Method and system for secure multiparty cloud computation

A non-transitory computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method, the method comprising:

• receiving multiple encrypted datasets from multiple clients, wherein an encrypted dataset associated with a client is encrypted from a corresponding plaintext dataset using a unique, client-specific encryption key;
• re-encrypting the multiple encrypted datasets to a target format;
• evaluating a function based on the re-encrypted multiple datasets to produce an evaluation outcome;
• and
• sending the evaluation outcome to the multiple clients, which are configured to cooperatively decrypt the evaluation outcome to obtain a plaintext evaluation outcome.

A computer-executable method, comprising:

• obtaining, by a client of a cloud computing system, an encrypted dataset from a plaintext dataset using a unique encryption key;
• storing the encrypted dataset at the cloud computing system;
• generating a re-encryption key;
• transmitting the re-encryption key to the cloud computing system, thereby allowing the cloud computing system to re-encrypt multiple encrypted datasets received from multiple clients and generate an evaluation result of a function based on the re-encrypted multiple datasets;
• receiving the evaluation result from the cloud computing system;
• cooperating with other clients to decrypt the evaluation result to obtain a plaintext evaluation result.

A computer system comprising:

• a processor;
• a memory;
• a receiving module configured to receive multiple encrypted datasets from multiple clients, wherein an encrypted dataset associated with a client is encrypted from a corresponding plaintext dataset using a unique, client-specific encryption key;
• a re-encryption module configured to re-encrypt the multiple encrypted datasets to a target format;
• an evaluation module configured to evaluate a function based on the re-encrypted multiple datasets to produce an evaluation outcome;
• and
• an output module configured to send the evaluation outcome to the multiple clients, which are configured to cooperatively decrypt the evaluation outcome to obtain a plaintext evaluation outcome.