The former National Security Agency contractor who exposed US government surveillance programmes by disclosing classified material in 2013 has a new job: app developer.

Edward Snowden in a video message on Friday unveiled a new phone app he helped create, called Haven, that aims to protect laptops from physical tampering.

Snowden says it is an open-source tool designed for human rights activists and other people at risk and it uses an Android phone’s sensors to detect changes in a room.

The software was developed with the Freedom of Press Foundation and The Guardian Project. It has been greeted with mixed social media reactions, with some people celebrating its security capabilities and others saying they don’t trust Snowden.