With the emergence of new technologies and the ubiquitous connec- tivity, large amounts of data are being generated everyday with the need to be stored properly and explored rapidly. In this context, the cloud computing ser- vices have been adopted to face these rising challenges. But in a cloud envi- ronment, data and the application are controlled by the service provider and the customer does not always have the possibility to increase the security level im- posed. This leads users to apply encryption mechanisms before storing their data in the cloud. In this paper we propose a new approach that combines the strengths of both steganography and cryptography called Data Alteration. The technique aims to hide the data by modifying it completely as it remains read- able, meaningful and therefore shows no suspicions to malicious cloud providers and pirates. The proposed appoach was implemented in Java and tested on real- istic datasets in a multi agent systems based architecture.