Methods and apparatus for providing data security, in particular for cloud computing environments, are described. In an embodiment, a software component monitors events at a node in a computing system and on detection of an event of a particular type, interrupts a message associated with the event. Before the message is allowed to continue towards its intended destination, a security template is selected based on the message (e.g. the data in the message and identifiers within the message) and this template is used to determine what data protection methods are applied to each data element in the message. A modified data packet is created by applying the security template and then this modified data packet is inserted into the message in place of the data packet in the interrupted message.