Probabilistic Escrow of Financial Transactions with Cumulative Threshold Disclosure

Abstract. We propose a scheme for privacy-preserving escrow of financial transactions. The objective of the scheme is to preserve privacy and anonymity of the individual user engaging in financial transactions until the cumulative amount of all transactions in a certain category, for example all transactions with a particular counterparty in any single month, reaches a pre-specified threshold. When the threshold is reached, the escrow agency automatically gains the ability to decrypt the escrows of all transactions in that category (and only that category). Our scheme employs the probabilistic polling idea of Jarecki and Odlyzko [JO97], amended by a novel robustness mechanism which makes such scheme secure for malicious parties. When submitting the escrow of a transaction, with probability that is proportional to the amount of the transaction, the user reveals a share of the key under which all his transactions are encrypted. Therefore, the fraction of shares that are known to the e...

• Type: Conference
• Year: 2005
• Where: FC
• Authors: Stanislaw Jarecki, Vitaly Shmatikov
• Keywords: Escrow Agency, FC 2005, Privacy-preserving Escrow, financial Transactions