Integrity of tagged data

1. Field of the Invention A method and computer apparatus are presented for providing a secure data architecture for computer memory of a processor. The apparatus comprises a memory unit and a processing unit. Data are stored in the memory unit and manipulated by the processing unit, which is programmed to implement the data architecture. Tagged single data words are formed by concatenating a tag to each of the single data words. Each of the tags takes a value that corresponds to the data type of the single data word to which it is concatenated. A data multiword is creating by concatenating tagged single data words having the same data type. The data multiword is stored within a location in the computer memory, the location selected to ensure alignment of the data multiword in accordance with its length. An effective tag value is constructed for the data multiword by concatenating all of its single word tags. An operation is prevented from being performed on the data multiword if the effective tag value is not one of a predetermined list of valid effective tag values for the operation.