  Expanding multi-country emissions trading system is considered as crucial to
fill the existing mitigation gap for the 2\degree C climate target. Trustworthy
emissions accounting is the cornerstone of such a system encompassing different
jurisdictions. However, traditional emissions measuring, reporting, and
verification practices that support data authenticity might not be applicable
as detailed data from large utilities and production facilities to be covered
in the multi-country emissions trading system are usually highly sensitive and
of severe national security concern. In this study, we propose a cryptographic
framework for an authenticated and secure emissions accounting system that can
resolve this data dilemma. We demonstrate that integrating a sequence of
cryptographic protocols can preserve data authenticity and security for a
stylized multi-country emissions trading system. We call for more research to
promote applications of modern cryptography in future international climate
governance to build trust and strengthen collaboration.
