A reduction operation is utilized in an arithmetic operation on two binary polynomials X and Y over GF, where an irreducible polynomial Mm=tm+am\u22121tm\u22121+am\u22122tm\u22122+. Microfibers of the invention can be prepared by imparting fluid energy, typically in the form of high-pressure water jets, to a highly oriented, highly crystalline, aliphatic polyester film to liberate microfibers therefrom. A position adjuster for the piston moves it axially without rotation of the piston ports out of alignment with inlet ports in the housing.