Casual Privacy

“a design pattern for sharing non-public information using out-of-band exchange of unguessable tokens.”

because most privacy isn’t worth it.

Privacy is more trouble then its worth right now. Some people share in public, some people give up.

How to do we get more people to share more information, and more interesting information?

Is there information you’re sharing more widely right now then you feel comfortable with?

Is there information you’d share with more people if it was easy that you don’t want to tell GoogleBot?

Assertion:

Open Questions:

Current Privacy Options

1. Share Nothing

2. Share Everything

3. Manage a crowd

Everything Private Sucks

• Lonely!

• No wisdom of the crowds

• Web 1.0!

• We’d all be out of jobs!

Share Everything?

On Flickr people want to share (privately)

1. Kids

2. Home

3. Weddings

4. Last nights party

• Default Web 2.0 assumption (Flickr, del.icio.us, Upcoming, Twitter)

• Not everyone can, will

Sharing: Because it works!

• Outboard brain

• Wisdom of crowds

• Serendipity enhancement

• More valuable then privacy?

friend, family, contact, acquaintance, met, co-worker, colleague, co-resident, neighbor, child, parent, sibling, spouse, kin, muse, crush, date, sweetheart, me, friend, family, contact, acquaintance, met, co-worker, colleague, co-resident, neighbor, child, parent, sibling, spouse, kin, muse, crush, date, sweetheart, me, friend, family, contact, acquaintance, met, co-worker, colleague, co-resident, neighbor, child, parent, sibling, spouse, kin, muse, crush, date, sweetheart, me, friend, family, contact, acquaintance, met, co-worker, colleague, co-resident, neighbor, child, parent, sibling, spouse, kin, muse, crush, date, sweetheart, me, acquaintance, met, co-worker, colleague, co-resident, neighbor, child, parent, sibling, spouse, kin, muse, crush, date, sweetheart, me, friend, family, contact, quasi-friend, sort-a-friend, weird-uncle, kith, annoying ex-roomate

Manage a crowd

• “Traditional” approach• Contacts + Roles• Complex• Cognitive burden• also: ego, anxiety, social pressure, attractive

nuisance.

Account proliferation!

• Contact based approach, everyone needs an account.

• Use ~14 sites roughly daily all designed to share.

• Small pieces loosely joined hurts now

“a design pattern for sharing non-public information using out-of-band exchange of unguessable tokens.”

http://flickr.com/gp/86712998@N00/BWk63T

SUPER SEKRET URLZ!!1!

Case Study: Flickr Guest Pass

http://flickr.com/gp/ + 86712998@N00/ + BWk63Tj7

Simple?• No authentication• No account need• No activation• No identity• You have the token, you're in.

Casual Privacy: Features

• Its Internet scale by default!

• Credential are forwardable.

• Authorization is contextual

OMG Alice isn't trustworthy and leaked the secret token!

• In practice, accidental not malicious

• Tokens revokable. Always. Poof!

• Visual cues

• Sufficient information

Deniable

• Don't leak

• No sequential IDs

• No hinting

• Don’t bring the egos back

• Greenfield: “beneficial hypocrisy”

Hard to Guess

• 8 places of random alpha-numerics gets you a really big search spaces

• 2,251,875,390,625

• Extra fun? Make your tokens checksumable

History Of

• Odeo, 2005

• Quicktopic, 1999

• High school rave, 1992

Worse is Better

• More flexible

• Network effects make databases cry

• Everybody less anxious

Casual Privacy: Checklist

• Simple

• Forwardable/sharedable

• Revokable

• Deniable

• Visual Indicators

• Hard to guess

• Easy to implement

Security Concerns

• Don’t use in feeds (aggregator data hygiene sucks!)

• Proxies cache URL. HTTP headers can help

• document.location.hash

Future Work

• Data fuzzing

• URL decay

• Ben Adida’s BeamAuth

• Build it already!

• http://flickr.com/photos/dirtyfeet/217931104/• http://flickr.com/photos/lalunablanca/62556584/• http://flickr.com/photos/mesolimbo/86561068/• http://flickr.com/photos/merlin/13374753/• http://flickr.com/photos/fetching/387574792/• http://flickr.com/photos/stewart/459153074/• http://flickr.com/photos/oybay/111504290/• http://flickr.com/photos/

68888883@N00/274651759/• http://flickr.com/photos/laughingsquid/

390813713/ - Scott Beale / Laughing Squid (laughingsquid.com)