/event/muxer_listener_internal.cc b/packager/media/event/muxer_listener_internal.cc
index ca6cc5e7c3..a0539c0f61 100644
--- a/packager/media/event/muxer_listener_internal.cc
+++ b/packager/media/event/muxer_listener_internal.cc
@@ -201,6 +201,8 @@ bool SetVodInformation(bool has_init_range,
   return true;
 }
 
+// TODO(rkuroiwa): Move this logic to MpdBuilder? MuxerListener probably doesn't
+// need to know this.
 bool AddContentProtectionElements(MuxerListener::ContainerType container_type,
                                   const std::string& user_scheme_id_uri,
                                   MediaInfo* media_info) {
@@ -237,6 +239,36 @@ bool AddContentProtectionElements(MuxerListener::ContainerType container_type,
   return true;
 }
 
+void SetContentProtectionFields(
+    const std::string& content_protection_uuid,
+    const std::string& content_protection_name_version,
+    const std::string& default_key_id,
+    const std::string& pssh,
+    MediaInfo* media_info) {
+  DCHECK(media_info);
+  MediaInfo::ProtectedContent* protected_content =
+      media_info->mutable_protected_content();
+
+  if (!default_key_id.empty())
+    protected_content->set_default_key_id(default_key_id);
+
+  if (content_protection_uuid.empty() &&
+      content_protection_name_version.empty() && pssh.empty()) {
+    return;
+  }
+
+  MediaInfo::ProtectedContent::ContentProtectionEntry* entry =
+      protected_content->add_content_protection_entry();
+  if (!content_protection_uuid.empty())
+    entry->set_uuid(content_protection_uuid);
+
+  if (!content_protection_name_version.empty())
+    entry->set_name_version(content_protection_name_version);
+
+  if (!pssh.empty())
+    entry->set_pssh(pssh);
+}
+
 }  // namespace internal
 }  // namespace media
 }  // namespace edash_packager
diff --git a/packager/media/event/muxer_listener_internal.h b/packager/media/event/muxer_listener_internal.h
index a3e28d82ef..201eda62ed 100644
--- a/packager/media/event/muxer_listener_internal.h
+++ b/packager/media/event/muxer_listener_internal.h
@@ -54,6 +54,22 @@ bool AddContentProtectionElements(MuxerListener::ContainerType container_type,
                                   const std::string& user_scheme_id_uri,
                                   MediaInfo* media_info);
 
+/// @param content_protection_uuid is the UUID of the content protection
+///        in human readable form.
+/// @param content_protection_name_version is the DRM name and verion.
+/// @param default_key_id is the key ID for this media in hex (i.e. non-human
+///        readable, typically 16 bytes.)
+/// @param pssh is the pssh for the media in hex (i.e. non-human readable, raw
+///        'pssh' box.)
+/// @param media_info is where the content protection information is stored and
+///        cannot be null.
+void SetContentProtectionFields(
+    const std::string& content_protection_uuid,
+    const std::string& content_protection_name_version,
+    const std::string& default_key_id,
+    const std::string& pssh,
+    MediaInfo* media_info);
+
 }  // namespace internal
 }  // namespace media
 }  // namespace edash_packager
diff --git a/packager/media/event/vod_media_info_dump_muxer_listener.cc b/packager/media/event/vod_media_info_dump_muxer_listener.cc
index a52624f82e..e9e020e870 100644
--- a/packager/media/event/vod_media_info_dump_muxer_listener.cc
+++ b/packager/media/event/vod_media_info_dump_muxer_listener.cc
@@ -20,7 +20,7 @@ namespace media {
 
 VodMediaInfoDumpMuxerListener::VodMediaInfoDumpMuxerListener(
     const std::string& output_file_name)
-    : output_file_name_(output_file_name) {}
+    : output_file_name_(output_file_name), is_encrypted_(false) {}
 
 VodMediaInfoDumpMuxerListener::~VodMediaInfoDumpMuxerListener() {}
 
@@ -29,12 +29,23 @@ void VodMediaInfoDumpMuxerListener::SetContentProtectionSchemeIdUri(
   scheme_id_uri_ = scheme_id_uri;
 }
 
+void VodMediaInfoDumpMuxerListener::OnEncryptionInfoReady(
+    const std::string& content_protection_uuid,
+    const std::string& content_protection_name_version,
+    const std::vector<uint8_t>& default_key_id,
+    const std::vector<uint8_t>& pssh) {
+  content_protection_uuid_ = content_protection_uuid;
+  content_protection_name_version_ = content_protection_name_version;
+  default_key_id_.assign(default_key_id.begin(), default_key_id.end());
+  pssh_.assign(pssh.begin(), pssh.end());
+  is_encrypted_ = true;
+}
+
 void VodMediaInfoDumpMuxerListener::OnMediaStart(
     const MuxerOptions& muxer_options,
     const StreamInfo& stream_info,
     uint32_t time_scale,
-    ContainerType container_type,
-    bool is_encrypted) {
+    ContainerType container_type) {
   DCHECK(muxer_options.single_segment);
   media_info_.reset(new MediaInfo());
   if (!internal::GenerateMediaInfo(muxer_options,
@@ -46,7 +57,13 @@ void VodMediaInfoDumpMuxerListener::OnMediaStart(
     return;
   }
 
-  if (is_encrypted) {
+  if (is_encrypted_) {
+    internal::SetContentProtectionFields(
+        content_protection_uuid_, content_protection_name_version_,
+        default_key_id_, pssh_, media_info_.get());
+  }
+
+  if (is_encrypted_) {
     if (!internal::AddContentProtectionElements(
             container_type, scheme_id_uri_, media_info_.get())) {
       LOG(ERROR) << "Failed to add content protection elements.";
diff --git a/packager/media/event/vod_media_info_dump_muxer_listener.h b/packager/media/event/vod_media_info_dump_muxer_listener.h
index 144957366d..552d822d1f 100644
--- a/packager/media/event/vod_media_info_dump_muxer_listener.h
+++ b/packager/media/event/vod_media_info_dump_muxer_listener.h
@@ -36,11 +36,16 @@ class VodMediaInfoDumpMuxerListener : public MuxerListener {
 
   /// @name MuxerListener implementation overrides.
   /// @{
-  virtual void OnMediaStart(const MuxerOptions& muxer_options,
-                            const StreamInfo& stream_info,
-                            uint32_t time_scale,
-                            ContainerType container_type,
-                            bool is_encrypted) OVERRIDE;
+  virtual void OnEncryptionInfoReady(
+      const std::string& content_protection_uuid,
+      const std::string& content_protection_name_version,
+      const std::vector<uint8_t>& default_key_id,
+      const std::vector<uint8_t>& pssh) OVERRIDE;
+  virtual void OnMediaStart(
+      const MuxerOptions& muxer_options,
+      const StreamInfo& stream_info,
+      uint32_t time_scale,
+      ContainerType container_type) OVERRIDE;
   virtual void OnSampleDurationReady(uint32_t sample_duration) OVERRIDE;
   virtual void OnMediaEnd(bool has_init_range,
                           uint64_t init_range_start,
@@ -63,6 +68,13 @@ class VodMediaInfoDumpMuxerListener : public MuxerListener {
   std::string scheme_id_uri_;
   scoped_ptr<MediaInfo> media_info_;
 
+  bool is_encrypted_;
+  // Storage for values passed to OnEncryptionInfoReady().
+  std::string content_protection_uuid_;
+  std::string content_protection_name_version_;
+  std::string default_key_id_;
+  std::string pssh_;
+
   DISALLOW_COPY_AND_ASSIGN(VodMediaInfoDumpMuxerListener);
 };
 
diff --git a/packager/media/event/vod_media_info_dump_muxer_listener_unittest.cc b/packager/media/event/vod_media_info_dump_muxer_listener_unittest.cc
index 20d37f44a9..3fd535533f 100644
--- a/packager/media/event/vod_media_info_dump_muxer_listener_unittest.cc
+++ b/packager/media/event/vod_media_info_dump_muxer_listener_unittest.cc
@@ -20,6 +20,19 @@
 
 namespace {
 const bool kEnableEncryption = true;
+// '_default_key_id_' (length 16).
+const uint8_t kBogusDefaultKeyId[] = {0x5f, 0x64, 0x65, 0x66, 0x61, 0x75,
+                                      0x6c, 0x74, 0x5f, 0x6b, 0x65, 0x79,
+                                      0x5f, 0x69, 0x64, 0x5f};
+// 'pssh'. Not a valid pssh box.
+const uint8_t kInvalidPssh[] = {
+  0x70, 0x73, 0x73, 0x68
+};
+
+// This should be in the uuid field of the protobuf. This is not a valid UUID
+// format but the protobof generation shouldn't care.
+const char kTestUUID[] = "myuuid";
+const char kTestContentProtectionName[] = "MyContentProtection version 1";
 }  // namespace
 
 namespace edash_packager {
@@ -178,11 +191,21 @@ class VodMediaInfoDumpMuxerListenerTest : public ::testing::Test {
     MuxerOptions muxer_options;
     SetDefaultMuxerOptionsValues(&muxer_options);
     const uint32_t kReferenceTimeScale = 1000;
-    listener_->OnMediaStart(muxer_options,
-                            stream_info,
-                            kReferenceTimeScale,
-                            MuxerListener::kContainerMp4,
-                            enable_encryption);
+    if (enable_encryption) {
+      std::vector<uint8_t> bogus_default_key_id(
+          kBogusDefaultKeyId,
+          kBogusDefaultKeyId + arraysize(kBogusDefaultKeyId));
+
+      // This isn't a valid pssh box but the MediaInfo protobuf creator
+      // shouldn't worry about it.
+      std::vector<uint8_t> invalid_pssh(kInvalidPssh,
+                                        kInvalidPssh + arraysize(kInvalidPssh));
+
+      listener_->OnEncryptionInfoReady(kTestUUID, kTestContentProtectionName,
+                                       bogus_default_key_id, invalid_pssh);
+    }
+    listener_->OnMediaStart(muxer_options, stream_info, kReferenceTimeScale,
+                            MuxerListener::kContainerMp4);
   }
 
   void FireOnMediaEndWithParams(const OnMediaEndParameters& params) {
@@ -285,7 +308,16 @@ TEST_F(VodMediaInfoDumpMuxerListenerTest, EncryptedStream_Normal) {
       "reference_time_scale: 1000\n"
       "container_type: 1\n"
       "media_file_name: 'test_output_file_name.mp4'\n"
-      "media_duration_seconds: 10.5\n";
+      "media_duration_seconds: 10.5\n"
+      "protected_content {\n"
+      "  content_protection_entry {\n"
+      "    uuid: 'myuuid'\n"
+      "    name_version: 'MyContentProtection version 1'\n"
+      "    pssh: 'pssh'\n"
+      "  }\n"
+      "  default_key_id: '_default_key_id_'\n"
+      "}\n";
+
   ASSERT_NO_FATAL_FAILURE(ExpectTempFileToEqual(kExpectedProtobufOutput));
 }
 
diff --git a/packager/media/formats/mp4/mp4_muxer.cc b/packager/media/formats/mp4/mp4_muxer.cc
index bc3ec080c6..f2386e3f13 100644
--- a/packager/media/formats/mp4/mp4_muxer.cc
+++ b/packager/media/formats/mp4/mp4_muxer.cc
@@ -244,8 +244,7 @@ void MP4Muxer::FireOnMediaStartEvent() {
   muxer_listener()->OnMediaStart(options(),
                                  *streams().front()->info(),
                                  timescale,
-                                 MuxerListener::kContainerMp4,
-                                 encryption_key_source() != NULL);
+                                 MuxerListener::kContainerMp4);
 }
 
 void MP4Muxer::FireOnMediaEndEvent() {
diff --git a/packager/media/formats/mp4/segmenter.cc b/packager/media/formats/mp4/segmenter.cc
index 419e3eae81..ea9b004b7b 100644
--- a/packager/media/formats/mp4/segmenter.cc
+++ b/packager/media/formats/mp4/segmenter.cc
@@ -15,6 +15,7 @@
 #include "packager/media/base/media_stream.h"
 #include "packager/media/base/muxer_options.h"
 #include "packager/media/base/video_stream_info.h"
+#include "packager/media/event/muxer_listener.h"
 #include "packager/media/event/progress_listener.h"
 #include "packager/media/formats/mp4/box_definitions.h"
 #include "packager/media/formats/mp4/key_rotation_fragmenter.h"
@@ -196,6 +197,13 @@ Status Segmenter::Initialize(const std::vector<MediaStream*>& streams,
     if (moov_->pssh.empty()) {
       moov_->pssh.resize(1);
       moov_->pssh[0].raw_box = encryption_key->pssh;
+
+      // Also only one default key id.
+      if (muxer_listener_) {
+        muxer_listener_->OnEncryptionInfoReady(
+            encryption_key_source->UUID(), encryption_key_source->SystemName(),
+            encryption_key->key_id, encryption_key->pssh);
+      }
     }
 
     fragmenters_[i] = new EncryptingFragmenter(
diff --git a/packager/mpd/base/media_info.proto b/packager/mpd/base/media_info.proto
index eeffc609c2..894633e9fc 100644
--- a/packager/mpd/base/media_info.proto
+++ b/packager/mpd/base/media_info.proto
@@ -55,6 +55,26 @@ message MediaInfo {
     optional string language = 2;
   }
 
+  message ProtectedContent {
+    message ContentProtectionEntry {
+      // Human readable UUID of the DRM.
+      optional string uuid = 1;
+      // Human readable DRM name and version string.
+      // e.g. "My Content Protection v1.0"
+      optional string name_version = 2;
+      // The raw 'pssh' box for the media.
+      optional bytes pssh = 3;
+    }
+
+    // The default key ID for the encrypted media.
+    optional bytes default_key_id = 1;
+    repeated ContentProtectionEntry content_protection_entry = 2;
+  }
+
+  // TODO(rkuroiwa): Remove this. <ContentProtection> element that must be added
+  // should be done by directly using the MpdBuilder interface.
+  // Use this to specify ContentProtection elements that should be set in
+  // the MPD, if ContentProtectionEntry is not sufficient.
   message ContentProtectionXml {
     message AttributeNameValuePair {
       optional string name = 1;
@@ -85,6 +105,10 @@ message MediaInfo {
   optional TextInfo text_info = 4;
   repeated ContentProtectionXml content_protections = 5;
 
+  // This is set if the content is protected with a content protection,
+  // i.e. encrypted.
+  optional ProtectedContent protected_content = 15;
+
   // This is the reference time scale if there are multiple VideoInfo and/or
   // AudioInfo.
   optional uint32 reference_time_scale = 13;