This chapter is from the book
7.6 Integrity
Integrity means preventing Bart the bad guy from changing infograms en route. Most fortress implementations deal with integrity as a side issue of privacy. The assumption is that if Bart can't read the message, he can't change it. Even more secure algorithms exist that can ensure that Bart can't even randomly change the infogram, but I won't cover those here. These are standard security algorithms that are not specific to fortresses.