High Quality Content by WIKIPEDIA articles! In Boolean logic, the algebraic normal form (ANF) is a method of standardizing and normalizing logical formulas. As a normal form, it can be used in automated theorem proving (ATP), but is more commonly used in the design of cryptographic random number generators, specifically linear feedback shift registers (LFSRs). A logical formula is considered to be in ANF if and only if it is a single algebraic sum (XOR) of a constant and one or more conjunctions of the function arguments. ANF is also known as "Zhegalkin polynomials" (Russian: полиномы Жегалкина) and as "Positive Polarity (or Parity) Reed-Muller" expression.