Abstract: A method of protection of memory contents in a computer which includes the steps of loading a program into the computer and executing such program so that the memory contents of the computer are used to create and store on the same computer cryptographic hash tags uniquely identifying the contents for each of blocks of memory content of selected and consistent size and their location and applying this to all of the memory contents, analyzing the hash tags so as to identify those that have an identical memory content, recording such results of such analysis, then effecting a transfer to an independent memory a copy of the hash tags and the associated memory blocks as well as the other information regarding their location this being with the exception where the contents of a block are identical, and then transferring only one copy of such contents.