The growth of world air traffic has been accompanied by a significant increase of its environmental impact, including CO2 emissions, which has forced the European Union to include aviation in its Emission Trading Scheme (EU ETS). The EU ETS is a market-based mechanism that obliges airlines to buy or sell carbon permits, thus forcing them to share confidential information with their competitors in an auction based market. Disclosure of confidential information will be one of the main barriers for the ETS adoption. In this contribution we describe the design and implementation of a Secure Multi-party Computation framework, capable of overcoming these barriers. The framework runs as an online, cloud-based computational service for performing CO2 trading securely without the need of sharing business information. Benefits and limitations of the proposed approach are discussed, as well as the challenges to be overcome towards an operational implementation. (C) 2016 Elsevier Ltd. All rights reserved.