Tech Tent 20: Making technology ethically

Tech firms are being asked to declare that their gadgets are made without the use of minerals whose sale could fund conflict in Africa. Should we believe their assurances? And, after another week of hacking attacks against well-known companies, is the use of passwords fundamentally flawed and is there a better alternative to their use?

Presenter Rory Cellan-Jones is joined by Dave Lee and Mark Ward from the BBC online technology desk, with special guest Ning Li, founder of the furniture e-commerce site Made.com