Usable security + Visual design ECE 695 Alexander J. Quinn 4/6/2016

Usable security – finish up Today Usable security – finish up Examples of poor usability  poor security Passwords More tips Visual design Font metrics Gestalt Discuss

Usable security failures If the 3rd to last digit of your PUID or SSN is… ODD  think of the worst instance of unusable security you’ve ever seen. EVEN  think of one that is fake, but might sound real. Try to fool people. Give a 30- to 60-second rant on why it is bad. We’ll vote and see how well we can guess.

Passwords

What matters? Benefit Cost Entropy Cost What is cost? keystrokes? mental “chunks”?

What do you think? Fingerprints Face recognition Voice Retina SecureID Two-factor

Multiple lines of defense Limit cognitive/memory demands More guidelines Usability overall Security overall Multiple lines of defense Limit cognitive/memory demands Present syntactic information in ways attackers can’t manipulate Expose potential anomalies Avoid false senses of security Consistency http://www.cc.gatech.edu/~keith/pubs/ieee-intro-usable-security.pdf

Visual design

Font metrics Credit: Ivo Vynckier, http://www.how-ocr-works.com/images/resolution.html

Typography in CSS font-family font-size font-weight font-style font-variant font letter-spacing word-spacing line-height text-align text-decoration text-indent text-transform text-shadow vertical-align white-space direction unicode-bidi

Typography in CSS em ex ch rem Relative to viewport vh vw vmin vmax Relative to text em ex ch rem Relative to viewport vh vw vmin vmax Absolute px mm cm in pt pc mozmm

20 Examples of Beautiful CSS Typography Design https://wdexplorer.com/20-examples-beautiful-css-typography-design/ 20 Examples of Beautiful CSS Typography Design

Gestalt: Similarity

Gestalt: Reification

Gestalt: Multistability

Gestalt: Invariance

Gestalt: Closure