Social Networking with Frientegrity: Privacy and Integrity with an - - PowerPoint PPT Presentation
Social Networking with Frientegrity: Privacy and Integrity with an Untrusted Provider Ariel J. Feldman Princeton UPenn Joint work with: Aaron Blankstein, Michael J. Freedman, and Edward W. Felten Social Networking with
Social Networking with Frientegrity — Ariel J. Feldman — Usenix Security 8/10/12 1
Joint work with:
Aaron Blankstein, Michael J. Freedman, and Edward W. Felten
Princeton UPenn
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Google Transparency Report Jan. – Jun. 2011
Social Networking with Frientegrity — Ariel J. Feldman — Usenix Security 8/10/12 3 PC World. Dec. 6, 2011
Ars Technica. Mar. 11, 2011
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Server Alice
1 2 3
Bob
1 3 2
http://songshinan.blog.caixin.com/archives/22322 (translated by Google)
(e.g to disguise censorship)
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(sacrifice availability, convenience, etc.) ¡ (who you may not know either) ¡
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Client Client Server Server
Client
(e.g. walls, feeds, friends, FoFs, followers)
Server Server
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Client Client Server Server
Client
State
Encrypted state
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Client Client Server Server
Client
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Server 1
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Server 2
Bob’s profile
Server n Bob
Read Alice’s wall
Verify & decrypt
Alice’s wall Alice’s photo album Alice’s ACL Comment thread
Alice’s profile Optionally entangled Checked for equivocation
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detect equivocation after exchanging 2 messages
Server Alice
1 2 3
Bob
1 3 2
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hroot commits to entire history Let C15 be a server- signed commitment to hroot up to op15
hi = H(hleftChild(i) || hrightChild(i))
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C15 Is C8 consistent with C15?
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C11
Is C11 consistent with C15?
C8 C4 C0
Alice’s ops Bob’s ops Charlie’s ops
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C11
Alice’s ops Bob’s ops Charlie’s ops Bob’s ops
C9
C11
Server
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Bob
Verify & decrypt
Alice’s wall Alice’s photo album Alice’s ACL Comment thread
Server
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Bob
Verify & decrypt
Alice’s wall Alice’s photo album Alice’s ACL Comment thread Alice ¡ Charlie ¡ Bob ¡ Emma ¡ Sean ¡ David ¡
[AGT01]
Server
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Bob
Verify & decrypt
Alice’s wall Alice’s photo album Alice’s ACL Comment thread Alice ¡ Charlie ¡ Bob ¡ Emma ¡ Sean ¡ David ¡
[WGL98]
David, k0 ¡ Bob, k1 ¡ Sean, k2 ¡ Alice, k3 ¡ Charlie, k4 ¡ Emma, k5 ¡
Server
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Bob
Verify & decrypt
Alice’s wall Alice’s photo album Alice’s ACL Comment thread David, k0 ¡ Bob, k1 ¡ Sean, k2 ¡ Alice, k3 ¡ Charlie, k4 ¡ Emma, k5 ¡
Zack, k6 ¡
Server
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Bob
Verify & decrypt
Alice’s wall Alice’s photo album Alice’s ACL Comment thread David, k0 ¡ Bob, k1 ¡ Sean, k2 ¡ Alice, k3 ¡ Charlie, k4 ¡ Emma, k5 ¡ Zack, k6 ¡ Bob, k1’ ¡ David, k0’ ¡
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5K 10K 15K 20K 25K
Object History Size
2 4 6 8 10 12 14
Response Latency (ms)
Write Read
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(collaborative verification)
Constant cost
dominates
500 1000 1500
Object History Size
200 400 600 800 1000
Response Latency (ms)
Read Write
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200 400 600 800 1000
5 10 15 20 25 30 35
10 20 30 40 50
10 100 1000
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