Title: Blood on the Database: How Algorithms for Testing Blood Samples can be Used for Database Integrity Abstract: This talk discusses combinatorial group testing, which began from work on detecting diseases in blood samples taken from GIs in WWII. Given a parameter d, which provides an upper bound on the number of defective (e.g., diseased) samples, the main objective of such problems is to design algorithms that identify all the defective samples without explicitly testing all n samples. This classic problem has a number of interesting modern applications, and we describe several such applications as well as new algorithms. In particular, we address the problem of providing a way to protect against the "Ferris Bueller" attack, so as to identify which records of a database have been changed after an unauthorized intrusion, while using no additional memory.