A system and method for preserving the privacy of data while procesing 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 aplication 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 procesing results; and enable decryption of the encrypted procesing results using the client encryption key.