diff --git a/.github/workflows/validate.yaml b/.github/workflows/validate.yaml
index 25d7556e..2d03dcd2 100644
--- a/.github/workflows/validate.yaml
+++ b/.github/workflows/validate.yaml
@@ -37,6 +37,8 @@ jobs:
       run: CC=clang CXX=clang++ bazel build --check_visibility=false //connections:core --spawn_strategy=standalone
     - name: Build Presence
       run: CC=clang CXX=clang++ bazel build --check_visibility=false //presence --spawn_strategy=standalone
+    - name: Build Sharing
+      run: CC=clang CXX=clang++ bazel build --check_visibility=false //sharing/proto:all --spawn_strategy=standalone
 
   build-rust-linux:
     name: Build Rust on Linux
diff --git a/sharing/proto/BUILD b/sharing/proto/BUILD
new file mode 100644
index 00000000..c3a73631
--- /dev/null
+++ b/sharing/proto/BUILD
@@ -0,0 +1,35 @@
+load("@rules_cc//cc:defs.bzl", "cc_proto_library")
+
+licenses(["notice"])
+
+proto_library(
+    name = "share_proto",
+    srcs = [
+        "certificate_rpc.proto",
+        "contact_rpc.proto",
+        "device_rpc.proto",
+        "encrypted_metadata.proto",
+        "enums.proto",
+        "field_mask.proto",
+        "rpc_resources.proto",
+        "settings_observer_data.proto",
+        "timestamp.proto",
+        "wire_format.proto",
+    ],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//proto:sharing_enums_proto",
+    ],
+)
+
+proto_library(
+    name = "enums_proto",
+    srcs = ["enums.proto"],
+    visibility = ["//visibility:public"],
+)
+
+cc_proto_library(
+    name = "share_cc_proto",
+    visibility = ["//visibility:public"],
+    deps = [":share_proto"],
+)
diff --git a/sharing/proto/certificate_rpc.proto b/sharing/proto/certificate_rpc.proto
new file mode 100644
index 00000000..a57c8f15
--- /dev/null
+++ b/sharing/proto/certificate_rpc.proto
@@ -0,0 +1,53 @@
+// Copyright 2021 Google LLC
+//
+// 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
+//
+//     https://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.
+
+syntax = "proto3";
+
+package nearby.sharing.proto;
+
+import "sharing/proto/rpc_resources.proto";
+
+option optimize_for = LITE_RUNTIME;
+
+// Request to list public certificate objects.
+message ListPublicCertificatesRequest {
+  // Required. The resource name determines which public certificates to list.
+  // The special prefix "users/me" lists the requesters own share targets. This
+  // is of the format "users/*/devices/*".
+  string parent = 1;
+
+  // Optional limit on the number of ShareTarget objects to check for
+  // PublicCertificates for the response. Further PublicCertificates items may
+  // be obtained by including the page_token in a subsequent request. If this is
+  //  not set or zero, a reasonable default value is used.
+  int32 page_size = 2;
+
+  // Optional pagination token, returned earlier via
+  // [ListPublicCertificatesResponse.next_page_token]
+  string page_token = 3;
+
+  // Optional. Represents certificates already available on local device.
+  repeated bytes secret_ids = 4;
+}
+
+// Response that contains the public certificates available to calling device.
+message ListPublicCertificatesResponse {
+  // Optional. A token to retrieve the next page of results when used in
+  // [ListPublicCertificatesRequest].
+  string next_page_token = 1;
+
+  // Optional. Public certificates allowed to be accessed by the calling local
+  // device.
+  repeated PublicCertificate public_certificates = 2;
+}
diff --git a/sharing/proto/contact_rpc.proto b/sharing/proto/contact_rpc.proto
new file mode 100644
index 00000000..7f967534
--- /dev/null
+++ b/sharing/proto/contact_rpc.proto
@@ -0,0 +1,42 @@
+// Copyright 2021 Google LLC
+//
+// 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
+//
+//     https://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.
+
+syntax = "proto3";
+
+package nearby.sharing.proto;
+
+import "sharing/proto/rpc_resources.proto";
+
+option optimize_for = LITE_RUNTIME;
+
+// Request to list ContactRecord of a user.
+message ListContactPeopleRequest {
+  // Optional limit on the number of ContactRecord in
+  // [ListContactPeopleResponse.contact_records]. Defaults to 500 if not set.
+  int32 page_size = 1;
+
+  // Optional pagination token, returned earlier via
+  // [ListContactPeopleResponse.next_page_token]
+  string page_token = 2;
+}
+
+// Response from a ListContactPeopleRequest.
+message ListContactPeopleResponse {
+  // The ContactRecord in this collection.
+  repeated ContactRecord contact_records = 1;
+
+  // Optional. A token to retrieve the next page of results when used in
+  // [ListContactPeopleRequest]. Empty if no page is available.
+  string next_page_token = 2;
+}
diff --git a/sharing/proto/device_rpc.proto b/sharing/proto/device_rpc.proto
new file mode 100644
index 00000000..c92198a4
--- /dev/null
+++ b/sharing/proto/device_rpc.proto
@@ -0,0 +1,52 @@
+// Copyright 2021 Google LLC
+//
+// 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
+//
+//     https://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.
+
+syntax = "proto3";
+
+package nearby.sharing.proto;
+
+import "sharing/proto/field_mask.proto";
+import "sharing/proto/rpc_resources.proto";
+
+option optimize_for = LITE_RUNTIME;
+
+// The request used to register a [location.nearby.sharing.proto.Device]
+// with the server.
+message UpdateDeviceRequest {
+  // The [Device] to be updated.
+  Device device = 1;
+
+  // The FieldMask for updating specific columns in device table. For the
+  // 'FieldMask' definition, see
+  // https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#fieldmask
+  FieldMask update_mask = 2;
+}
+
+// The response for UpdateDeviceRequest.
+message UpdateDeviceResponse {
+  // The [Device] to be returned.
+  Device device = 1;
+
+  // Optional. The user's name as displayed to the user when selecting a share
+  // target. Ex: "Will Harmon"
+  string person_name = 2;
+
+  // Optional. The URL of an image displayed to the user when selecting a
+  // share target.
+  string image_url = 3;
+
+  // Optional. A hash like value to determine if the profile image has changed
+  // or not. Note, the image_url can change for the same image.
+  string image_token = 4;
+}
diff --git a/sharing/proto/encrypted_metadata.proto b/sharing/proto/encrypted_metadata.proto
new file mode 100644
index 00000000..af1342df
--- /dev/null
+++ b/sharing/proto/encrypted_metadata.proto
@@ -0,0 +1,47 @@
+// Copyright 2021 Google LLC
+//
+// 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
+//
+//     https://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.
+
+syntax = "proto2";
+
+package nearby.sharing.proto;
+
+option optimize_for = LITE_RUNTIME;
+
+// LINT.IfChange
+message EncryptedMetadata {
+  // The name of the local device when certificate is created.
+  optional string device_name = 1;
+
+  // The name of the user whose device created the certificate.
+  optional string full_name = 2;
+
+  // The icon url of the user whose device created the certificate.
+  optional string icon_url = 3;
+
+  // The Bluetooth MAC address of the device which created the certificate.
+  optional bytes bluetooth_mac_address = 4;
+
+  // The obfuscated Gaia ID of the account which created the certificate.
+  optional string obfuscated_gaia_id = 5;
+
+  // The name of the account which created the certificate.
+  optional string account_name = 6;
+
+  // The device's model name
+  optional string model_name = 7;
+
+  // The vendor ID of the local device.
+  optional int32 vendor_id = 8;
+}
+// LINT.ThenChange(//depot/google3/location/nearby/sharing/proto/contact_certificates.proto)
diff --git a/sharing/proto/enums.proto b/sharing/proto/enums.proto
new file mode 100644
index 00000000..d350febd
--- /dev/null
+++ b/sharing/proto/enums.proto
@@ -0,0 +1,61 @@
+// Copyright 2022 Google LLC
+//
+// 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
+//
+//     https://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.
+
+syntax = "proto3";
+
+package nearby.sharing.proto;
+
+option optimize_for = LITE_RUNTIME;
+
+// Represents the Fast Initiation Notification feature state. This feature
+// shows a notification when a nearby device is trying to share. It can be
+// enabled/disabled independently from the Nearby Share feature.
+enum FastInitiationNotificationState {
+  UNKNOWN_FAST_INIT = 0;
+  ENABLED_FAST_INIT = 1;
+  // User manually disabled the Fast Initiation Notification feature. If
+  // Nearby Share feature is toggled the notification feature will remain
+  // disabled.
+  DISABLED_BY_USER_FAST_INIT = 2;
+  // User turned off Nearby Share which disables the Fast Initiation
+  // Notification feature. If Nearby Share is enabled while Fast Initiation
+  // Notification is in this state then notifications will be re-enabled.
+  DISABLED_BY_FEATURE_FAST_INIT = 3;
+}
+
+enum DataUsage {
+  UNKNOWN_DATA_USAGE = 0;
+  // User is never willing to use the Internet
+  OFFLINE_DATA_USAGE = 1;
+  // User is always willing to use the Internet
+  ONLINE_DATA_USAGE = 2;
+  // User is willing to use the Internet on an un-metered connection.
+  // NOTE: This matches Android Nearby Share's naming for now.
+  WIFI_ONLY_DATA_USAGE = 3;
+}
+
+enum DeviceVisibility {
+  DEVICE_VISIBILITY_UNSPECIFIED = 0;
+  // The user is visible to no one.
+  DEVICE_VISIBILITY_HIDDEN = 1;
+  // The user is visible to devices signed in with the same account.
+  DEVICE_VISIBILITY_SELF_SHARE = 2;
+  // The user is visible to all contacts.
+  DEVICE_VISIBILITY_ALL_CONTACTS = 3;
+  // The user is visible to everyone.
+  DEVICE_VISIBILITY_EVERYONE = 4;
+  // TODO(b/251499089): Combine kAllContacts and kSelectedContacts to kContacts
+  // The user is only visible to selected contacts.
+  DEVICE_VISIBILITY_SELECTED_CONTACTS = 5;
+}
diff --git a/sharing/proto/field_mask.proto b/sharing/proto/field_mask.proto
new file mode 100644
index 00000000..375ebd77
--- /dev/null
+++ b/sharing/proto/field_mask.proto
@@ -0,0 +1,24 @@
+// Copyright 2021 Google LLC
+//
+// 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
+//
+//     https://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.
+
+syntax = "proto3";
+
+package nearby.sharing.proto;
+
+option optimize_for = LITE_RUNTIME;
+
+message FieldMask {
+  // The set of field mask paths.
+  repeated string paths = 1;
+}
diff --git a/sharing/proto/rpc_resources.proto b/sharing/proto/rpc_resources.proto
new file mode 100644
index 00000000..9efc96ae
--- /dev/null
+++ b/sharing/proto/rpc_resources.proto
@@ -0,0 +1,160 @@
+// Copyright 2021 Google LLC
+//
+// 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
+//
+//     https://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.
+
+syntax = "proto3";
+
+package nearby.sharing.proto;
+
+import "sharing/proto/timestamp.proto";
+
+option optimize_for = LITE_RUNTIME;
+
+// A SharedCertificate contains a secret key used when recognizing another
+// user's BLE advertisement and a public key used when establishing an encrypted
+// connection.
+//
+// How a Certificate is distributed is determined by who is on a user's contact
+// list. For example, if Will adds Ryan to his contact list, Ryan will have a
+// ShareTarget with Will's Certificate attached to it.
+// NextId=11
+message PublicCertificate {
+  // The secret (symmetric) identifier used when identifying the ShareTarget's
+  // BLE advertisement.
+  bytes secret_id = 1;
+
+  // The secret (symmetric) key is used to decrypt the name field of the
+  // ShareTarget's BLE advertisement.
+  bytes secret_key = 2;
+
+  // The public key is used to create a secure connection with the ShareTarget.
+  bytes public_key = 3;
+
+  // The time that certificate validity begins.
+  Timestamp start_time = 4;
+
+  // The time that certificate validity ends.
+  Timestamp end_time = 5;
+
+  // Indicates if this public certificate is only for selected contacts.
+  bool for_selected_contacts = 6;
+
+  // This aes key is uploaded from device to server, but not returned to device.
+  // It is only public to the server, for encrypting personal info metadata.
+  bytes metadata_encryption_key = 7;
+
+  // The encrypted metadata in bytes, contains personal information of the
+  // device/user who created this certificate. Needs to be decrypted into bytes,
+  // and converted back to EncryptedMetadata object to access fields.
+  // Definition of this object see:
+  // location/nearby/sharing/proto/contact_certificates.proto
+  bytes encrypted_metadata_bytes = 8;
+
+  // The tag for verifying metadata_encryption_key.
+  bytes metadata_encryption_key_tag = 9;
+
+  // Indicates if this public certificate corresponds to a device owned by the
+  // current user.
+  bool for_self_share = 10;
+}
+
+// A member of a contact list. This is not inlined on the recommendation of
+// http://go/apidosdonts##19-make-repeated-fields-messages-not-scalar-types
+// NextId=4
+message Contact {
+  // NextId=4
+  message Identifier {
+    oneof identifier {
+      string obfuscated_gaia = 1;
+      string phone_number = 2;
+      string account_name = 3;
+    }
+  }
+
+  // Required. The identifier of a contact can be an obfuscated gaia id, a phone
+  // number, or an email account name.
+  Identifier identifier = 1;
+
+  // Indicates if this contact is a selected contact.
+  bool is_selected = 2;
+
+  // Indicates if this contact is ourselves.
+  bool is_self = 3;
+}
+
+// A contact record from People backend.
+// NextId=7
+message ContactRecord {
+  // The type of the ContactRecord.
+  enum Type {
+    // The source of the contact is unknown.
+    UNKNOWN = 0;
+
+    // The source of the contact is from google (i.e. google.com/contacts).
+    GOOGLE_CONTACT = 1;
+
+    // The source of the contact is from a device.
+    DEVICE_CONTACT = 2;
+  }
+
+  // The stable id of this contact record.
+  string id = 1;
+
+  // The contact record's name.
+  string person_name = 2;
+
+  // The URL of an image displayed to the user when selecting a share
+  // target.
+  string image_url = 3;
+
+  // A list of phone numbers and emails under this contact record.
+  repeated Contact.Identifier identifiers = 4;
+
+  // The type of the ContactRecord.
+  Type type = 5;
+
+  // True if the contact record is WPS reachable.
+  bool is_reachable = 6;
+}
+
+// A ShareTarget is a potential destination of a share.
+// NextId=2
+message ShareTarget {
+  // Optional. Contains the keys required to identify and connect to this
+  // target.
+  repeated PublicCertificate public_certificates = 1;
+}
+
+// Consists of editable data inside of a device.
+// NextId=5
+message Device {
+  // Required. The resource name of this contact Device. This is of the format
+  // 'users/*/devices/*'. The special prefix 'users/me' uses the
+  // identity of the requester.
+  string name = 1;
+
+  // The device name to show members of this contact. Ex: "Joe's Pixel".
+  //
+  // NOTE: Do not use on Chrome. This appears to be an artifact of the old
+  // Nearby Share model, and could be a privacy risk that we want to avoid.
+  // The display name is instead included in the certificate encrypted metadata.
+  string display_name = 2;
+
+  // Users that this user has added to indicate that they may see this
+  // user as a ShareTarget when this user is nearby.
+  repeated Contact contacts = 3;
+
+  // The public certificates generated and uploaded from local device, to be
+  // shared with contacts.
+  repeated PublicCertificate public_certificates = 4;
+}
diff --git a/sharing/proto/settings_observer_data.proto b/sharing/proto/settings_observer_data.proto
new file mode 100644
index 00000000..1faddad8
--- /dev/null
+++ b/sharing/proto/settings_observer_data.proto
@@ -0,0 +1,42 @@
+// Copyright 2023 Google LLC
+//
+// 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
+//
+//     https://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.
+
+syntax = "proto3";
+
+package nearby.sharing.proto;
+
+option optimize_for = LITE_RUNTIME;
+
+// LINT.IfChange(TaggedUnion)
+// Tag and Data define a "variant" type, aka tagged union.
+// https://en.wikipedia.org/wiki/Tagged_union
+enum Tag {
+  TAG_NULL = 0;
+  TAG_BOOL = 1;
+  TAG_INT64 = 2;
+  TAG_STRING = 3;
+  TAG_STRING_ARRAY = 4;
+}
+
+message Data {
+  Tag tag = 1;
+  // Not using `oneof` because `repeated` is not allowed in `oneof`
+  optional bool as_bool = 2;
+  optional int64 as_int64 = 3;
+  optional string as_string = 4;
+  repeated string as_string_array = 5;
+}
+// LINT.ThenChange(
+//   //depot/google3/third_party/nearby/sharing/nearby_sharing_settings.h:TaggedUnion
+// )
diff --git a/sharing/proto/timestamp.proto b/sharing/proto/timestamp.proto
new file mode 100644
index 00000000..084dd570
--- /dev/null
+++ b/sharing/proto/timestamp.proto
@@ -0,0 +1,32 @@
+// Copyright 2021 Google LLC
+//
+// 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
+//
+//     https://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.
+
+syntax = "proto3";
+
+package nearby.sharing.proto;
+
+option optimize_for = LITE_RUNTIME;
+
+message Timestamp {
+  // Represents seconds of UTC time since Unix epoch
+  // 1970-01-01T00:00:00Z. Must be from 0001-01-01T00:00:00Z to
+  // 9999-12-31T23:59:59Z inclusive.
+  int64 seconds = 1;
+
+  // Non-negative fractions of a second at nanosecond resolution. Negative
+  // second values with fractions must still have non-negative nanos values
+  // that count forward in time. Must be from 0 to 999,999,999
+  // inclusive.
+  int32 nanos = 2;
+}
diff --git a/sharing/proto/wire_format.proto b/sharing/proto/wire_format.proto
new file mode 100644
index 00000000..111508ce
--- /dev/null
+++ b/sharing/proto/wire_format.proto
@@ -0,0 +1,339 @@
+syntax = "proto2";
+
+package nearby.sharing.service.proto;
+
+import "proto/sharing_enums.proto";
+
+option java_package = "com.google.android.gms.nearby.sharing";
+option java_outer_classname = "Protocol";
+option objc_class_prefix = "GNSHP";
+option optimize_for = LITE_RUNTIME;
+
+// File metadata. Does not include the actual bytes of the file.
+// NEXT_ID=6
+message FileMetadata {
+  enum Type {
+    UNKNOWN = 0;
+    IMAGE = 1;
+    VIDEO = 2;
+    ANDROID_APP = 3;
+    AUDIO = 4;
+    DOCUMENT = 5;
+  }
+
+  // The human readable name of this file (eg. 'Cookbook.pdf').
+  optional string name = 1;
+
+  // The type of file (eg. 'IMAGE' from 'dog.jpg'). Specifying a type helps
+  // provide a richer experience on the receiving side.
+  optional Type type = 2 [default = UNKNOWN];
+
+  // The FILE payload id that will be sent as a follow up containing the actual
+  // bytes of the file.
+  optional int64 payload_id = 3;
+
+  // The total size of the file.
+  optional int64 size = 4;
+
+  // The mimeType of file (eg. 'image/jpeg' from 'dog.jpg'). Specifying a
+  // mimeType helps provide a richer experience on receiving side.
+  optional string mime_type = 5 [default = "application/octet-stream"];
+
+  // A uuid for the attachment. Should be unique across all attachments.
+  optional int64 id = 6;
+
+  // The parent folder.
+  optional string parent_folder = 7;
+
+  // A stable identifier for the attachment. Used for receiver to identify same
+  // attachment from different transfers.
+  optional int64 attachment_hash = 8;
+}
+
+// NEXT_ID=5
+message TextMetadata {
+  enum Type {
+    UNKNOWN = 0;
+    TEXT = 1;
+    // Open with browsers.
+    URL = 2;
+    // Open with map apps.
+    ADDRESS = 3;
+    // Dial.
+    PHONE_NUMBER = 4;
+  }
+
+  // The title of the text content.
+  optional string text_title = 2;
+
+  // The type of text (phone number, url, address, or plain text).
+  optional Type type = 3 [default = UNKNOWN];
+
+  // The BYTE payload id that will be sent as a follow up containing the actual
+  // bytes of the text.
+  optional int64 payload_id = 4;
+
+  // The size of the text content.
+  optional int64 size = 5;
+
+  // A uuid for the attachment. Should be unique across all attachments.
+  optional int64 id = 6;
+}
+
+// NEXT_ID=5
+message WifiCredentialsMetadata {
+  enum SecurityType {
+    UNKNOWN_SECURITY_TYPE = 0;
+    OPEN = 1;
+    WPA_PSK = 2;
+    WEP = 3;
+    SAE = 4;
+  }
+
+  // The Wifi network name. This will be sent in introduction.
+  optional string ssid = 2;
+
+  // The security type of network (OPEN, WPA_PSK, WEP).
+  optional SecurityType security_type = 3 [default = UNKNOWN_SECURITY_TYPE];
+
+  // The BYTE payload id that will be sent as a follow up containing the
+  // password.
+  optional int64 payload_id = 4;
+
+  // A uuid for the attachment. Should be unique across all attachments.
+  optional int64 id = 5;
+}
+
+// NEXT_ID=8
+message AppMetadata {
+  // The app name. This will be sent in introduction.
+  optional string app_name = 1;
+
+  // The size of the all split of apks.
+  optional int64 size = 2;
+
+  // The File payload id that will be sent as a follow up containing the
+  // apk paths.
+  repeated int64 payload_id = 3 [packed = true];
+
+  // A uuid for the attachment. Should be unique across all attachments.
+  optional int64 id = 4;
+
+  // The name of apk file. This will be sent in introduction.
+  repeated string file_name = 5;
+
+  // The size of apk file. This will be sent in introduction.
+  repeated int64 file_size = 6 [packed = true];
+
+  // The package name. This will be sent in introduction.
+  optional string package_name = 7;
+}
+
+// A frame used when sending messages over the wire.
+// NEXT_ID=3
+message Frame {
+  enum Version {
+    UNKNOWN_VERSION = 0;
+    V1 = 1;
+  }
+  optional Version version = 1;
+
+  // Right now there's only 1 version, but if there are more, exactly one of
+  // the following fields will be set.
+  optional V1Frame v1 = 2;
+}
+
+// NEXT_ID=8
+message V1Frame {
+  enum FrameType {
+    UNKNOWN_FRAME_TYPE = 0;
+    INTRODUCTION = 1;
+    RESPONSE = 2;
+    PAIRED_KEY_ENCRYPTION = 3;
+    PAIRED_KEY_RESULT = 4;
+    CERTIFICATE_INFO = 5;
+    CANCEL = 6;
+    PROGRESS_UPDATE = 7;
+  }
+
+  optional FrameType type = 1;
+
+  // At most one of the following fields will be set.
+  optional IntroductionFrame introduction = 2;
+  optional ConnectionResponseFrame connection_response = 3;
+  optional PairedKeyEncryptionFrame paired_key_encryption = 4;
+  optional PairedKeyResultFrame paired_key_result = 5;
+  optional CertificateInfoFrame certificate_info = 6;
+  optional ProgressUpdateFrame progress_update = 7;
+}
+
+// An introduction packet sent by the sending side. Contains a list of files
+// they'd like to share.
+// NEXT_ID=7
+message IntroductionFrame {
+  repeated FileMetadata file_metadata = 1;
+  repeated TextMetadata text_metadata = 2;
+  // The required app package to open the content. May be null.
+  optional string required_package = 3;
+  repeated WifiCredentialsMetadata wifi_credentials_metadata = 4;
+  repeated AppMetadata app_metadata = 5;
+  optional bool start_transfer = 6;
+}
+
+// A progress update packet sent by the sending side. Contains transfer progress
+// value. NEXT_ID=3
+message ProgressUpdateFrame {
+  optional float progress = 1;
+
+  // True, if the receiver should start bandwidth upgrade and receiving the
+  // payloads.
+  optional bool start_transfer = 2;
+}
+
+// A response packet sent by the receiving side. Accepts or rejects the list of
+// files.
+// NEXT_ID=3
+message ConnectionResponseFrame {
+  enum Status {
+    UNKNOWN = 0;
+    ACCEPT = 1;
+    REJECT = 2;
+    NOT_ENOUGH_SPACE = 3;
+    UNSUPPORTED_ATTACHMENT_TYPE = 4;
+    TIMED_OUT = 5;
+  }
+
+  // The receiving side's response.
+  optional Status status = 1;
+
+  // Key is attachment hash, value is the details of attachment.
+  map<int64, AttachmentDetails> attachment_details = 2;
+}
+
+// Attachment details that sent in ConnectionResponseFrame.
+message AttachmentDetails {
+  // LINT.IfChange
+  enum Type {
+    UNKNOWN = 0;
+    // Represents FileAttachment.
+    FILE = 1;
+    // Represents TextAttachment.
+    TEXT = 2;
+    // Represents WifiCredentialsAttachment.
+    WIFI_CREDENTIALS = 3;
+    // Represents AppAttachment.
+    APP = 4;
+  }
+  // LINT.ThenChange(//depot/google3/java/com/google/android/gmscore/integ/client/nearby/src/com/google/android/gms/nearby/sharing/Attachment.java)
+
+  // The attachment family type.
+  optional Type type = 1;
+
+  // This field is only for FILE type.
+  optional FileAttachmentDetails file_attachment_details = 2;
+}
+
+// File attachment details included in ConnectionResponseFrame.
+message FileAttachmentDetails {
+  // Existing local file size on receiver side.
+  optional int64 receiver_existing_file_size = 1;
+
+  // The key is attachment hash, a stable identifier for the attachment.
+  // Value is list of payload details transferred for the attachment.
+  map<int64, PayloadsDetails> attachment_hash_payloads = 2;
+}
+
+message PayloadsDetails {
+  // The list should be sorted by creation timestamp.
+  repeated PayloadDetails payload_details = 1;
+}
+
+// Metadata of a payload file created by Nearby Connections.
+message PayloadDetails {
+  optional int64 id = 1;
+  optional int64 creation_timestamp_millis = 2;
+  optional int64 size = 3;
+}
+
+// A paired key encryption packet sent between devices, contains signed data.
+// NEXT_ID=5
+message PairedKeyEncryptionFrame {
+  // The encrypted data in byte array format.
+  optional bytes signed_data = 1;
+
+  // The hash of a certificate id.
+  optional bytes secret_id_hash = 2;
+
+  // An optional encrypted data in byte array format.
+  optional bytes optional_signed_data = 3;
+
+  // An optional QR code handshake data in a byte array format.
+  // For incoming connection contains a signature of the UKEY2
+  // token, created with the sender's private key.
+  // For outgoing connection contains an HKDF of the connection token and of the
+  // UKEY2 token
+  optional bytes qr_code_handshake_data = 4;
+}
+
+// A paired key verification result packet sent between devices.
+// NEXT_ID=3
+message PairedKeyResultFrame {
+  enum Status {
+    UNKNOWN = 0;
+    SUCCESS = 1;
+    FAIL = 2;
+    UNABLE = 3;
+  }
+
+  // The verification result.
+  optional Status status = 1;
+
+  // OS type.
+  optional location.nearby.proto.sharing.OSType os_type = 2;
+}
+
+// A package containing certificate info to be shared to remote device offline.
+// NEXT_ID=2
+message CertificateInfoFrame {
+  // The public certificates to be shared with remote devices.
+  repeated PublicCertificate public_certificate = 1;
+}
+
+// A public certificate from the local device.
+// NEXT_ID=8
+message PublicCertificate {
+  // The unique id of the public certificate.
+  optional bytes secret_id = 1;
+
+  // A bytes representation of a Secret Key owned by contact, to decrypt the
+  // metadata_key stored within the advertisement.
+  optional bytes authenticity_key = 2;
+
+  // A bytes representation a public key of X509Certificate, owned by contact,
+  // to decrypt encrypted UKEY2 (from Nearby Connections API) as a hand shake in
+  // contact verification phase.
+  optional bytes public_key = 3;
+
+  // The time in millis from epoch when this certificate becomes effective.
+  optional int64 start_time = 4;
+
+  // The time in millis from epoch when this certificate expires.
+  optional int64 end_time = 5;
+
+  // The encrypted metadata in bytes, contains personal information of the
+  // device/user who created this certificate. Needs to be decrypted into bytes,
+  // and converted back to EncryptedMetadata object to access fields.
+  optional bytes encrypted_metadata_bytes = 6;
+
+  // The tag for verifying metadata_encryption_key.
+  optional bytes metadata_encryption_key_tag = 7;
+}
+
+// NEXT_ID=3
+message WifiCredentials {
+  // Wi-Fi password.
+  optional string password = 1;
+  // True if the network is a hidden network that is not broadcasting its SSID.
+  // Default is false.
+  optional bool hidden_ssid = 2 [default = false];
+}