Security in Computing 5th Edition by Shari Lawrence Pfleeger, Charles P Pfleeger, Jonathan Margulies

Exercise 7

Show that if longitudinal parity is used as an error detection code, values in a database can still be modified without detection. (Longitudinal parity is computed for the nth bit of each byte; that is, one parity bit is computed and retained for all bits in the 0th position, another parity bit for all bits in the 1st position, etc.)