12.5. The field wrappers
Fixing an irreducible modulus turns the packed polynomial ring into a
field. Hex.GF2n is the single-word wrapper for GF(2ⁿ) with
n < 64: an element is one UInt64 of coefficients, reduced modulo a
monic degree-n modulus, and the type carries the irreducibility proof
of that modulus so only genuine fields can be formed.
Hex.GF2nPoly is the arbitrary-degree counterpart, backed by a
full GF2Poly rather than a single word. Both expose the field
operations (addition, multiplication, inverse, division) and a
square-and-multiply exponentiation Hex.GF2n.pow.