Abstract: A method for operating an aggregator in an electronic commerce system includes receiving ciphertexts and signatures transmitted from multiple clients, each ciphertext encrypting noisy plaintext data of a category of information for a user that purchased a product, generating sums of the ciphertexts and the signatures, verifying the sum of the ciphertexts with a homomorphic signature system based on the sum of the signatures and homomorphic verification data, decrypting the sum of the ciphertexts in a private stream aggregation (PSA) process based on homomorphic decryption data to generate a sum of noisy plaintext data in response to a success of the verification, and identifying aggregate statistical information transmitted from the clients based on the sum of noisy plaintext data while preserving differential privacy of the clients.

Abstract: A method for operating an aggregator in a private stream aggregation (PSA) system has been developed. The method includes receiving a plurality of encrypted messages from a plurality of clients, each encrypted message corresponding to a vector in a learning with errors (LWE) public key, adding, the plurality of encrypted messages to generate an aggregate data set, extracting a summation of a plurality of error vectors in the plurality of encrypted messages from the aggregate data set, decrypting the summation of the encrypted data contained in the plurality of encrypted messages using a private key stored in the memory of the aggregator to generate a plaintext sum of noisy data generated by the plurality of clients, and generating, with the processor, an output of the plaintext sum of noisy data that preserves differential privacy of each client in the plurality of clients.

Abstract: A method for operating an aggregator in an electronic commerce system includes receiving ciphertexts and signatures transmitted from multiple clients, each ciphertext encrypting noisy plaintext data of a category of information for a user that purchased a product, generating sums of the ciphertexts and the signatures, verifying the sum of the ciphertexts with a homomorphic signature system based on the sum of the signatures and homomorphic verification data, decrypting the sum of the ciphertexts in a private stream aggregation (PSA) process based on homomorphic decryption data to generate a sum of noisy plaintext data in response to a success of the verification, and identifying aggregate statistical information transmitted from the clients based on the sum of noisy plaintext data while preserving differential privacy of the clients.

Abstract: A method for operating an aggregator in a private stream aggregation (PSA) system has been developed. The method includes receiving a plurality of encrypted messages from a plurality of clients, each encrypted message corresponding to a vector in a learning with errors (LWE) public key, adding, the plurality of encrypted messages to generate an aggregate data set, extracting a summation of a plurality of error vectors in the plurality of encrypted messages from the aggregate data set, decrypting the summation of the encrypted data contained in the plurality of encrypted messages using a private key stored in the memory of the aggregator to generate a plaintext sum of noisy data generated by the plurality of clients, and generating, with the processor, an output of the plaintext sum of noisy data that preserves differential privacy of each client in the plurality of clients.