2018 Symposium Posters

Posters > 2018

Private Preserving Credit System with Cryptographic Currency


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Primary Investigator:
Feng Li

Project Members
Tianchong Gao; Feng Li
Abstract
The utility of cryptographic currencies, e.g., Bitcoin, is inherently restricted by privacy and latency concerns. Hence some payment protocols, such as the lightning network, have been introduced. We find that building a credit network as a second layer on top of a cryptographic currency helps anonymize transactions. Also, the credit network further extends the functionality of the original blockchain. It allows users to temporarily spend more money than they own. However, setting up the credit limit in a way that protects the creditor and also preserves the privacy of the debtor is a challenge. In this project, we build a credit management system. Specifically, in order to avoid frequent credit applications from a single debtor, we design a cyclic blockchain to store application information. We also embed Bloom filter in the blockchain and add differential-privacy noise to it to enhance the privacy of the original application address. We design a dispute flow that no party to these transactions and contracts (a credit manager, debtor, or creditor) is able to cheat the others, while the privacy of all parties is preserved.