diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index d619d80..46c071b 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -28,6 +28,7 @@
 #include "ssl_misc.h"
 #include <mbedtls/debug.h>
 
+/* Main entry point; orchestrates the other functions */
 static int ssl_client_hello_process( mbedtls_ssl_context* ssl );
 
 int mbedtls_ssl_handshake_client_step_tls1_3( mbedtls_ssl_context *ssl )
@@ -66,20 +67,73 @@
     return( ret );
 }
 
+
+static int ssl_client_hello_prepare( mbedtls_ssl_context* ssl );
+static int ssl_client_hello_write_partial( mbedtls_ssl_context* ssl,
+                                           unsigned char* buf, size_t buflen,
+                                           size_t* len_without_binders,
+                                           size_t* len_with_binders );
+static int ssl_client_hello_postprocess( mbedtls_ssl_context* ssl );
+
 static int ssl_client_hello_process( mbedtls_ssl_context* ssl )
 {
     int ret = 0;
+    unsigned char *buf;
+    size_t buf_len, msg_len;
+    size_t len_without_binders = 0;
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write client hello" ) );
 
+    MBEDTLS_SSL_PROC_CHK( ssl_client_hello_prepare, ( ssl ) );
+
+    MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg, ( ssl,
+                 MBEDTLS_SSL_HS_CLIENT_HELLO, &buf, &buf_len ) );
+
+    MBEDTLS_SSL_PROC_CHK( ssl_client_hello_write_partial, ( ssl, buf, buf_len,
+                                                  &len_without_binders,
+                                                  &msg_len ) );
+
+    mbedtls_ssl_add_hs_hdr_to_checksum( ssl, MBEDTLS_SSL_HS_CLIENT_HELLO,
+                                        msg_len );
+    ssl->handshake->update_checksum( ssl, buf, len_without_binders );
+
+    MBEDTLS_SSL_PROC_CHK( ssl_client_hello_postprocess, ( ssl ) );
+    MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg, ( ssl, buf_len, msg_len ) );
     mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_HELLO );
 
+cleanup:
+
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write client hello" ) );
     /* client_hello_process haven't finished */
     ret=MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
     return ret;
 }
 
+static int ssl_client_hello_prepare( mbedtls_ssl_context* ssl )
+{
+    ((void) ssl);
+    return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
+}
+
+static int ssl_client_hello_write_partial( mbedtls_ssl_context* ssl,
+                                           unsigned char* buf, size_t buflen,
+                                           size_t* len_without_binders,
+                                           size_t* len_with_binders )
+{
+    ((void) ssl);
+    ((void) buf);
+    ((void) buflen);
+    ((void) len_without_binders);
+    ((void) len_with_binders);
+    return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
+}
+
+static int ssl_client_hello_postprocess( mbedtls_ssl_context* ssl )
+{
+    ((void) ssl);
+    return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
+}
+
 #endif /* MBEDTLS_SSL_CLI_C */
 
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */