1. Monica Lam Stanford University with Dan Boneh, Ruven Chu, Ben Dodson, Bobby Georgescu, Sudheendra Hangal, Te-Yuan Huang, Diana MacLean, Chanh Nguyen, Debangsu Sengupta, Jiwon Seo, Seok-Won Seong, Chinmay Soman, Steven Soneff, Seng Keat Teh, Ian Vo Datalog for Decentralized Social Networking Part of POMI (Programmable Open Mobile Internet 2020), an NSF Expedition

2. Outline Why decentralized social networking? Overall architecture Datalog Access control

3. Trends in Social Networking

4. The Omniscient Monopoly

5. Sooner Than You Think

6. It’s the Technologists’ Fault There is no easy alternative to share!

7. Big-Brother Portals Flicker Portal Email Portal Web Browser Web Browser Facebook Portal Poker Portal Poker Portal Web Browser Web Browser Web Browser Web Browser Loss of independence / Competition Scalability Data privacy Data silos

8. Big-Brother Portals Flicker Portal Email Portal Web Browser Web Browser Facebook Portal Poker Portal Poker Portal Web Browser Web Browser Web Browser Web Browser

9. Approach Decentralized architecture Scalability, independence, privacy Much more powerful than centralized Open API for collaboration

10. Data is What’s Important Personal Cloud Butler: Mediates access to personal data Manages a semantic index pointing to data hosted anywhere The index can’t be encrypted My Personal Cloud GPS Trace Credit card history Email Phone record Friends’ List Calendar

11. Where is the Butler? Where data are consumed. Tera-bytes of personal data! Person-Cloud Butlers 32 GB instantaneously. With you all the time, Even when not connected. Private. Better than the cloud!

12. Phone: Digital Identity, Wallet Unique password. for each website Login in 5 seconds Challenge Response Authentication

13. Phone: Digital Personality WeTube: Ad hoc sharing without an ASP

14. weBluff... Accept with a snap Download software Join activity Start Activity Invite: QR code 408-555-5555 ACCEPT Verifiably fair [Blum 82]

15. Concepts in Decentralization Phone as your digital identity Junction: a decentralized platform for ad hoc, social applications

16. PrPl: Private-Public Data Infrastructure Flicker Portal Email Portal Web Browser Web Browser Facebook Portal Personal- Cloud Butler Web Browser Web Browser Millions of Personal Terabyte Databases Out There!

17. Personal-Cloud Butler Social Multi-Database PrPl Index OpenID Manager iPhone Data Steward API Data Manager SociaLite: Social DB Language Music GPS Photo Contact Mobile client API Android Friend’s Butlers Friends’ Butlers imap facebook home server

18. Basic Social Applications Single query  personal Butler (3 Datalog rules) Butler contacts other Butlers to return results

19. Applications Enabled by PrPl Finding data in your friends* tera-byte databases (more) Tag: Emma (John) Collective photo album Collaborative tagging Looking up friends’ library & recommendations

20. Search Through Personal DBs Fstar(p) :- Friend(p) Fstar(p) :- Fstar(x), Friend[x](p) Fstar-CurrLoc (p,l) :- Fstar(p), CurrLoc[p](l) Datalog Queries are naturally recursive: including the destination To hide details of Distribution Authentication Optimizations

21. Basic System Credentials Single-sign on: Butler presents a session ticket to other Butlers. Tickets are issued for applications to retrieve blobs from wherever. Extensions Localization User-defined functions Aggregate functions

22. Optimizations Dynamic query: phone to butler, butler to butler Continuous connection: real-time activities Polling based: maintain consistency of a selected portion of the DB Pipelined execution: Return and display results as they come in Six degrees of separation Speed is more important than completeness Toleration of slow/offline servers

23. Preliminary Experimental Results (100 Butlers in EC2)

24. Tail Recursion Optimization Fstar(p) :- Friend(f). Fstar(p) :- Fstar(x), Friend[x](p). AllWeights (count, sum ) :- Fstar(f), Weight[f](w). Recognize tail recursion Visit in a depth-first search Perform reduction in the intermediate nodes E.g. Top 10 songs: 12 sec vs. 100 sec. Butler

25. Concepts in Decentralization Phone as your digital identity Junction: a decentralized platform for ad hoc, social applications Prpl Personal Cloud Butlers Federated storage system Semantic index: database + semantic file system Datalog for distribution and optimization

26. Access Control Facebook 45% do not have any access control API is hard to use Security is as strong as the weakest link Inspiration: E-mail Control access of each e-mail Many un-named lists with nuances

27. Email  Social Topology @Play @Work Enjoying powder at Heavenly! >:-D @play Working from home, sick  @work

28. Friends Come and Go Continuous update! Phone log SMS

29. Filter is More Important than Access Control … Most important optimization in SociaLite! Automatic Clustering  Intelligent Search

30. Decentralization, Open API Phone as your digital identity Junction: a decentralized platform for ad hoc, social applications Prpl Personal Cloud Butlers Federated storage system Semantic index: database + semantic file system Datalog for distribution and optimization Access control Semi-automatically and continuously mined from e-mail Exports different friends list to web portals