ETSI TS103457 "Trusted Cross-Domain Interface: Interface to offload sensitive functions to a trusted domain"

Example implementation and demonstrator

This software is made of a library providing connection and session with trust management, message encoding and related functionnal examples done at server side (MTD).

Dependencies installation

This description is for debian linux distribution.

Build tool packages :

• g++
• cmake

For botan library

• libboost-all-dev
• lzma-dev
• liblzma-dev
• libbz2-dev
• libssl-dev
• xv-utils

For documentation :

• doxygen
• graphviz

For client GUI :

• python3
• python3-pip
• python3-tk

Libraries from github are required:

• botan (crypto library): https://github.com/randombit/botan (version 2.17.3)
• spdlog (logging library): https://github.com/gabime/spdlog
• google catch2 (unit testing framework): https://github.com/catchorg/Catch2 (version v2.13.4)

botan build

• from source project root
• ./configure.py --with-boost --with-openssl --with-bzip2 --with-lzma --with-zlib
• make

spdlog build

• mkdir build && cd buid && cmake ..
• make

The location of the dependency libraries is defined in main CMakeLists.txt Default locations are ../botan-git, ../spdlog-git and ../Catch2-git

Project build

The library is C++ coded and uses cmake toolchain for building The build generates libetsi103457 library, example MTD server, doxygen documentation and unit testing binaries.

These build options can be used with cmake:

• -DETSI103457_BUILD_TESTS=1 to enable unit testing

• -DETSI103457_BUILD_EXAMPLE=1 to build the server

Code description

Every function from the TS has a corresponding class derived from a TDS_Commands base class. The concept elements defined in TS are directly mapped into classes in the library :

• TD_Message is the TTLV encoded command/response content
• TD_Object is the generic object handled by the MTD
• TD_Container is a MTD container

TD_TLLVTools is a static class used for coding/decoding all the types defined in the standard TD_Connection is in charge of the protocol connection handling over and except the transport layer. TD_Session_Manager is for the lifecycle management of the objects inside the sessions.

Demonstrator description

The project goal is to illustrate the interactions and processings for the two domains, MTD, the more trusted domain and LTD, the lesser one. It exhibits a client/server architecture where the client in LTD offload some sensible processings to an MTD server.

A TLS transport layer is used as recommended in standard. Demo keys and certificates are given in pki directory.

The client is a pure python implementation with a portable Tk GUI.

Demonstrator Usage

From example directory

• The client can be run with python3 etsi103457-gui.py
• The server can be run with ./tls_server.sh wrapper script

Demonstrator limitations

• The Demonstrator server is synchronous and will only accept a single client connection at a time
• DB access has not been implemented in this Demonstrator, therefore (key/value) base type are not supported
• TD_OpenConnection :
  • parameters are not used
• TD_TrustRenewal :
  • Trust is automatically checked every 240 seconds from the client. In order to demonstrate the loss of trust, BAD_CN is passed to the server as CN value when the Trusted Value checkbox is unticked in the client
• TD_Object :
  • Allthough Objects are stored as RAW data (bytestrings), Object values should be entered as string for logging purpose
• TD_GetRandom :
  • SizeInBytes shall be lower than XX due to libbotan implementation
• Archive and Storage are stored as files by default in /tmp and are prefixed by ARC and STO for demonstration purposes
  • Files content is stored as human readable content. The Storage name is stored as a string when applying, Object_Id are stored as human readable uuid, and values are Base64 encoded