Abstract: A client-server computer system (10) for a client (12) to search for a keyword in at least partially homomorphically encrypted documents (18) stored in a server (14) is disclosed. The client-server computer system (10) is configured as follows. The client (12) applies probabilistic symmetric encryption to a keyword to form a probabilistically encrypted keyword to form a first result. The client (12) applies deterministic symmetric encryption to the keyword to form a deterministically encrypted keyword, then computes a modular inverse of the deterministically encrypted keyword, and then applies at least partially homomorphic encryption to the modular inverse deterministically encrypted keyword to form a second result. The client (12) uses a session key to hash the first result to form a hash result. The client (12) combines the first result and second result to form a third result. The client (12) encrypts the third result and the hash result using a private key to generate the search query.

Abstract: A client-server computer system (10) for a client (12) to search for a keyword in at least partially homomorphically tencrypted documents (18) stored in a server (14) is disclosed. The client-server computer system (10) is configured as follows. The client (12) applies probabilistic symmetric encryption to a keyword to form a probabilistically encrypted keyword to form a first result. The client (12) applies deterministic symmetric encryption to the keyword to form a deterministically encrypted keyword, then computes a modular inverse of the deterministically encrypted keyword, and then applies at least partially homomorphic encryption to the modular inverse deterministically encrypted keyword to form a second result. The client (12) uses a session key to hash the first result to form a hash result. The client (12) combines the first result and second result to form a third result. The client (12) encrypts the third result and the hash result using a private key to generate the search query.

Abstract: A system and method for preserving the privacy of data while processing of the data in a cloud. The system comprises a computer program application and a client encryption key, The system is operable to encrypt the computer program application and data using the client encryption key; upload the encrypted computer program application and encrypted data in the cloud; enable the computer platform to undertake processing of the encrypted data in the cloud using the encrypted computer program application; output encrypted processing results; and, enable decryption of the encrypted processing results using the client encryption key.

Abstract: A system and method for preserving the privacy of data while processing of the data in a cloud. The system comprises a computer program application and a client encryption key, The system is operable to encrypt the computer program application and data using the client encryption key; upload the encrypted computer program application and encrypted data in the cloud; enable the computer platform to undertake processing of the encrypted data in the cloud using the encrypted computer program application; output encrypted processing results; and, enable decryption of the encrypted processing results using the client encryption key.