Digital signatures having revokable anonymity and improved traceability

Abstract

A method of authenticating electronic data is disclosed. In the preferred embodiment, when a Receiver makes a request to a Signer (e.g., a bank customer asks the bank to issue E-Coin), the Receiver includes a “hint generation value” in the request, and from the hint generation value, a “hint value” is derived and recorded on a signing transcript. The hint generation value is essentially an encrypted version of the request submitted from the Receiver to the Signer. When a merchant/Verifier transmits deposit signatures corresponding to spent E-Coin to be deposited, the transmitted signature is decrypted and blinded by the Signer in the same manner as that used to create the hint value. Thus, the encrypted incoming deposit signature from the merchant/Verifier should match the hint value stored on the signing transcript, confirming that the E-Coin is valid without revealing any identifying information about who spent the E-Coin, i.e., anonymity is preserved. If the incoming encrypted deposit signature does not match a hint value in the signing transcript, the bank immediately knows that counterfeit E-Coin is being circulated and can take the steps necessary to stop any further illicit transactions and attempt to identify the source of the corruption.

Dependencies are inferred from the claim text.