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e POST Serverless Email System

e POST Serverless Email System. http://www.epostmail.org/ POST: A Decentralized Platform for Reliable Collaborative Applications Seo, Dong Mahn 16 th June, 2005. Contents. Introduction Background Scoped Overlays POST Design ePOST Design Related Work Current Version Conclusions.

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e POST Serverless Email System

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  1. ePOST Serverless Email System http://www.epostmail.org/ POST: A Decentralized Platform for Reliable Collaborative Applications Seo, Dong Mahn 16th June, 2005

  2. Contents • Introduction • Background • Scoped Overlays • POST Design • ePOST Design • Related Work • Current Version • Conclusions

  3. Introduction

  4. Introduction (1) • POST • Three basic services • Secure persistent single-copy storage • Metadata based on single-writer logs • Event notification • Wide range of collaborative applications • Scalability, resilience and self-organization • From users • CPU, disk space, network bandwidth

  5. Introduction (2) • ePOST • Cooperative, serverless email system • Storage, Network bandwidth from users • Provides • A severless, peer-to-peer email service • Secure email among ePOST users • An organically scaling service that requires no dedicated hardware • Very high availability and data durability • Compatibility with POP/IMAP clients, SMTP mail servers

  6. Background (1) • Email Systems • Simple Mail Transfer Protocol (SMTP) • Post Office Protocol (POP3) • Internet Message Access Protocol (IMAP) • Webmail

  7. Background (2) • Peer-to-Peer Overlays • Pastry • structured overlay network • self-organizing, highly scalable, and fault tolerant • unique identifier (160-bit id space)

  8. Background (3) • Peer-to-Peer Overlays • PAST • distributed storage system • Distributed Hash Table (DHT) • Content Hash Blocks • Certificate Blocks • Public-Key Blocks

  9. Background (4) • Peer-to-Peer Overlays • Scribe • group communication system • 160 bit groupId • multicast tree

  10. Scoped Overlays (1) • Design • Multi-Ring Protocol above the Key-Based Routing (KBR)

  11. Scoped Overlays (2) • Ring structure

  12. Scoped Overlays (3) • Gateway nodes • one in each ring • use the same nodeId in each ring • Routing • target ringId • anycast • Global lookup • ringId

  13. Scoped Overlays (4) • Multi-level ring hierarchies

  14. POST Design (1) • User accounts • identity certificate as a certificate block • secure hash of the users’ name as the handle • description of the user • contact address of the user’s current trusted node • any references to public metadata associated with the account • public-key block • signed with user’s private key

  15. POST Design (2) • Single-copy store • convergent encryption • allows a message to be disclosed to selected recipients • ciphertext (cryptographic & cipher)

  16. POST Design (3) • Event notification • alert users and groups of users to certain events • availability of a message. change in the state of a user, change in the state of a shared object • Advanced Encryption Standard (AES) with a unique session key

  17. POST Design (4) • Metadata • single-writer logs • Ivy • The log head and each log record are stored at a different set of nodes. • Garbage collection • removing objects from the DHT • Lifetime

  18. POST Design (6) • POST Security • Threat model • Data privacy • Data integrity • Data durability • Denial of service • Freeloading

  19. ePOST Design (1)

  20. ePOST Design (2) • Email storage • Email messages and MIME components in POST’s single-copy store. • Email delivery • using POST’s notification service • Email folders • encrypted POST log

  21. ePOST Design (3) • Incremental Deployment • interoperate with server-based email infrastructure • Management • Software distribution • Storage • Access • Discussion • Feasibility, Mailing Lists, Spam

  22. Evaluation (1) • Timeline • from Sept. 19, 2005 to Nov. 12, 2004 • average 26 nodes • Linux and Windows

  23. Evaluation (2)

  24. Evaluation (3)

  25. Evaluation (4)

  26. Evaluation (5)

  27. Evaluation (6)

  28. Evaluation (7)

  29. Evaluation (8)

  30. Evaluation (9)

  31. Evaluation (10) • Single-Copy Store • reduce the storage load by 6.1% • 30 users • 300,000 email messages • 2.8 GB • reduced to 3.2GB of unique data • savings of 15.5% • 254% increase in the effect of the single-copy store.

  32. Evaluation (11)

  33. Evaluation (12)

  34. Related Work • Collaborative Applications • SENGMSG program, FTP, SMTP, POP3, IMAP • Lotus Notes, MS Exchange • Scalability • Porcupine System • Hotmail, Google • Security • spam, phishing scams • PGP, GPG, DNS tricks • Peer-to-Peer Applications • DHT • OceanStore project, Kademlia, eDonkey2000 • Coral-CDN, OpenDHT

  35. Current Version • ePOST 2.4.2 • 27 May 2005 • Rings • Rice University Ring (rice.epostmail.org) • Open Membership Ring (open.epostmail.org) • based on PlanetLab nodes • Future Features • individual domain names • multiple, simulations proxies • multiple ePOST accounts

  36. Conclusion • POST • decentralized, serverless messaging system • highly resilient and scalable messaging service • enduring confidentiality, data integrity, and authentication • ePOST • easily provide • instant messaging, newsgroups, calendars, and shared whiteboards

  37. Thank you !

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