What are OSNs? Web-based community platforms Presentation and linking of personal data Several hundred Millions of users
Motivation of involved actors: User entertainment
Storing and searching for content User to user interaction Secure storage and communication
Provider profit High profit (ads for many users) Low operational costs (servers,…) Controlled service quality
Our goal: A P2P-platform for OSNs that satisfies users and providers with high quality apps / plugins
Flexible GUI
EventsPersonal
information
Friends,contacts
Social interaction
Pluginarchitecture
Photos
KOM – Multimedia Communications Lab 3
Architecture Design
Current issues with centralized OSNs Lots of operational costs ! Rough estimation: 1$ per year per user Facebook: 450M users
Peer-to-peer approach: Use capacities of user devices (Moore’s law!) Interconnect users with p2p-overlay Provide all functionality in a distributed way Shift the load and costs to the users
LifeSocial: Researched since end of 2007 Ca. 10 diploma / bachelor theses on this topic Ca. 20 researcher and student programmers
KOM – Multimedia Communications Lab 4
User View: Rich Functionality
Wide set of functionality Plugin-based application:
GUI-Framework like in Eclipse Fast and user-friendly performance
KOM – Multimedia Communications Lab 5
Provider View: Monitoring and Management
Integrated monitoring and management Totally distributed, precise and cheap Controls service quality of p2p system
Monitoring global system statistics Statistics on
Statistical information: avg, min, max, standard dev., sum,...
Management of system quality Following principles of autonomic computing: Automated
adaptation of system configuration to meet quality goals
See: K. Graffi et al., “Monitoring and Management of Structured Peer-to-Peer Systems” In: IEEE Peer-to-Peer Computing '09 (IEEE P2P’09), September 2009.
P2P Overlay
Monitoring
Analysis andPlanning
Execute
Preset QualityGoals
SystemDynamicsSystem
Performance Costs Social Metrics
Number of peers CPU / bandwidth usage Friends
Data retrieval delays
Objects in Cache Groups
… … …
KOM – Multimedia Communications Lab 6
Architecture Details of LifeSocial
GUI Framework: Extendable and flexible Provides an interface to the Plugins
Plugins: Functionality of online social networks (and more) Easy Plugin-to-Plugin communication
Over shared storage Over Plugin ID based messaging
Information Cache: Enables the Plugins to reuse the data Hides the asynchronous effects of distributed data storage
Monitoring and Management: Provides statistics on system behavior Enables the provider to control the service quality
Secure Storage Dispatcher + access control: Storage and retrieval of data objects (PAST) Replicates data and guarantees their availability
Structured Peer-to-Peer Overlay Connects the nodes and enables inter-peer communication
See: K. Graffi et al., “A Distributed Platform for Multimedia Online Communities” In: IEEE International Symposium on Multimedia '08 (IEEE ISM’09), December 2008.
KOM – Multimedia Communications Lab 7
Peer and Plugin Communcation Principles
FreePastry – based on Pastry, DHT Documents are mapped to peers:
Every Document-ID has a responsible peer Contacted by document owners and requesters
FreePastry routes to responsible peer Add-on PAST manages the data replication
Plugin-to-Plugin communication Over Plugin ID based messaging
Analog to ports in transport layer Over shared storage
Personal data is NOT stored on user’s device Additional fine-grained access control in place
Node 1008 queries item 3000
Responsible peer found
16221009-1622
22072012-2207
29062683-2906
34852907-3485
20111623-2011
709660-709
659612-659
26822208-2682
6113486-…0-611
Responsible for 1008 + 1024
3
Use shortcuts/fingers…
12
Responsible for 2207 + 512Responsible
for 3000
1008710-1008
See: K. Graffi et al., “A Distributed Platform for Multimedia Online Communities” In: IEEE International Symposium on Multimedia '08 (IEEE ISM’09), December 2008.
Principle of ID-based routing
Example data object
Structured p2p overlay
KOM – Multimedia Communications Lab 8
Document Types, Obvious Storage Keys
High granularity of stored data objects
Better load balancing of the resources
Used for Atomic data: profiles, login info, “emails” Linked lists: friend lists, groups, multicast
Allows for complex data structures
User Albums
storage key = „user name“+“album“
List of user albums:1. storage key a2. storage key b3. storage key c4. storage key d
...
storage key a
List of images:1. storage key x2. storage key y3. storage key v4. storage key r
...
User album A
storage key x
image
Image x
storage key y
image
Image y
storage key d
List of images:1. storage key n2. storage key m3. storage key k4. storage key l
...
User album D
storage key n
image
Image n
storage key m
image
Image m
Profile
storage key p = “User_Kalman_Graffi”
Name: KalmanAge: 27
University:Technische Universität Darmstadt
See: K. Graffi et al., “A Distributed Platform for Multimedia Online Communities” In: IEEE International Symposium on Multimedia '08 (IEEE ISM’09), December 2008.
KOM – Multimedia Communications Lab 9
Data Positioning in the Network
User albums
object key = „user name“+“album“
List of user albums:1. object key a2. object key b3. object key c4. object key d
...
object key a
List of images:1. object key x2. object key y3. object key v4. object key r
...
User album A
object key x
image
Image xobject key y
image
Image y
object key d
List of images: 1. object key n 2. object key m 3. object key k 4. object key l
...
User album D
Distributed Storageà Object ID based Routing
P2P Overlayà Peer ID based Routing
Internetà IP based Routing
replica replica
replicareplica
replica
request
responsibility range
KOM – Multimedia Communications Lab 10
Practical Distributed Access Control
Mechanism: Prepare confidential data
Start: “SharedItem” Symmetrically encrypt objects
use “object keys” Asymmetrically encrypt object keys
use “user keys” (publicly available) Append encrypted object keys to object
Result: “CryptedItem”
Features: Replicability:
Every peer may store CryptedItems Access control:
Only privileged users can decrypt it Compatibility to FreePastry/PAST:
Fully distributed, PKI integrated
How to provide access control in a distributed environment?
Goal: Assign read-rights on objects to privileged users
SharedItemobjectID Header
Privileged users
Payload
Signed CryptedItem
objectID Key list
userID A – key AuserID B – key BuserID C – key C
Byte arraycontainingencrypted
SharedItem
Symmetric Key
PubUser A
Encrpytedwith
Symmetric Key
PubUser B
Encrpytedwith
…
PubUser A
PubUser B
[userID A] =
[userID B] =
ext
ract
1
Serialized and encrypted withsymmetic key2
userIDsare public keys
3
wrap symmetric keywith public key
4
5
See: K. Graffi et al., “Practical Security in P2P-based Social Networks” In: IEEE Local Computer Networks '09 (IEEE LCN’09), October 2009.
KOM – Multimedia Communications Lab 11
LifeSocial Plugin Overview
Everything is a Plugin Stand-alone applications (apps) Communicate over storage or with messages Mandatory or optional Implement OSN functionality (and more)
Traditional OSN functionality Login, Profile, Friends, Groups, Search,
Photos, Messages, Chat
Extended OSN functionality Multi-chat, Whiteboard, Calendar, Tweets
Extendability Plugins are OSGI-based Can be loaded on runtime on demand Version updates over the Internet possible Planned “Plugin-Store” hosting new Plugins
Rapid application development Plugin interfaces are open and combinable Allows for Unix-style reuse of components New Plugins can be included in the
monitoring and management framework
See: K. Graffi et al., “LifeSocial.KOM: A P2P-based Platform for Secure Social Online Networks” submitted to IEEE Networking ‘10, January 2010.
KOM – Multimedia Communications Lab 12
Summary on LifeSocial
IT solutions for social networks Currently centralized and very costly Scales only with high monetary invests
Distributed, p2p-based platforms Data storage is totally distributed Costs are shared among the users
LifeSocial Operational prototype Secure, reliable storage and messaging Monitoring mechanism to observe
(and control) the quality of service Rich, extendable functionality through
Plugin-based architecture See videos on www.lifesocial.org
Analysis of needs:
Users requirements Storing and searching for content User to user interaction Security
System provider requirements Low operational costs Controlled quality of service High profit
Next steps: Fine tuning and final consolidation Run Internet-wide beta-test Deployment
