Portability | portable |
---|---|

Stability | experimental |

Maintainer | erkokl@gmail.com |

Simple usage of polynomials over GF(2^n), using Rijndael's finite field: http://en.wikipedia.org/wiki/Finite_field_arithmetic#Rijndael.27s_finite_field

The functions available are:

*pMult*- GF(2^n) Multiplication
*pDiv*- GF(2^n) Division
*pMod*- GF(2^n) Modulus
*pDivMod*- GF(2^n) Division/Modulus, packed together

Note that addition in GF(2^n) is simply `xor`

, so no custom function is provided.

# Documentation

Helper synonym for representing GF(2^8); which are merely 8-bit unsigned words. Largest term in such a polynomial has degree 7.

(<*>) :: GF28 -> GF28 -> GF28Source

Multiplication in Rijndael's field; usual polynomial multiplication followed by reduction
by the irreducible polynomial. The irreducible used by Rijndael's field is the polynomial
`x^8 + x^4 + x^3 + x + 1`

, which we write by giving it's *exponents* in SBV.
See: http://en.wikipedia.org/wiki/Finite_field_arithmetic#Rijndael.27s_finite_field.
Note that the irreducible itself is not in GF28! It has a degree of 8.

NB. You can use the `showPoly`

function to print polynomials nicely, as a mathematician would write.

multAssoc :: GF28 -> GF28 -> GF28 -> SBoolSource

States that multiplication is associative, note that associativity proofs are notoriously hard for SAT/SMT solvers

polyDivMod :: GF28 -> GF28 -> SBoolSource