diff --git a/src/curve_server.cpp b/src/curve_server.cpp
index 4255fa2f..7d0d730c 100644
--- a/src/curve_server.cpp
+++ b/src/curve_server.cpp
@@ -537,6 +537,14 @@ void zmq::curve_server_t::send_zap_request (const uint8_t *key)
     rc = session->write_zap_msg (&msg);
     errno_assert (rc == 0);
 
+    // identity frame 
+    rc = msg.init_size (options.identity_size);
+    errno_assert(rc == 0);
+    memcpy (msg.data (), options.identity, options.identity_size);
+    msg.set_flags (msg_t::more);
+    rc = session->write_zap_msg (&msg);
+    errno_assert (rc == 0);
+
     //  Mechanism frame
     rc = msg.init_size (5);
     errno_assert (rc == 0);
diff --git a/src/plain_mechanism.cpp b/src/plain_mechanism.cpp
index 8090909b..85173ffa 100644
--- a/src/plain_mechanism.cpp
+++ b/src/plain_mechanism.cpp
@@ -380,6 +380,14 @@ void zmq::plain_mechanism_t::send_zap_request (const std::string &username,
     rc = session->write_zap_msg (&msg);
     errno_assert (rc == 0);
 
+    // identity frame 
+    rc = msg.init_size (options.identity_size);
+    errno_assert(rc == 0);
+    memcpy (msg.data (), options.identity, options.identity_size);
+    msg.set_flags (msg_t::more);
+    rc = session->write_zap_msg (&msg);
+    errno_assert (rc == 0);
+
     //  Mechanism frame
     rc = msg.init_size (5);
     errno_assert (rc == 0);
diff --git a/tests/test_security.cpp b/tests/test_security.cpp
index e6feed34..29907c47 100644
--- a/tests/test_security.cpp
+++ b/tests/test_security.cpp
@@ -28,12 +28,15 @@ static void zap_handler (void *zap)
     char *sequence = s_recv (zap);
     char *domain = s_recv (zap);
     char *address = s_recv (zap);
+    char *identity = s_recv(zap);
     char *mechanism = s_recv (zap);
     char *username = s_recv (zap);
     char *password = s_recv (zap);
     
+    printf("identity: %s\n", identity);
     assert (streq (version, "1.0"));
     assert (streq (mechanism, "PLAIN"));
+    assert (streq (identity, "IDENT"));
 
     s_sendmore (zap, version);
     s_sendmore (zap, sequence);
@@ -55,6 +58,7 @@ static void zap_handler (void *zap)
     free (sequence);
     free (domain);
     free (address);
+    free (identity);
     free (mechanism);
     free (username);
     free (password);
@@ -115,6 +119,7 @@ int main (void)
     //  Check PLAIN security
     server = zmq_socket (ctx, ZMQ_DEALER);
     assert (server);
+    rc = zmq_setsockopt(server, ZMQ_IDENTITY, "IDENT",6);
     client = zmq_socket (ctx, ZMQ_DEALER);
     assert (client);
     
diff --git a/tests/test_security_curve.cpp b/tests/test_security_curve.cpp
index 19304c12..7804526c 100644
--- a/tests/test_security_curve.cpp
+++ b/tests/test_security_curve.cpp
@@ -29,11 +29,13 @@ static void zap_handler (void *zap)
     char *sequence = s_recv (zap);
     char *domain = s_recv (zap);
     char *address = s_recv (zap);
+    char *identity = s_recv(zap);
     char *mechanism = s_recv (zap);
     char *client_key = s_recv (zap);
     
     assert (streq (version, "1.0"));
     assert (streq (mechanism, "CURVE"));
+    assert (streq (identity, "IDENT"));
 
     s_sendmore (zap, version);
     s_sendmore (zap, sequence);
@@ -46,6 +48,7 @@ static void zap_handler (void *zap)
     free (sequence);
     free (domain);
     free (address);
+    free (identity);
     free (mechanism);
     free (client_key);
     
@@ -87,6 +90,8 @@ int main (void)
     assert (rc == 0);
     rc = zmq_setsockopt (server, ZMQ_CURVE_SECRETKEY, server_secret, 40);
     assert (rc == 0);
+    rc = zmq_setsockopt(server, ZMQ_IDENTITY, "IDENT",6);
+    assert (rc == 0);
 
     rc = zmq_setsockopt (client, ZMQ_CURVE_SERVERKEY, server_public, 40);
     assert (rc == 0);