Knock, Knock. Who’s There? On the Security of LG’s Knock Codes
summary
Knock Codes on LG phones are studied with 351 mobile participants who create 1,138 codes and a derived blocklist of 30 codes; estimated deployment is 700,000–2,500,000 users in the US. A 2x3 grid adds options but not security; many codes start upper-left and are predictable so a perfect-knowledge attacker cracks >50% cracked within 30 guesses. Blocklisting raises work by about 1.5 bits but usability is poor: median entry ~7 seconds and recall failures of ~1/8 and ~1/5 across treatments.
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chapters (15)
- 0:00Intro
- 0:37HOW DO YOU UNLOCK YOUR PHONE?
- 1:17LG KNOCK CODES: A DIFFERENT WAY TO UNLOCK
- 2:39APPROACH
- 3:46TREATMENTS
- 4:19KNOWLEDGE BASED AUTHENTICATION USAGE
- 5:08STUDY DESIGN
- 5:47TOP 3 KNOCK CODES: CONTROL
- 6:36TOP 3 KNOCK CODES: LARGE
- 6:57KNOCK CODE START/END FREQUENCY
- 7:39SECURITY ANALYSIS: THREAT MODELS
- 8:47SECURITY ANALYSIS: PERFECT KNOWLEDGE ATTACKER
- 9:50SIMULATED ATTACKER
- 11:50USABILITY ANALYSIS: User Responses
- 12:18CONCLUSION
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