1. Implementing e-Auctions with Sharemind Md. Sadek Ferdous 12th November 2008

2. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Types of Auction Possible exploitations in Auction Advantages of e-Auction Auction steps Security considerations Design Issues Sharemind Proposed solution Design issues in the solution Suggestion Conclusions Overview

3. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Mention of auction in as early as 500 B.C One of the main forms of selling, buying and exchanging goods Objective is the efficient trading of commodities Auction

4. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Open cry auction --English and Dutch auction Sealed bid auction --Sealed bid first price auction and Vickrey auction Multi item auction --Discriminative auction, Non-discriminative --Combinatorial and Walrasian Auction All pay auction Buyout auction --Permanent & Temporary No reserve (NR) auction Reserve auction Reverse auction Round robin auction Types of auctions

5. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Bid shielding Collusion Bid schilling Bid sniping Bid siphoning Mispresented or non-existent item Exploitations in auctions

6. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Shorthand for Electronic auction One of the major sources of revenue for e-Commerce eBay with yearly revenue of 7.67 Billion USD is the main actor to popularize the term e-Auction e-Auction

7. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions No time constraint No geographical constraint Potentially large number of sellers and buyers Advantages

8. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Mode of payment Fraudulancy Posting Dependable & Security Guarding against problems of traditional auctions Challenges

9. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Initialization Registration Bidding Winner determination Auction steps

10. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Unforgeability Non-repudiation Anonymity Public verfiability Robustness Efficiency Fairness Security considerations

11. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Trust issues Anonymity issues Bid authentication issue Design Issues

12. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Sharemind A framework for secure computation based on secret sharing. In secret sharing, a secret value is divided among several values known as shares Origianal secret can be reconstructed only if all the shares are known. In Sharemind, there are miner nodes and controller node. Controller divides the secret into share and sends them to the miners, miners perform operations on those shared values. Currently add or multiply two shared values, multiply a shared value by a constant, extract bits from shared value, determine if the two shared values are equal and if not, which one is greater.

13. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Sharemind with Group Signature Scheme Auction type: Sealed bid Proposed solution

14. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Auctioneer Bidder Registrar Miners Controller List of parties

15. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Auctioneer sets up an auction and advertises it to the public. Registrar sets up the group certificate. Auction Steps Initialization:

16. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Auction Steps Registration Bidder creates a pair of public and private key. Sends a message to the auctioneer. Auctioneer provides a token. Bidder sends this token and his public key to the registrar. Registrar issues a group certificate and identifier for him.

17. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Auction Steps Bidding Bid is sent to the controller. Controller signs them using private key, and then divides into three share, signs them again using group certificate and sends them to the miners. The signature with private key adds veriability & group signature adds anonymity. Miners verify the bid using group public key and stores them in their local databases. When bid ends, the miners determine the highest bid & send that bid and the signature to the auctioneer.

18. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Auction Steps Winner determination The auctioneer publishes the winning bid. The winning bidder contacts with his identifier and signature The auctioneer contacts the registrar to get back the public key and the token associated with that id and receives them. The auctioneer comapres the two signatures, if it matches, the winner’s id is published. If more than one winner found, a second phase of auction may take place.

19. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Trust issues Anonymity issue Bid authentication issue Design issues of the architecture

20. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Multiple controllers Simultanenous connections Hybrid database Enhancements of Sharemind

21. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions This talk has: described various types of auction and different exploitation methods in auction, provided an overview on advantages, security considerations and design issues in e-Auction, presented a novel approach on how to integrate Sharemind for e-Auction using group signature scheme, and suggested a few enhancements based on the proposal. Conclusions

22. Implementing e-Auctions with Sharemind November 12, 2008 Auction e-Auction Proposed Solution Conclusions Thank you. Questions or comments?