org.bouncycastle.math.ec.custom.sec.SecP224K1Field Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of bcprov-ext-debug-jdk18on Show documentation
The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for Java 1.8 and later with debug enabled.
The newest version!
package org.bouncycastle.math.ec.custom.sec;

import java.math.BigInteger;
import java.security.SecureRandom;

import org.bouncycastle.math.raw.Mod;
import org.bouncycastle.math.raw.Nat;
import org.bouncycastle.math.raw.Nat224;
import org.bouncycastle.util.Pack;

public class SecP224K1Field
{
    // 2^224 - 2^32 - 2^12 - 2^11 - 2^9 - 2^7 - 2^4 - 2 - 1
    static final int[] P = new int[]{ 0xFFFFE56D, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF,
        0xFFFFFFFF };
    private static final int[] PExt = new int[]{ 0x02C23069, 0x00003526, 0x00000001, 0x00000000, 0x00000000, 0x00000000,
        0x00000000, 0xFFFFCADA, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
    private static final int[] PExtInv = new int[]{ 0xFD3DCF97, 0xFFFFCAD9, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF,
        0xFFFFFFFF, 0xFFFFFFFF, 0x00003525, 0x00000002 };
    private static final int P6 = 0xFFFFFFFF;
    private static final int PExt13 = 0xFFFFFFFF;
    private static final int PInv33 = 0x1A93;

    public static void add(int[] x, int[] y, int[] z)
    {
        int c = Nat224.add(x, y, z);
        if (c != 0 || (z[6] == P6 && Nat224.gte(z, P)))
        {
            Nat.add33To(7, PInv33, z);
        }
    }

    public static void addExt(int[] xx, int[] yy, int[] zz)
    {
        int c = Nat.add(14, xx, yy, zz);
        if (c != 0 || (zz[13] == PExt13 && Nat.gte(14, zz, PExt)))
        {
            if (Nat.addTo(PExtInv.length, PExtInv, zz) != 0)
            {
                Nat.incAt(14, zz, PExtInv.length);
            }
        }
    }

    public static void addOne(int[] x, int[] z)
    {
        int c = Nat.inc(7, x, z);
        if (c != 0 || (z[6] == P6 && Nat224.gte(z, P)))
        {
            Nat.add33To(7, PInv33, z);
        }
    }

    public static int[] fromBigInteger(BigInteger x)
    {
        int[] z = Nat224.fromBigInteger(x);
        if (z[6] == P6 && Nat224.gte(z, P))
        {
            Nat.add33To(7, PInv33, z);
        }
        return z;
    }

    public static void half(int[] x, int[] z)
    {
        if ((x[0] & 1) == 0)
        {
            Nat.shiftDownBit(7, x, 0, z);
        }
        else
        {
            int c = Nat224.add(x, P, z);
            Nat.shiftDownBit(7, z, c);
        }
    }

    public static void inv(int[] x, int[] z)
    {
        Mod.checkedModOddInverse(P, x, z);
    }

    public static int isZero(int[] x)
    {
        int d = 0;
        for (int i = 0; i < 7; ++i)
        {
            d |= x[i];
        }
        d = (d >>> 1) | (d & 1);
        return (d - 1) >> 31;
    }

    public static void multiply(int[] x, int[] y, int[] z)
    {
        int[] tt = Nat224.createExt();
        Nat224.mul(x, y, tt);
        reduce(tt, z);
    }

    public static void multiplyAddToExt(int[] x, int[] y, int[] zz)
    {
        int c = Nat224.mulAddTo(x, y, zz);
        if (c != 0 || (zz[13] == PExt13 && Nat.gte(14, zz, PExt)))
        {
            if (Nat.addTo(PExtInv.length, PExtInv, zz) != 0)
            {
                Nat.incAt(14, zz, PExtInv.length);
            }
        }
    }

    public static void negate(int[] x, int[] z)
    {
        if (0 != isZero(x))
        {
            Nat224.sub(P, P, z);
        }
        else
        {
            Nat224.sub(P, x, z);
        }
    }

    public static void random(SecureRandom r, int[] z)
    {
        byte[] bb = new byte[7 * 4];
        do
        {
            r.nextBytes(bb);
            Pack.littleEndianToInt(bb, 0, z, 0, 7);
        }
        while (0 == Nat.lessThan(7, z, P));
    }

    public static void randomMult(SecureRandom r, int[] z)
    {
        do
        {
            random(r, z);
        }
        while (0 != isZero(z));
    }

    public static void reduce(int[] xx, int[] z)
    {
        long cc = Nat224.mul33Add(PInv33, xx, 7, xx, 0, z, 0);
        int c = Nat224.mul33DWordAdd(PInv33, cc, z, 0);

        // assert c == 0L || c == 1L;

        if (c != 0 || (z[6] == P6 && Nat224.gte(z, P)))
        {
            Nat.add33To(7, PInv33, z);
        }
    }

    public static void reduce32(int x, int[] z)
    {
        if ((x != 0 && Nat224.mul33WordAdd(PInv33, x, z, 0) != 0)
            || (z[6] == P6 && Nat224.gte(z, P)))
        {
            Nat.add33To(7, PInv33, z);
        }
    }

    public static void square(int[] x, int[] z)
    {
        int[] tt = Nat224.createExt();
        Nat224.square(x, tt);
        reduce(tt, z);
    }

    public static void squareN(int[] x, int n, int[] z)
    {
//        assert n > 0;

        int[] tt = Nat224.createExt();
        Nat224.square(x, tt);
        reduce(tt, z);

        while (--n > 0)
        {
            Nat224.square(z, tt);
            reduce(tt, z);
        }
    }

    public static void subtract(int[] x, int[] y, int[] z)
    {
        int c = Nat224.sub(x, y, z);
        if (c != 0)
        {
            Nat.sub33From(7, PInv33, z);
        }
    }

    public static void subtractExt(int[] xx, int[] yy, int[] zz)
    {
        int c = Nat.sub(14, xx, yy, zz);
        if (c != 0)
        {
            if (Nat.subFrom(PExtInv.length, PExtInv, zz) != 0)
            {
                Nat.decAt(14, zz, PExtInv.length);
            }
        }
    }

    public static void twice(int[] x, int[] z)
    {
        int c = Nat.shiftUpBit(7, x, 0, z);
        if (c != 0 || (z[6] == P6 && Nat224.gte(z, P)))
        {
            Nat.add33To(7, PInv33, z);
        }
    }
}