diff --git a/sharing/certificates/BUILD b/sharing/certificates/BUILD
index 26b5291d..40f09113 100644
--- a/sharing/certificates/BUILD
+++ b/sharing/certificates/BUILD
@@ -41,12 +41,13 @@ cc_library(
     deps = [
         "//internal/base",
         "//internal/crypto_cros",
+        "//internal/flags:nearby_flags",
         "//internal/platform:types",
         "//internal/platform/implementation:account_manager",
-        "//internal/platform/implementation:types",
         "//sharing/common",
         "//sharing/common:enum",
         "//sharing/contacts",
+        "//sharing/flags/generated:generated_flags",
         "//sharing/internal/api:platform",
         "//sharing/internal/base",
         "//sharing/internal/public:logging",
@@ -114,13 +115,14 @@ cc_test(
     deps = [
         ":certificates",
         ":test_support",
+        "//internal/flags:nearby_flags",
         "//internal/platform/implementation:account_manager",
-        "//internal/platform/implementation:types",
         "//internal/platform/implementation/g3",  # fixdeps: keep
         "//internal/test",
         "//sharing/common",
         "//sharing/common:enum",
         "//sharing/contacts:test_support",
+        "//sharing/flags/generated:generated_flags",
         "//sharing/internal/api:mock_sharing_platform",
         "//sharing/internal/public:logging",
         "//sharing/internal/test:nearby_test",
diff --git a/sharing/certificates/nearby_share_certificate_manager_impl.cc b/sharing/certificates/nearby_share_certificate_manager_impl.cc
index fdb94d23..4736cfe4 100644
--- a/sharing/certificates/nearby_share_certificate_manager_impl.cc
+++ b/sharing/certificates/nearby_share_certificate_manager_impl.cc
@@ -37,6 +37,7 @@
 #include "absl/synchronization/notification.h"
 #include "absl/time/time.h"
 #include "absl/types/span.h"
+#include "internal/flags/nearby_flags.h"
 #include "internal/platform/implementation/account_manager.h"
 #include "sharing/certificates/common.h"
 #include "sharing/certificates/constants.h"
@@ -48,6 +49,7 @@
 #include "sharing/certificates/nearby_share_private_certificate.h"
 #include "sharing/common/nearby_share_prefs.h"
 #include "sharing/contacts/nearby_share_contact_manager.h"
+#include "sharing/flags/generated/nearby_sharing_feature_flags.h"
 #include "sharing/internal/api/bluetooth_adapter.h"
 #include "sharing/internal/api/preference_manager.h"
 #include "sharing/internal/api/public_certificate_database.h"
@@ -384,11 +386,11 @@ void NearbyShareCertificateManagerImpl::DownloadPublicCertificates() {
 }
 
 void NearbyShareCertificateManagerImpl::UploadLocalDeviceCertificates() {
-  executor_->PostTask([&]() {
-    NL_LOG(INFO) << __func__ << ": Start to upload local device certificates.";
+  executor_->PostTask([this]() {
+    LOG(INFO) << __func__ << ": Start to upload local device certificates.";
 
     if (!is_running()) {
-      NL_LOG(WARNING)
+      LOG(WARNING)
           << __func__
           << ": Ignore to upload local device certificates due to manager is "
              "not running.";
@@ -396,10 +398,9 @@ void NearbyShareCertificateManagerImpl::UploadLocalDeviceCertificates() {
     }
 
     if (!account_manager_.GetCurrentAccount().has_value()) {
-      NL_LOG(WARNING)
-          << __func__
-          << ": Ignore to upload local device certificates due to no "
-             "login account.";
+      LOG(WARNING) << __func__
+                   << ": Ignore to upload local device certificates due to no "
+                      "login account.";
       upload_local_device_certificates_scheduler_->HandleResult(
           /*success=*/true);
       return;
@@ -413,20 +414,50 @@ void NearbyShareCertificateManagerImpl::UploadLocalDeviceCertificates() {
       public_certs.push_back(*private_cert.ToPublicCertificate());
     }
 
-    NL_LOG(INFO) << __func__ << ": Uploading " << public_certs.size()
-                 << " local device certificates.";
     bool upload_certificates_result = false;
     absl::Notification notification;
-    local_device_data_manager_->UploadCertificates(
-        std::move(public_certs), [&](bool success) {
-          upload_certificates_result = success;
-          notification.Notify();
-        });
+    if (NearbyFlags::GetInstance().GetBoolFlag(
+            config_package_nearby::nearby_sharing_feature::
+                kCallNearbyIdentityApi)) {
+      LOG(INFO) << __func__ << ": [Call Identity API] PublishDevice: upload "
+                << public_certs.size() << " local device certificates.";
+      local_device_data_manager_->PublishDevice(
+          std::move(public_certs), call_publish_device_after_certs_regen_,
+          [this, &upload_certificates_result, &notification](
+              bool success, bool contact_removed) {
+            upload_certificates_result = success;
+            call_publish_device_after_certs_regen_ = contact_removed;
+            notification.Notify();
+          });
+    } else {
+      LOG(INFO) << __func__
+                << ": [Call NearbyShare API] UploadCertificates: upload"
+                << public_certs.size() << " local device certificates.";
+      local_device_data_manager_->UploadCertificates(
+          std::move(public_certs), [&](bool success) {
+            upload_certificates_result = success;
+            notification.Notify();
+          });
+    }
     notification.WaitForNotification();
-    NL_LOG(INFO) << __func__ << ": Upload of local device certificates "
-                 << (upload_certificates_result ? "succeeded" : "failed.");
+    LOG(INFO) << __func__ << ": Upload of local device certificates "
+              << (upload_certificates_result ? "succeeded" : "failed.");
     upload_local_device_certificates_scheduler_->HandleResult(
         upload_certificates_result);
+
+    // TODO(b/373780923): add Unit test for the two RPC calls and add a cap to
+    // the number of time you can keep calling PublishDevice due to contacts
+    // changes (it could indicate a server bug).
+    if (call_publish_device_after_certs_regen_ &&
+        NearbyFlags::GetInstance().GetBoolFlag(
+            config_package_nearby::nearby_sharing_feature::
+                kCallNearbyIdentityApi)) {
+      LOG(INFO) << __func__
+                << ": [Call Identity API] Another call to PublishDevice after "
+                   "regenerating all Private certificates: ";
+      certificate_storage_->ClearPrivateCertificates();
+      private_certificate_expiration_scheduler_->MakeImmediateRequest();
+    }
   });
 }
 
diff --git a/sharing/certificates/nearby_share_certificate_manager_impl.h b/sharing/certificates/nearby_share_certificate_manager_impl.h
index 67baf99a..f8580359 100644
--- a/sharing/certificates/nearby_share_certificate_manager_impl.h
+++ b/sharing/certificates/nearby_share_certificate_manager_impl.h
@@ -213,6 +213,11 @@ class NearbyShareCertificateManagerImpl
   std::unique_ptr<NearbyShareScheduler> download_public_certificates_scheduler_;
 
   std::unique_ptr<TaskRunner> executor_;
+  // Whether we need to regenerate the certificates and make another
+  // PublishDevice call. At every PublishDevice call, we check
+  // PublishDeviceResponse to see if contacts are removed. In which case, we
+  // need to regenerate the certificates and make another PublishDevice call.
+  bool call_publish_device_after_certs_regen_ = false;
 };
 
 }  // namespace sharing
diff --git a/sharing/certificates/nearby_share_certificate_manager_impl_test.cc b/sharing/certificates/nearby_share_certificate_manager_impl_test.cc
index ca12e6ff..3cc0876e 100644
--- a/sharing/certificates/nearby_share_certificate_manager_impl_test.cc
+++ b/sharing/certificates/nearby_share_certificate_manager_impl_test.cc
@@ -35,6 +35,7 @@
 #include "absl/strings/string_view.h"
 #include "absl/time/time.h"
 #include "absl/types/span.h"
+#include "internal/flags/nearby_flags.h"
 #include "internal/platform/implementation/account_manager.h"
 #include "internal/test/fake_account_manager.h"
 #include "sharing/certificates/constants.h"
@@ -47,6 +48,7 @@
 #include "sharing/certificates/test_util.h"
 #include "sharing/common/nearby_share_prefs.h"
 #include "sharing/contacts/fake_nearby_share_contact_manager.h"
+#include "sharing/flags/generated/nearby_sharing_feature_flags.h"
 #include "sharing/internal/api/fake_nearby_share_client.h"
 #include "sharing/internal/api/mock_sharing_platform.h"
 #include "sharing/internal/public/logging.h"
@@ -167,6 +169,7 @@ class NearbyShareCertificateManagerImplTest
     cert_manager_->RemoveObserver(this);
     NearbyShareSchedulerFactory::SetFactoryForTesting(nullptr);
     NearbyShareCertificateStorageImpl::Factory::SetFactoryForTesting(nullptr);
+    NearbyFlags::GetInstance().ResetOverridedValues();
   }
 
   void SetBluetoothMacAddress(absl::string_view bluetooth_mac_address) {
@@ -323,6 +326,28 @@ class NearbyShareCertificateManagerImplTest
     EXPECT_EQ(upload_scheduler_->handled_results().back(), success);
   }
 
+  void RunPublishDevice(bool success) {
+    size_t initial_num_upload_calls =
+        local_device_data_manager_->publish_device_calls().size();
+    local_device_data_manager_->SetPublishDeviceResult(success);
+    size_t initial_num_handled_results =
+        upload_scheduler_->handled_results().size();
+
+    upload_scheduler_->InvokeRequestCallback();
+    Sync();
+    EXPECT_EQ(local_device_data_manager_->publish_device_calls().size(),
+              initial_num_upload_calls + 1);
+
+    EXPECT_EQ(local_device_data_manager_->publish_device_calls()
+                  .back()
+                  .certificates.size(),
+              3 * kNearbyShareNumPrivateCertificates);
+
+    EXPECT_EQ(upload_scheduler_->handled_results().size(),
+              initial_num_handled_results + 1);
+    EXPECT_EQ(upload_scheduler_->handled_results().back(), success);
+  }
+
   // Test downloading public certificates with or without errors. The RPC is
   // paginated, and |num_pages| will be simulated. Any failures, as indicated by
   // |result|, will be simulated on the last page.
@@ -703,6 +728,19 @@ TEST_F(NearbyShareCertificateManagerImplTest,
   VerifyPrivateCertificates(/*expected_metadata=*/GetNearbyShareTestMetadata());
 }
 
+TEST_F(NearbyShareCertificateManagerImplTest,
+       RefreshPrivateCertificates_PublishDevice_NoCertificates_UploadSuccess) {
+  NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      config_package_nearby::nearby_sharing_feature::kCallNearbyIdentityApi,
+      true);
+  cert_store_->ReplacePrivateCertificates({});
+
+  HandlePrivateCertificateRefresh(/*expect_private_cert_refresh=*/true,
+                                  /*expected_success=*/true);
+  RunPublishDevice(/*success=*/true);
+  VerifyPrivateCertificates(/*expected_metadata=*/GetNearbyShareTestMetadata());
+}
+
 TEST_F(NearbyShareCertificateManagerImplTest,
        RefreshPrivateCertificates_NoCertificates_UploadFailure) {
   cert_store_->ReplacePrivateCertificates({});
diff --git a/sharing/contacts/BUILD b/sharing/contacts/BUILD
index b22d00f2..bf3a3e9b 100644
--- a/sharing/contacts/BUILD
+++ b/sharing/contacts/BUILD
@@ -30,9 +30,11 @@ cc_library(
     deps = [
         "//internal/base",
         "//internal/crypto_cros",
+        "//internal/flags:nearby_flags",
         "//internal/platform:types",
         "//internal/platform/implementation:account_manager",
         "//sharing/common",
+        "//sharing/flags/generated:generated_flags",
         "//sharing/internal/api:platform",
         "//sharing/internal/base",
         "//sharing/internal/public:logging",
@@ -43,7 +45,6 @@ cc_library(
         "@com_google_absl//absl/functional:any_invocable",
         "@com_google_absl//absl/functional:bind_front",
         "@com_google_absl//absl/memory",
-        "@com_google_absl//absl/status",
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
         "@com_google_absl//absl/synchronization",
diff --git a/sharing/contacts/nearby_share_contact_manager_impl.cc b/sharing/contacts/nearby_share_contact_manager_impl.cc
index 07afb338..fe07c2c4 100644
--- a/sharing/contacts/nearby_share_contact_manager_impl.cc
+++ b/sharing/contacts/nearby_share_contact_manager_impl.cc
@@ -31,11 +31,13 @@
 #include "absl/synchronization/notification.h"
 #include "absl/time/time.h"
 #include "internal/crypto_cros/secure_hash.h"
+#include "internal/flags/nearby_flags.h"
 #include "internal/platform/clock.h"
 #include "internal/platform/implementation/account_manager.h"
 #include "sharing/common/nearby_share_prefs.h"
 #include "sharing/contacts/nearby_share_contact_manager.h"
 #include "sharing/contacts/nearby_share_contacts_sorter.h"
+#include "sharing/flags/generated/nearby_sharing_feature_flags.h"
 #include "sharing/internal/api/preference_manager.h"
 #include "sharing/internal/api/sharing_rpc_client.h"
 #include "sharing/internal/base/encode.h"
@@ -172,7 +174,10 @@ NearbyShareContactManagerImpl::NearbyShareContactManagerImpl(
               /*require_connectivity=*/true,
               prefs::kNearbySharingSchedulerContactDownloadAndUploadName,
               [&] { DownloadContacts(); })),
-      executor_(context->CreateSequencedTaskRunner()) {}
+      executor_(context->CreateSequencedTaskRunner()),
+      use_identity_api_(NearbyFlags::GetInstance().GetBoolFlag(
+          config_package_nearby::nearby_sharing_feature::
+              kCallNearbyIdentityApi)) {}
 
 NearbyShareContactManagerImpl::~NearbyShareContactManagerImpl() = default;
 
@@ -230,6 +235,10 @@ void NearbyShareContactManagerImpl::ContactDownloadContext::FetchNextPage() {
 }
 
 void NearbyShareContactManagerImpl::DownloadContacts() {
+  if (use_identity_api_) {
+    LOG(INFO) << __func__ << ": [Call Identity API] Skipping DownloadContacts";
+    return;
+  }
   executor_->PostTask([this]() {
     NL_LOG(INFO) << __func__ << ": Start to download contacts";
     if (!is_running()) {
@@ -287,10 +296,22 @@ void NearbyShareContactManagerImpl::GetContacts(ContactsCallback callback) {
 }
 
 void NearbyShareContactManagerImpl::OnStart() {
+  if (use_identity_api_) {
+    LOG(INFO) << __func__
+              << ": [Call Identity API] Skipping "
+                 "contact_download_and_upload_scheduler start.";
+    return;
+  }
   contact_download_and_upload_scheduler_->Start();
 }
 
 void NearbyShareContactManagerImpl::OnStop() {
+  if (use_identity_api_) {
+    LOG(INFO) << __func__
+              << ": [Call Identity API] Skipping "
+                 "contact_download_and_upload_scheduler stop.";
+    return;
+  }
   contact_download_and_upload_scheduler_->Stop();
 }
 
diff --git a/sharing/contacts/nearby_share_contact_manager_impl.h b/sharing/contacts/nearby_share_contact_manager_impl.h
index 7bf9d329..9697da8c 100644
--- a/sharing/contacts/nearby_share_contact_manager_impl.h
+++ b/sharing/contacts/nearby_share_contact_manager_impl.h
@@ -149,6 +149,9 @@ class NearbyShareContactManagerImpl : public NearbyShareContactManager {
   std::unique_ptr<NearbyShareScheduler> contact_download_and_upload_scheduler_;
 
   std::unique_ptr<TaskRunner> executor_ = nullptr;
+  // Identity API does not support contacts upload/download. So essentially
+  // contact manager is inactive.
+  bool use_identity_api_ = false;
 };
 
 }  // namespace sharing
diff --git a/sharing/local_device_data/BUILD b/sharing/local_device_data/BUILD
index 46f9a213..c599a203 100644
--- a/sharing/local_device_data/BUILD
+++ b/sharing/local_device_data/BUILD
@@ -30,19 +30,23 @@ cc_library(
         "//internal/platform:types",
         "//internal/platform/implementation:account_manager",
         "//internal/platform/implementation:types",
+        "//proto/identity/v1:resources_cc_proto",
+        "//proto/identity/v1:rpcs_cc_proto",
         "//sharing/common",
         "//sharing/common:enum",
         "//sharing/internal/api:platform",
         "//sharing/internal/base:utf_utils",
+        "//sharing/internal/impl/common:nearby_identity_grpc_client",
         "//sharing/internal/public:logging",
         "//sharing/internal/public:types",
         "//sharing/proto:share_cc_proto",
-        "//sharing/scheduling",
+        "//util/hash:highway_fingerprint",
+        "@com_google_absl//absl/algorithm",
+        "@com_google_absl//absl/functional:any_invocable",
         "@com_google_absl//absl/memory",
         "@com_google_absl//absl/random",
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
-        "@com_google_absl//absl/time",
     ],
 )
 
@@ -63,7 +67,6 @@ cc_library(
         "//sharing/internal/public:types",
         "//sharing/proto:share_cc_proto",
         "@com_google_absl//absl/strings",
-        "@com_google_absl//absl/types:optional",
     ],
 )
 
@@ -77,9 +80,12 @@ cc_test(
         "//internal/platform/implementation:account_manager",
         "//internal/platform/implementation/g3",  # fixdeps: keep
         "//internal/test",
+        "//proto/identity/v1:resources_cc_proto",
+        "//proto/identity/v1:rpcs_cc_proto",
         "//sharing/common",
         "//sharing/common:enum",
         "//sharing/internal/api:mock_sharing_platform",
+        "//sharing/internal/public:logging",
         "//sharing/internal/test:nearby_test",
         "//sharing/proto:share_cc_proto",
         "//sharing/scheduling",
diff --git a/sharing/local_device_data/fake_nearby_share_local_device_data_manager.cc b/sharing/local_device_data/fake_nearby_share_local_device_data_manager.cc
index 4f7467c7..a9f60840 100644
--- a/sharing/local_device_data/fake_nearby_share_local_device_data_manager.cc
+++ b/sharing/local_device_data/fake_nearby_share_local_device_data_manager.cc
@@ -20,7 +20,6 @@
 #include <vector>
 
 #include "absl/strings/string_view.h"
-#include "absl/types/optional.h"
 #include "sharing/common/nearby_share_enums.h"
 #include "sharing/internal/api/sharing_rpc_client.h"
 #include "sharing/internal/public/context.h"
@@ -132,5 +131,15 @@ void FakeNearbyShareLocalDeviceDataManager::UploadCertificates(
   }
 }
 
+void FakeNearbyShareLocalDeviceDataManager::PublishDevice(
+    std::vector<nearby::sharing::proto::PublicCertificate> certificates,
+    bool is_second_call, PublishDeviceCallback callback) {
+  publish_device_calls_.emplace_back(std::move(certificates), is_second_call,
+                                     callback);
+  if (is_sync_mode_) {
+    callback(publish_device_result_, false);
+  }
+};
+
 }  // namespace sharing
 }  // namespace nearby
diff --git a/sharing/local_device_data/fake_nearby_share_local_device_data_manager.h b/sharing/local_device_data/fake_nearby_share_local_device_data_manager.h
index a0fb4317..960cfbe4 100644
--- a/sharing/local_device_data/fake_nearby_share_local_device_data_manager.h
+++ b/sharing/local_device_data/fake_nearby_share_local_device_data_manager.h
@@ -90,6 +90,19 @@ class FakeNearbyShareLocalDeviceDataManager
     UploadCompleteCallback callback;
   };
 
+  struct PublishDeviceCall {
+    PublishDeviceCall(
+        std::vector<nearby::sharing::proto::PublicCertificate> certificates,
+        bool is_second_call, PublishDeviceCallback callback)
+        : certificates(std::move(certificates)),
+          callback(std::move(callback)) {}
+    PublishDeviceCall(PublishDeviceCall&&) = default;
+    ~PublishDeviceCall() = default;
+
+    std::vector<nearby::sharing::proto::PublicCertificate> certificates;
+    PublishDeviceCallback callback;
+  };
+
   explicit FakeNearbyShareLocalDeviceDataManager(
       absl::string_view default_device_name);
   ~FakeNearbyShareLocalDeviceDataManager() override;
@@ -106,6 +119,10 @@ class FakeNearbyShareLocalDeviceDataManager
       std::vector<nearby::sharing::proto::PublicCertificate> certificates,
       UploadCompleteCallback callback) override;
 
+  void PublishDevice(
+      std::vector<nearby::sharing::proto::PublicCertificate> certificates,
+      bool is_second_call, PublishDeviceCallback callback) override;
+
   // Make protected observer-notification methods from the base class public in
   // this fake class.
   using NearbyShareLocalDeviceDataManager::NotifyLocalDeviceDataChanged;
@@ -120,6 +137,10 @@ class FakeNearbyShareLocalDeviceDataManager
     return upload_certificates_calls_;
   }
 
+  std::vector<PublishDeviceCall>& publish_device_calls() {
+    return publish_device_calls_;
+  }
+
   void set_next_validation_result(DeviceNameValidationResult result) {
     next_validation_result_ = result;
   }
@@ -135,6 +156,10 @@ class FakeNearbyShareLocalDeviceDataManager
     upload_certificate_result_ = upload_certificate_result;
   }
 
+  void SetPublishDeviceResult(bool publish_device_result) {
+    publish_device_result_ = publish_device_result;
+  }
+
  private:
   // NearbyShareLocalDeviceDataManager:
 
@@ -142,6 +167,7 @@ class FakeNearbyShareLocalDeviceDataManager
   std::string device_name_;
   std::vector<UploadContactsCall> upload_contacts_calls_;
   std::vector<UploadCertificatesCall> upload_certificates_calls_;
+  std::vector<PublishDeviceCall> publish_device_calls_;
   DeviceNameValidationResult next_validation_result_ =
       DeviceNameValidationResult::kValid;
 
@@ -149,6 +175,7 @@ class FakeNearbyShareLocalDeviceDataManager
   bool is_sync_mode_ = false;
   bool upload_contact_result_ = false;
   bool upload_certificate_result_ = false;
+  bool publish_device_result_ = false;
 };
 
 }  // namespace sharing
diff --git a/sharing/local_device_data/nearby_share_local_device_data_manager.h b/sharing/local_device_data/nearby_share_local_device_data_manager.h
index 1d6a3de7..0f7b7bc3 100644
--- a/sharing/local_device_data/nearby_share_local_device_data_manager.h
+++ b/sharing/local_device_data/nearby_share_local_device_data_manager.h
@@ -47,6 +47,8 @@ class NearbyShareLocalDeviceDataManager {
   };
 
   using UploadCompleteCallback = std::function<void(bool success)>;
+  using PublishDeviceCallback =
+      std::function<void(bool success, bool contact_removed)>;
 
   NearbyShareLocalDeviceDataManager();
   virtual ~NearbyShareLocalDeviceDataManager();
@@ -96,6 +98,12 @@ class NearbyShareLocalDeviceDataManager {
       std::vector<nearby::sharing::proto::PublicCertificate> certificates,
       UploadCompleteCallback callback) = 0;
 
+  // Calls Identity PublishDevice RPC to upload local device's public
+  // certificates.
+  virtual void PublishDevice(
+      std::vector<nearby::sharing::proto::PublicCertificate> certificates,
+      bool force_update_contacts, PublishDeviceCallback callback) = 0;
+
  protected:
   void NotifyLocalDeviceDataChanged(bool did_device_name_change,
                                     bool did_full_name_change,
diff --git a/sharing/local_device_data/nearby_share_local_device_data_manager_impl.cc b/sharing/local_device_data/nearby_share_local_device_data_manager_impl.cc
index 25af9f38..894a75a5 100644
--- a/sharing/local_device_data/nearby_share_local_device_data_manager_impl.cc
+++ b/sharing/local_device_data/nearby_share_local_device_data_manager_impl.cc
@@ -25,16 +25,18 @@
 #include <utility>
 #include <vector>
 
+#include "absl/algorithm/algorithm.h"
 #include "absl/memory/memory.h"
 #include "absl/random/random.h"
 #include "absl/status/statusor.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "absl/strings/substitute.h"
-#include "absl/time/time.h"
 #include "internal/platform/device_info.h"
 #include "internal/platform/implementation/account_manager.h"
 #include "internal/platform/implementation/device_info.h"
+#include "proto/identity/v1/resources.pb.h"
+#include "proto/identity/v1/rpcs.pb.h"
 #include "sharing/common/nearby_share_enums.h"
 #include "sharing/common/nearby_share_prefs.h"
 #include "sharing/internal/api/preference_manager.h"
@@ -46,12 +48,14 @@
 #include "sharing/proto/device_rpc.pb.h"
 #include "sharing/proto/field_mask.pb.h"
 #include "sharing/proto/rpc_resources.pb.h"
-#include "sharing/scheduling/nearby_share_scheduler.h"
-#include "sharing/scheduling/nearby_share_scheduler_factory.h"
+#include "sharing/proto/timestamp.pb.h"
+#include "util/hash/highway_fingerprint.h"
 
 namespace nearby {
 namespace sharing {
 namespace {
+using ::google::nearby::identity::v1::PublishDeviceRequest;
+using ::google::nearby::identity::v1::PublishDeviceResponse;
 using ::nearby::api::DeviceInfo;
 using ::nearby::sharing::api::PreferenceManager;
 using ::nearby::sharing::api::SharingRpcClientFactory;
@@ -131,6 +135,7 @@ NearbyShareLocalDeviceDataManagerImpl::NearbyShareLocalDeviceDataManagerImpl(
       account_manager_(account_manager),
       device_info_(device_info),
       nearby_share_client_(rpc_client_factory->CreateInstance()),
+      nearby_identity_client_(rpc_client_factory->CreateIdentityInstance()),
       device_id_(GetId()),
       executor_(context->CreateSequencedTaskRunner()) {}
 
@@ -228,6 +233,107 @@ void NearbyShareLocalDeviceDataManagerImpl::UploadContacts(
             });
       });
 }
+void NearbyShareLocalDeviceDataManagerImpl::PublishDevice(
+    std::vector<nearby::sharing::proto::PublicCertificate> certificates,
+    bool force_update_contacts, PublishDeviceCallback callback) {
+  executor_->PostTask([this, force_update_contacts,
+                       certificates = std::move(certificates),
+                       callback = std::move(callback)]() mutable {
+    if (!is_running()) {
+      LOG(WARNING) << __func__
+                   << ": [Call Identity API] no-op as manager is stopped.";
+      callback(/*success=*/false, /*contact_removed=*/false);
+      return;
+    }
+    LOG(INFO) << __func__ << ": [Call Identity API]  Upload "
+              << certificates.size() << " certificates.";
+
+    PublishDeviceRequest request;
+    request.mutable_device()->set_name(absl::StrCat("devices/", device_id_));
+    LOG(INFO) << __func__
+              << ": [Call Identity API] PublishDeviceRequest with Device.name: "
+              << request.device().name();
+    request.mutable_device()->set_display_name(GetDeviceName());
+    // Force update contacts call is right after CONTACT_GOOGLE_CONTACT_LATEST
+    // call and can use CONTACT_GOOGLE_CONTACT to save server side computation.
+
+    request.mutable_device()->set_contact(
+        force_update_contacts
+            ? google::nearby::identity::v1::Device::CONTACT_GOOGLE_CONTACT
+            : google::nearby::identity::v1::Device::
+                  CONTACT_GOOGLE_CONTACT_LATEST);
+
+    auto* new_self_credential =
+        request.mutable_device()->add_per_visibility_shared_credentials();
+    new_self_credential->set_visibility(
+        google::nearby::identity::v1::PerVisibilitySharedCredentials::
+            VISIBILITY_SELF);
+    auto* new_contacts_credential =
+        request.mutable_device()->add_per_visibility_shared_credentials();
+    new_contacts_credential->set_visibility(
+        google::nearby::identity::v1::PerVisibilitySharedCredentials::
+            VISIBILITY_CONTACTS);
+
+    for (const auto& certificate : certificates) {
+      google::nearby::identity::v1::SharedCredential* shared_credential;
+      if (certificate.for_self_share()) {
+        shared_credential = new_self_credential->add_shared_credentials();
+        LOG(INFO) << __func__ << ": [Call Identity API] self_share";
+      } else {
+        shared_credential = new_contacts_credential->add_shared_credentials();
+        LOG(INFO) << __func__ << ": [Call Identity API] contacts_share";
+      }
+
+      shared_credential->set_id(
+          util_hash::HighwayFingerprint64(certificate.secret_id()));
+      shared_credential->set_data(certificate.SerializeAsString());
+      shared_credential->set_data_type(
+          ::google::nearby::identity::v1::SharedCredential::
+              DATA_TYPE_PUBLIC_CERTIFICATE);
+      *shared_credential->mutable_expiration_time() = certificate.end_time();
+      LOG(INFO) << __func__
+                << ": shared_credential.id(): " << shared_credential->id();
+    }
+    nearby_identity_client_->PublishDevice(
+        request, [this, callback = std::move(callback)](
+                     const absl::StatusOr<PublishDeviceResponse>& response) {
+          // check whether the manager is running again
+          if (!is_running()) {
+            LOG(WARNING)
+                << __func__
+                << ": [Call Identity API] manager is stopped after call.";
+            callback(/*success=*/false, /*contact_removed=*/false);
+            return;
+          }
+          if (!response.ok()) {
+            LOG(WARNING)
+                << __func__
+                << ": [Call Identity API] Failed to get response from backend: "
+                << response.status();
+            callback(/*success=*/false, /*contact_removed=*/false);
+            return;
+          }
+
+          LOG(INFO) << __func__
+                    << ": [Call Identity API] Successfully published device.";
+
+          // If contacts are removed, regenerate all Private certificates and
+          // make a 2nd PublishDevice RPC call.
+          bool need_another_call = false;
+          if (absl::linear_search(
+                  response.value().contact_updates().begin(),
+                  response.value().contact_updates().end(),
+                  google::nearby::identity::v1::PublishDeviceResponse::
+                      CONTACT_UPDATE_REMOVED)) {
+            need_another_call = true;
+            LOG(INFO)
+                << __func__
+                << ": [Call Identity API] need another PublishDevice call";
+          }
+          callback(/*success=*/true, /*contact_removed=*/need_another_call);
+        });
+  });
+}
 
 void NearbyShareLocalDeviceDataManagerImpl::UploadCertificates(
     std::vector<nearby::sharing::proto::PublicCertificate> certificates,
@@ -250,7 +356,6 @@ void NearbyShareLocalDeviceDataManagerImpl::UploadCertificates(
       callback(/*success=*/true);
       return;
     }
-
     UpdateDeviceRequest request;
     request.mutable_device()->set_name(
         absl::StrCat(kDeviceIdPrefix, device_id_));
diff --git a/sharing/local_device_data/nearby_share_local_device_data_manager_impl.h b/sharing/local_device_data/nearby_share_local_device_data_manager_impl.h
index 183ce270..7145f6ac 100644
--- a/sharing/local_device_data/nearby_share_local_device_data_manager_impl.h
+++ b/sharing/local_device_data/nearby_share_local_device_data_manager_impl.h
@@ -27,6 +27,7 @@
 #include "sharing/common/nearby_share_enums.h"
 #include "sharing/internal/api/preference_manager.h"
 #include "sharing/internal/api/sharing_rpc_client.h"
+#include "sharing/internal/impl/common/nearby_identity_grpc_client.h"
 #include "sharing/internal/public/context.h"
 #include "sharing/local_device_data/nearby_share_local_device_data_manager.h"
 #include "sharing/proto/rpc_resources.pb.h"
@@ -85,6 +86,10 @@ class NearbyShareLocalDeviceDataManagerImpl
       std::vector<nearby::sharing::proto::PublicCertificate> certificates,
       UploadCompleteCallback callback) override;
 
+  void PublishDevice(
+      std::vector<nearby::sharing::proto::PublicCertificate> certificates,
+      bool force_update_contacts, PublishDeviceCallback callback) override;
+
   // Creates a default device name of the form "<given name>'s <device type>."
   // For example, "Josh's Chromebook." If a given name cannot be found, returns
   // just the device type. If the resulting name is too long the user's name
@@ -95,6 +100,8 @@ class NearbyShareLocalDeviceDataManagerImpl
   AccountManager& account_manager_;
   nearby::DeviceInfo& device_info_;
   std::unique_ptr<nearby::sharing::api::SharingRpcClient> nearby_share_client_;
+  std::unique_ptr<nearby::sharing::api::IdentityRpcClient>
+      nearby_identity_client_;
   const std::string device_id_;
   std::unique_ptr<TaskRunner> executor_;
 };
diff --git a/sharing/local_device_data/nearby_share_local_device_data_manager_impl_test.cc b/sharing/local_device_data/nearby_share_local_device_data_manager_impl_test.cc
index 83005eab..c20d1b16 100644
--- a/sharing/local_device_data/nearby_share_local_device_data_manager_impl_test.cc
+++ b/sharing/local_device_data/nearby_share_local_device_data_manager_impl_test.cc
@@ -26,6 +26,7 @@
 #include "gtest/gtest.h"
 #include "absl/status/status.h"
 #include "absl/status/statusor.h"
+#include "absl/strings/str_cat.h"
 #include "absl/strings/substitute.h"
 #include "absl/time/time.h"
 #include "absl/types/optional.h"
@@ -33,14 +34,18 @@
 #include "internal/test/fake_account_manager.h"
 #include "internal/test/fake_device_info.h"
 #include "internal/test/fake_task_runner.h"
+#include "proto/identity/v1/resources.pb.h"
+#include "proto/identity/v1/rpcs.pb.h"
 #include "sharing/common/nearby_share_enums.h"
 #include "sharing/common/nearby_share_prefs.h"
 #include "sharing/internal/api/fake_nearby_share_client.h"
+#include "sharing/internal/public/logging.h"
 #include "sharing/internal/test/fake_context.h"
 #include "sharing/internal/test/fake_preference_manager.h"
 #include "sharing/local_device_data/nearby_share_local_device_data_manager.h"
 #include "sharing/proto/device_rpc.pb.h"
 #include "sharing/proto/rpc_resources.pb.h"
+#include "sharing/proto/timestamp.pb.h"
 #include "sharing/scheduling/fake_nearby_share_scheduler_factory.h"
 #include "sharing/scheduling/nearby_share_scheduler_factory.h"
 
@@ -49,6 +54,7 @@ namespace sharing {
 namespace {
 
 using UpdateDeviceResponse = nearby::sharing::proto::UpdateDeviceResponse;
+using google::nearby::identity::v1::PublishDeviceResponse;
 using Contact = nearby::sharing::proto::Contact;
 
 const char kDefaultDeviceName[] = "$0\'s $1";
@@ -232,6 +238,10 @@ class NearbyShareLocalDeviceDataManagerImplTest
     return nearby_client_factory_.instances().back();
   }
 
+  FakeNearbyIdentityClient* identity_client() {
+    return nearby_client_factory_.identity_instances().back();
+  }
+
   void Sync() {
     EXPECT_TRUE(context_.last_sequenced_task_runner()->SyncWithTimeout(
         absl::Milliseconds(1000)));
@@ -360,6 +370,183 @@ TEST_F(NearbyShareLocalDeviceDataManagerImplTest, UploadCertificates_Failure) {
   UploadCertificates(/*response=*/absl::InternalError(""));
 }
 
+std::vector<nearby::sharing::proto::PublicCertificate> GetTestCertificates() {
+  nearby::sharing::proto::PublicCertificate cert1;
+  cert1.set_secret_id("id1");
+  cert1.set_for_self_share(true);
+  cert1.mutable_end_time()->set_seconds(1000);
+  cert1.mutable_end_time()->set_nanos(2000);
+
+  nearby::sharing::proto::PublicCertificate cert2;
+  cert2.set_secret_id("id2");
+  cert2.set_for_self_share(false);
+  cert2.mutable_end_time()->set_seconds(2000);
+  cert2.mutable_end_time()->set_nanos(200);
+
+  nearby::sharing::proto::PublicCertificate cert3;
+  cert3.set_secret_id("id3");
+  cert3.set_for_self_share(true);
+  cert3.mutable_end_time()->set_seconds(3000);
+  cert3.mutable_end_time()->set_nanos(300);
+
+  nearby::sharing::proto::PublicCertificate cert4;
+  cert4.set_secret_id("id4");
+  cert4.set_for_self_share(false);
+  cert4.mutable_end_time()->set_seconds(4000);
+  cert4.mutable_end_time()->set_nanos(400);
+  return {cert1, cert2, cert3, cert4};
+}
+
+TEST_F(NearbyShareLocalDeviceDataManagerImplTest,
+       PublishDeviceInitialCall_ContactUpdateAdded) {
+  CreateManager();
+  bool returned_success;
+  bool returned_make_another_call;
+  PublishDeviceResponse response;
+  response.add_contact_updates(google::nearby::identity::v1::
+                                   PublishDeviceResponse::CONTACT_UPDATE_ADDED);
+
+  identity_client()->SetPublishDeviceResponse(
+      absl::StatusOr<PublishDeviceResponse>(response));
+  manager()->PublishDevice(GetTestCertificates(), /*is_second_call=*/false,
+                           [&returned_success, &returned_make_another_call](
+                               bool success, bool make_another_call) {
+                             returned_success = success;
+                             returned_make_another_call = make_another_call;
+                           });
+
+  Sync();
+  auto request = identity_client()->publish_device_requests().back();
+  EXPECT_EQ(request.device().name(),
+            absl::StrCat("devices/", manager()->GetId()));
+  EXPECT_EQ(request.device().display_name(), "Barack奥巴马's PC");
+  EXPECT_EQ(
+      request.device().contact(),
+      google::nearby::identity::v1::Device::CONTACT_GOOGLE_CONTACT_LATEST);
+  ASSERT_EQ(request.device().per_visibility_shared_credentials_size(), 2);
+
+  auto self_credential = request.device().per_visibility_shared_credentials(0);
+  EXPECT_EQ(self_credential.visibility(),
+            google::nearby::identity::v1::PerVisibilitySharedCredentials::
+                VISIBILITY_SELF);
+  EXPECT_EQ(self_credential.shared_credentials_size(), 2);
+  EXPECT_EQ(self_credential.shared_credentials(0).id(), 4993322223562966528);
+
+  ASSERT_EQ(GetTestCertificates().size(), 4);
+  EXPECT_EQ(self_credential.shared_credentials(0).data(),
+            GetTestCertificates().at(0).SerializeAsString());
+  EXPECT_EQ(self_credential.shared_credentials(0).data_type(),
+            google::nearby::identity::v1::SharedCredential::
+                DATA_TYPE_PUBLIC_CERTIFICATE);
+  EXPECT_EQ(self_credential.shared_credentials(0).expiration_time().seconds(),
+            1000);
+  EXPECT_EQ(self_credential.shared_credentials(0).expiration_time().nanos(),
+            2000);
+
+  EXPECT_EQ(self_credential.shared_credentials(1).id(), 2903692628687846585);
+  EXPECT_EQ(self_credential.shared_credentials(1).data(),
+            GetTestCertificates().at(2).SerializeAsString());
+  EXPECT_EQ(self_credential.shared_credentials(1).data_type(),
+            google::nearby::identity::v1::SharedCredential::
+                DATA_TYPE_PUBLIC_CERTIFICATE);
+  EXPECT_EQ(self_credential.shared_credentials(1).expiration_time().seconds(),
+            3000);
+  EXPECT_EQ(self_credential.shared_credentials(1).expiration_time().nanos(),
+            300);
+
+  auto contact_credential =
+      request.device().per_visibility_shared_credentials(1);
+  EXPECT_EQ(contact_credential.visibility(),
+            google::nearby::identity::v1::PerVisibilitySharedCredentials::
+                VISIBILITY_CONTACTS);
+  ASSERT_EQ(contact_credential.shared_credentials_size(), 2);
+  EXPECT_EQ(contact_credential.shared_credentials(0).id(),
+            -5684021477085783942);
+  EXPECT_EQ(contact_credential.shared_credentials(0).data(),
+            GetTestCertificates().at(1).SerializeAsString());
+  EXPECT_EQ(contact_credential.shared_credentials(0).data_type(),
+            google::nearby::identity::v1::SharedCredential::
+                DATA_TYPE_PUBLIC_CERTIFICATE);
+  EXPECT_EQ(
+      contact_credential.shared_credentials(0).expiration_time().seconds(),
+      2000);
+  EXPECT_EQ(contact_credential.shared_credentials(0).expiration_time().nanos(),
+            200);
+
+  EXPECT_TRUE(returned_success);
+  EXPECT_FALSE(returned_make_another_call);
+}
+
+TEST_F(NearbyShareLocalDeviceDataManagerImplTest,
+       PublishDeviceInitialCall_ContactUpdateRemoved) {
+  CreateManager();
+  bool returned_success;
+  bool returned_make_another_call;
+  PublishDeviceResponse response;
+  response.add_contact_updates(
+      google::nearby::identity::v1::PublishDeviceResponse::
+          CONTACT_UPDATE_REMOVED);
+
+  identity_client()->SetPublishDeviceResponse(
+      absl::StatusOr<PublishDeviceResponse>(response));
+  manager()->PublishDevice(GetTestCertificates(), /*is_second_call=*/false,
+                           [&returned_success, &returned_make_another_call](
+                               bool success, bool make_another_call) {
+                             returned_success = success;
+                             returned_make_another_call = make_another_call;
+                           });
+
+  Sync();
+
+  EXPECT_TRUE(returned_success);
+  // 2nd call is needed to regenerate all Private certificates.
+  EXPECT_TRUE(returned_make_another_call);
+}
+
+TEST_F(NearbyShareLocalDeviceDataManagerImplTest,
+       PublishDeviceSecondCall_ContactUnchanged) {
+  CreateManager();
+  bool returned_success;
+  bool returned_make_another_call;
+  PublishDeviceResponse response;
+
+  identity_client()->SetPublishDeviceResponse(
+      absl::StatusOr<PublishDeviceResponse>(response));
+  manager()->PublishDevice(GetTestCertificates(), /*is_second_call=*/true,
+                           [&returned_success, &returned_make_another_call](
+                               bool success, bool make_another_call) {
+                             returned_success = success;
+                             returned_make_another_call = make_another_call;
+                           });
+
+  Sync();
+  auto request = identity_client()->publish_device_requests().back();
+
+  EXPECT_EQ(request.device().contact(),
+            google::nearby::identity::v1::Device::CONTACT_GOOGLE_CONTACT);
+
+  EXPECT_TRUE(returned_success);
+  // Contacts are not changed, no need to make another call.
+  EXPECT_FALSE(returned_make_another_call);
+}
+
+TEST_F(NearbyShareLocalDeviceDataManagerImplTest, PublishDevice_Failure) {
+  CreateManager();
+  bool returned_success;
+  bool returned_make_another_call;
+  identity_client()->SetPublishDeviceResponse(absl::InternalError(""));
+  manager()->PublishDevice(GetTestCertificates(), /*is_second_call=*/false,
+                           [&returned_success, &returned_make_another_call](
+                               bool success, bool make_another_call) {
+                             returned_success = success;
+                             returned_make_another_call = make_another_call;
+                           });
+
+  Sync();
+  EXPECT_FALSE(returned_success);
+  EXPECT_FALSE(returned_make_another_call);
+}
+
 }  // namespace
 }  // namespace sharing
 }  // namespace nearby
diff --git a/sharing/nearby_sharing_service_impl.cc b/sharing/nearby_sharing_service_impl.cc
index 94270d5c..73d55a55 100644
--- a/sharing/nearby_sharing_service_impl.cc
+++ b/sharing/nearby_sharing_service_impl.cc
@@ -500,9 +500,10 @@ void NearbySharingServiceImpl::RegisterSendSurface(
         // user to be blocked for hours waiting for a periodic sync.
         if (state == SendSurfaceState::kForeground &&
             !last_outgoing_metadata_) {
-          VLOG(1) << __func__ << ": Downloading contacts & certificates from "
-                  << "Nearby server at start of sending flow.";
           contact_manager_->DownloadContacts();
+          VLOG(1) << __func__
+                  << ": Downloading public certificates from Nearby server at "
+                     "start of sending flow.";
           certificate_manager_->DownloadPublicCertificates();
         }
 
@@ -1030,9 +1031,10 @@ void NearbySharingServiceImpl::OnIncomingConnection(
   // need to wait for these calls to finish. The periodic server requests will
   // typically be sufficient, but we don't want the user to be blocked for
   // hours waiting for a periodic sync.
-  VLOG(1) << __func__ << ": Downloading contacts, and certificates from "
-          << "Nearby server at start of receiving flow.";
+
   contact_manager_->DownloadContacts();
+  VLOG(1) << __func__ << ": Downloading certificates from "
+          << "Nearby server at start of receiving flow.";
   certificate_manager_->DownloadPublicCertificates();
 
   ShareTarget placeholder_share_target;