Secure E-Cash Transaction System By Anirudha Jadhav & Tirumal Panganamala Advisor: Thomas Schwarz Ph.D. Overview Introduction Basic System Life Cycle of Micropayment Security Analysis Questions Introduction Growth of E-Commerce – U.S. retail e-commerce sales for 3rd quarter of 2007 are $34.7 billion E-Commerce Payment Method – Identity Based Senior Design: Implement a Secure E-Cash Transaction System that provides user anonimity and untraceable transactions. Basic System There are 3 parties in our E-cash system: 1. E-Buyer – the party that wishes to buy a product and make payment. 2. E-Merchant – the party who is selling the product and is receiving the payment. 3. E-Bank – the party that manages the buyer and merchant’s accounts. Basic System Monetary transactions based on micro payments (tokens) using Micro payment Certificate (MPC). MPC is a data file. Information on MPC is protected through encryption (blinding). Blinding is done by applying a blinding factor. Therefore, user privacy is protected and untraceable transactions are guaranteed. Basic System Basic System - - Payments are made using a chain of hash values where each hash value represents 1 token. Ex: A chain with 10 hash values represents 10 tokens, worth 10 x value of single token. Start with random number x and hash function H. To get the hash chain, apply the hash function repeatedly to each subsequent value. Basic System x -> H(x) = W1 First hash chain value H(W1) = W2 H(W2) = W3 H(W3) = W4 . . . H(Wn-1) = Wn Last hash chain value Basic System Life Cycle of Micropayment Life Cycle of Micropayment - $100 $100 E-buyer’s Account GCF – Generic Certificate Fund Life Cycle of Micropayment Security Analysis Goal – – – Perform an in-depth technical security analysis Investigate and resolve vulnerabilities in the E-cash system. Report the sensitivity of data in terms of C.I.A: - Confidentiality -Preserve restrictions on information access - Integrity - Guarding against improper information modification - Availability – Ensure timely, reliable access and use of information Security Analysis • Examined various implementation vulnerabilities that made E-Cash payment system insecure For each vulnerability: • Threat Analysis • Risk Analysis • Security Analysis Threat Analysis: – – In depth assessment of possible threats to the system To identify the technical causes of each security issue and their consequences An assessment of the probability of the occurrence of each security vulnerability A comparison of the cost of risk vs. cost of protection Recognize or provide a solution for each vulnerability Risk Analysis: – – – Security Analysis Login Authentication – Threat Analysis: User privacy is crucial in our E-cash transaction system The growth of identity thefts due to phishing has further influenced the necessity for robust user login schemes classic scenario: user enters in login details and is forwarded to a website that is very similar to desired site but is a malicious site implemented by the hacker to harvest user personal/monetary data – Risk Analysis: Have user create a pass phrase upon account setup Pass phrase will display after login to assure authenticity Security Analysis Data in transit – Threat Analysis: While in transit from one party to another, important data can be sniffed (e.g. MPC submitted to E-bank) – Risk Analysis: Proposed solution is to use cryptographic protocols such as SSL, which provide secure communications across the internet. SSL is commonly used with HTTP to form HTTPS. By implementing HTTPS for our system, we can provide secure web pages for our e-commerce system. Security Analysis Data Integrity – Threat Analysis: During monetary transactions, data on MPC should not be altered by any party. – Risk Analysis: To guarantee integrity of data, we implemented private key encryption to sign finalized MPC. Any further modification to the MPC in transit will result in an invalid MPC. Conclusion Growth of E-commerce Basic System Lifecycle of Micro Payment Security Analysis Questions?