Electronic information system for electronic voting or online auctions, prevents transmitting parties from proving to information buyer that they have transmitted information or not

摘要

Processing means (121, 12n) are each dedicated to a specific transmitting party (A1, An) and make a commitment to a first encryption by randomly generating a first parameter vector and sending an encryption of this vector as a registration to a mixing net. The registration is recorded in a storage means (15) within the system and the mixing net runs all the registrations to obtain a list of transmitting parties in a transformed format. Each transmitting party makes a commitment to a second encryption by randomly choosing a second parameter vector, sending a commitment to the specific information being sent to a receiving party (RP1) and sending the second parameter to the dedicated processing means. This processing means makes a commitment to a re-encryption by randomly choosing a third parameter vector, sending a commitment to the third parameter vector and sending a non-interactive designated verifier zero-knowledge proof of knowledge (NIDVP) to the tra nsmitting party. This party then sends a disclosure of the commitments to the dedicated processing means, making it possible for this means to create an encrypted version of the specific information based on the sum of the second and third vectors. The dedicated processing means sends this encrypted version with a signature made by this means to a storage means (16) within the mixing net and the latter makes a number of re-encryptions and mixings of the encrypted version before finally making a decryption, the result of which is sent to the receiving party in the form of specific information from all transmitting parties. Any transmitting party is prevented from being able to prove to an information buyer than the transmitting party has transmitted the specific information or not transmitted anything at all. The processing means each comprise a smart card with a common public NIDVP key stored on it during manufacture. A common secret NIDVP key is made public after the smart cards have been distributed. The specific information concerns a vote or auction bid.