5. The method of claim 1 , further comprising a learning mode to define the membership signature, comprising the steps of: setting, at the computer system, a membership signature to a predetermined initial value; receiving, at the computer system, an initial executable file; extracting, at the computer system, a representative pattern of a predetermined length from the initial executable file; and defining, at the computer system, the membership signature by adding the representative pattern of a predetermined length from the initial executable file to the predetermined initial value of the membership signature.
5. The method of claim 1 , further comprising a learning mode to define the membership signature, comprising the steps of: setting, at the computer system, a membership signature to a predetermined initial value; receiving, at the computer system, an initial executable file; extracting, at the computer system, a representative pattern of a predetermined length from the initial executable file; and defining, at the computer system, the membership signature by adding the representative pattern of a predetermined length from the initial executable file to the predetermined initial value of the membership signature. 6. The method of claim 5 , further comprising the step of: determining, at the computer system, whether the extracted representative pattern of a predetermined length from the initial executable file is already a member of the membership signature.