Cardea is a fully open-source and field-tested verifiable digital credential that meets the major requirements of the Good Health Pass.

With the rollout of the EU Digital COVID Certificate (previously called the Digital Green
Certificate), digital health credentials for managing COVID-19 are now a reality. Political urgency has, unsurprisingly, driven the certificate’s development. A borderless political bloc needs a safe way to ensure travel within its member states. The question is how to make these certificates work—and evolve—in a way that maximizes privacy and security, while interoperating with other credential systems outside the EU.

Linux Foundation Public Health (LFPH) is leading two collaborative projects that aim to do this. The Global COVID Certificate Network, announced today, is a way for COVID-19 test certificates issued in one country to be recognized as authoritative in another. The second is the Good Health Pass Collaborative, an industry coalition that has defined principles and standards for COVID-19 certificates themselves so that they are privacy-preserving, secure, and interoperable. The Good Health Pass “blueprint” is currently in public draft review.

Cardea, a full, open-source ecosystem for verifiable health credentials developed by Indicio and now a community-led project at LFPH, meets the major recommendations of the Good Health Pass and facilitates the goals of the Global COVID Certificate Network.

The chart below shows the alignment between Cardea and the Good Health Pass recommendations—and where development efforts will be focused to enable full compliance.

The Good Health Pass recommendations and Cardea at-a-glance

Cardea has been successfully trialed on the island of Aruba by SITA, the leading global provider of technology to the air transport industry. The pilot project enabled travelers to prove their Covid-test status to restaurants and hospitality locations around the island without having to share any personal information. Dangui Oduber, Aruba’s minister of tourism, public health and sport, described the ability to trust important health information while preserving visitors’ privacy as “a revolutionary step forward.”

Cardea’s strength as a functioning, deployable ecosystem is that it is built using open source software and doesn’t require any proprietary technology for implementation. It is based on the Hyperledger Indy platform, and uses Hyperledger Aries agents and Hyperledger Ursa cryptography—each backed by dynamic developer communities.

The Cardea Community Group, which meets weekly, is led by co-chairs, Ken Ebert, CTO of Indicio, and Keela Shatzkin of Shatzkin Systems. The Cardea Steering Committee, which will guide Cardea’s development  is currently composed of Trevor Butterworth, Indicio; Kristy Gale, Honor DRM; John Kindervag, ON2IT; RJ Reiser, Liquid Avatar;  Adrien Sanglier, SITA; Mitja Simcic, GlobaliD, and Mike Vesey, IdRamp. The Cardea Steering Committee is committed to inclusion in developing this project and will actively engage in recruiting a diversity of voices to join the committee.

To learn more or get involved in the growing Cardea Community, go to or Linux Foundation Public Health, or contact us at Indicio.