Lenovo sold thousands of computers all carrying the Superfish software. Tom Scott explains what a security nightmare this became. More Tom Scott: CORRECTION: At 2min 46secs Tom says "Private Key" when he means "Public Key" - The private key is not shared. Chip & PIN Fraud: Could We Ban Encryption?: How Blurs & Filters work: Numberphile: Encryption & Huge Numbers : Public Key Cryptography: This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: Computerphile is a sister project to Brady Haran's Numberphile. More at