diff options
Diffstat (limited to 'crypto/src/pqc/math/linearalgebra/PolynomialRingGF2.cs')
| -rw-r--r-- | crypto/src/pqc/math/linearalgebra/PolynomialRingGF2.cs | 286 |
1 files changed, 0 insertions, 286 deletions
diff --git a/crypto/src/pqc/math/linearalgebra/PolynomialRingGF2.cs b/crypto/src/pqc/math/linearalgebra/PolynomialRingGF2.cs deleted file mode 100644 index 9bc3fcd31..000000000 --- a/crypto/src/pqc/math/linearalgebra/PolynomialRingGF2.cs +++ /dev/null @@ -1,286 +0,0 @@ -using System; - -namespace Org.BouncyCastle.Pqc.Math.LinearAlgebra -{ - /** - * This class describes operations with polynomials over finite field GF(2), i e - * polynomial ring R = GF(2)[X]. All operations are defined only for polynomials - * with degree <=32. For the polynomial representation the map f: R->Z, - * poly(X)->poly(2) is used, where integers have the binary representation. For - * example: X^7+X^3+X+1 -> (00...0010001011)=139 Also for polynomials type - * Integer is used. - * - * @see GF2mField - */ - public class PolynomialRingGF2 - { - - /** - * Default constructor (private). - */ - private PolynomialRingGF2() - { - // empty - } - - /** - * Return sum of two polyomials - * - * @param p polynomial - * @param q polynomial - * @return p+q - */ - - public static int Add(int p, int q) - { - return p ^ q; - } - - /** - * Return product of two polynomials - * - * @param p polynomial - * @param q polynomial - * @return p*q - */ - - public static long Multiply(int p, int q) - { - long result = 0; - if (q != 0) - { - long q1 = q & 0x00000000ffffffffL; - - while (p != 0) - { - byte b = (byte)(p & 0x01); - if (b == 1) - { - result ^= q1; - } - p = Utils.UnsignedRightBitShiftInt(p, 1); - q1 <<= 1; - - } - } - return result; - } - - /** - * Compute the product of two polynomials modulo a third polynomial. - * - * @param a the first polynomial - * @param b the second polynomial - * @param r the reduction polynomial - * @return <tt>a * b mod r</tt> - */ - public static int modMultiply(int a, int b, int r) - { - int result = 0; - int p = Remainder(a, r); - int q = Remainder(b, r); - if (q != 0) - { - int d = 1 << Degree(r); - - while (p != 0) - { - byte pMod2 = (byte)(p & 0x01); - if (pMod2 == 1) - { - result ^= q; - } - p = Utils.UnsignedRightBitShiftInt(p, 1); - q <<= 1; - if (q >= d) - { - q ^= r; - } - } - } - return result; - } - - /** - * Return the degree of a polynomial - * - * @param p polynomial p - * @return degree(p) - */ - - public static int Degree(int p) - { - int result = -1; - while (p != 0) - { - result++; - p = Utils.UnsignedRightBitShiftInt(p, 1); - } - return result; - } - - /** - * Return the degree of a polynomial - * - * @param p polynomial p - * @return degree(p) - */ - - public static int Degree(long p) - { - int result = 0; - while (p != 0) - { - result++; - p = Utils.UnsignedRightBitShiftLong(p, 1); - } - return result - 1; - } - - /** - * Return the remainder of a polynomial division of two polynomials. - * - * @param p dividend - * @param q divisor - * @return <tt>p mod q</tt> - */ - public static int Remainder(int p, int q) - { - int result = p; - - if (q == 0) - { - // -DM Console.Error.WriteLine - Console.Error.WriteLine("Error: to be divided by 0"); - return 0; - } - - while (Degree(result) >= Degree(q)) - { - result ^= q << (Degree(result) - Degree(q)); - } - - return result; - } - - /** - * Return the rest of devision two polynomials - * - * @param p polinomial - * @param q polinomial - * @return p mod q - */ - - public static int Rest(long p, int q) - { - long p1 = p; - if (q == 0) - { - // -DM Console.Error.WriteLine - Console.Error.WriteLine("Error: to be divided by 0"); - return 0; - } - long q1 = q & 0x00000000ffffffffL; - - while ((Utils.UnsignedRightBitShiftLong(p1, 32)) != 0) - { - p1 ^= q1 << (Degree(p1) - Degree(q1)); - } - - int result = (int)(p1 & 0xffffffff); - while (Degree(result) >= Degree(q)) - { - result ^= q << (Degree(result) - Degree(q)); - } - - return result; - } - - /** - * Return the greatest common divisor of two polynomials - * - * @param p polinomial - * @param q polinomial - * @return GCD(p, q) - */ - - public static int Gcd(int p, int q) - { - int a, b, c; - a = p; - b = q; - while (b != 0) - { - c = Remainder(a, b); - a = b; - b = c; - - } - return a; - } - - /** - * Checking polynomial for irreducibility - * - * @param p polinomial - * @return true if p is irreducible and false otherwise - */ - - public static bool IsIrreducible(int p) - { - if (p == 0) - { - return false; - } - uint tmpDeg = (uint)Degree(p); - int d = (int) tmpDeg >> 1; - int u = 2; - for (int i = 0; i < d; i++) - { - u = modMultiply(u, u, p); - if (Gcd(u ^ 2, p) != 1) - { - return false; - } - } - return true; - } - - /** - * Creates irreducible polynomial with degree d - * - * @param deg polynomial degree - * @return irreducible polynomial p - */ - public static int GetIrreduciblePolynomial(int deg) - { - if (deg < 0) - { - // -DM Console.Error.WriteLine - Console.Error.WriteLine("The Degree is negative"); - return 0; - } - if (deg > 31) - { - // -DM Console.Error.WriteLine - Console.Error.WriteLine("The Degree is more then 31"); - return 0; - } - if (deg == 0) - { - return 1; - } - int a = 1 << deg; - a++; - int b = 1 << (deg + 1); - for (int i = a; i < b; i += 2) - { - if (IsIrreducible(i)) - { - return i; - } - } - return 0; - } - } -} |