A method for selectively scrambling data within a memory associated with a computing device based on data tagging. The computing device may define security domains that are protected. Data generated by an application may be packaged as a data bus transaction having tagging information describing the application and/or the data. The data bus transaction may be transmitted over a bus of the computing device to a memory, such as internal memory, where the computing device may compare the tagging information to stored information describing security domains. When the data is determined to be protected based on the tagging information, the computing device may perform scrambling operations on the data. In an aspect, the tagging information may describe a virtual machine used to execute various applications on a processor. In another aspect, the tagging information may define destination memory addresses or content protection bit values.