Hacker News on 13 November 2021

• Sign arbitrary data with your SSH keys
• Restic – Backups Done Right
• Email from FBI Looks Odd
• Hoax email blast abused poor coding in FBI website
• Reverse-engineering the Yamaha DX7 synthesizer's sound chip from die photos
• The case of the 500-mile email (2002)
• Project Euler
• Higher Math for Beginners (1987)
• Debit cards are hidden financial infrastructure
• Richard ‘Lowtax’ Kyanka, founder of Something Awful, has died