diff --git a/build.rs b/build.rs
index 725637b..2381388 100644
--- a/build.rs
+++ b/build.rs
@@ -34,6 +34,7 @@ static TARGETS: Lazy<HashMap<&str, Vec<&str>>> = Lazy::new(|| {
   m.insert(
     "models",
     vec![
+      "./proto/models/core/network.proto",
       "./proto/models/member/member_class.proto",
       "./proto/models/member/member_level.proto",
       "./proto/models/member/member_site.proto",
@@ -50,6 +51,8 @@ static TARGETS: Lazy<HashMap<&str, Vec<&str>>> = Lazy::new(|| {
     ],
   );
 
+  m.insert("ss", vec!["./proto/ss/member/identity.proto"]);
+
   m
 });
 
diff --git a/proto/c2se/backend/identity.proto b/proto/c2se/backend/identity.proto
index d54d7f5..a2345bd 100644
--- a/proto/c2se/backend/identity.proto
+++ b/proto/c2se/backend/identity.proto
@@ -4,6 +4,15 @@ package bet.beteran.c2se.backend.identity;
 
 import "protobuf/rpc/error.proto";
 
+// subject = bet.beteran.c2se.backend.identity.Captcha
+message CaptchaRequest {
+}
+
+message CaptchaResponse {
+  optional bet.protobuf.rpc.Error error = 1;
+  optional string image = 2;
+}
+
 // subject = bet.beteran.c2se.backend.identity.Signin
 message SigninRequest {
   string username = 1;
@@ -15,3 +24,4 @@ message SigninResponse {
   optional bet.protobuf.rpc.Error error = 1;
   optional string token = 2;
 }
+
diff --git a/proto/c2se/core/network.proto b/proto/c2se/core/network.proto
new file mode 100644
index 0000000..c6146c2
--- /dev/null
+++ b/proto/c2se/core/network.proto
@@ -0,0 +1 @@
+// header = bet.beteran.c2se.core.network.Client
diff --git a/proto/c2se/frontend/identity.proto b/proto/c2se/frontend/identity.proto
index 8c4d427..746313b 100644
--- a/proto/c2se/frontend/identity.proto
+++ b/proto/c2se/frontend/identity.proto
@@ -4,6 +4,15 @@ package bet.beteran.c2se.frontend.identity;
 
 import "protobuf/rpc/error.proto";
 
+// subject = bet.beteran.c2se.frontend.identity.Captcha
+message CaptchaRequest {
+}
+
+message CaptchaResponse {
+  optional bet.protobuf.rpc.Error error = 1;
+  optional string image = 2;
+}
+
 // subject = bet.beteran.c2se.frontend.identity.Signin
 message SigninRequest {
   string username = 1;
diff --git a/proto/models/core/network.proto b/proto/models/core/network.proto
new file mode 100644
index 0000000..7e17c58
--- /dev/null
+++ b/proto/models/core/network.proto
@@ -0,0 +1,9 @@
+syntax = "proto3";
+
+package bet.beteran.core.network;
+
+message Client {
+  optional string site_url = 1;
+  uint64 client_id = 2;
+  string client_ip = 3;
+}
diff --git a/proto/ss/member/identity.proto b/proto/ss/member/identity.proto
new file mode 100644
index 0000000..9c99677
--- /dev/null
+++ b/proto/ss/member/identity.proto
@@ -0,0 +1,30 @@
+syntax = "proto3";
+
+package bet.beteran.ss.member.identity;
+
+import "protobuf/rpc/error.proto";
+import "models/core/network.proto";
+
+// subject = bet.beteran.ss.member.identity.Captcha
+message CaptchaRequest {
+  bet.beteran.core.network.Client client = 1;
+}
+
+message CaptchaResponse {
+  optional bet.protobuf.rpc.Error error = 1;
+  optional string image = 2;
+}
+
+
+// subject = bet.beteran.ss.member.identity.Signin
+message SigninRequest {
+  bet.beteran.core.network.Client client = 1;
+  string username = 2;
+  string password = 3;
+  string security_code = 4;
+}
+
+message SigninResponse {
+  optional bet.protobuf.rpc.Error error = 1;
+  optional string token = 2;
+}