11. A method as set forth in claim 10 wherein the step of estimating a probability of an exact match includes a second initial step of segregating the candidate signature into a plurality of contiguous blocks of bytes each of which contains no wildcard bytes, and wherein the exact match probability is found by multiplying together probabilities of each of the segregated plurality of contiguous blocks of bytes.
10. A method as set forth in claim 9 wherein the step of estimating a probability of an exact match includes an initial step of replacing bytes that may potentially vary, from the first instance of the undesirable software entity to the second instance, with a wildcard byte that has an exact match with every possible byte.