nl.open.jwtdependency.org.bouncycastle.math.raw.Mont256 Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of java-jwt-nodependencies Show documentation

This is a drop in replacement for the auth0 java-jwt library (see https://github.com/auth0/java-jwt). This jar makes sure there are no external dependencies (e.g. fasterXml, Apacha Commons) needed. This is useful when deploying to an application server (e.g. tomcat with Alfreso or Pega).

The newest version!

package org.bouncycastle.math.raw;

public abstract class Mont256
{
    private static final long M = 0xFFFFFFFFL;

    public static int inverse32(int x)
    {
        // assert (x & 1) == 1;
        int z = x; // x.z == 1 mod 2**3
        z *= 2 - x * z; // x.z == 1 mod 2**6
        z *= 2 - x * z; // x.z == 1 mod 2**12
        z *= 2 - x * z; // x.z == 1 mod 2**24
        z *= 2 - x * z; // x.z == 1 mod 2**48
        // assert x * z == 1;
        return z;
    }

    public static void multAdd(int[] x, int[] y, int[] z, int[] m, int mInv32)
    {
        int z_8 = 0;
        long y_0 = y[0] & M;

        for (int i = 0; i < 8; ++i)
        {
            long z_0 = z[0] & M;
            long x_i = x[i] & M;

            long prod1 = x_i * y_0;
            long carry = (prod1 & M) + z_0;

            long t = ((int)carry * mInv32) & M;

            long prod2 = t * (m[0] & M);
            carry += (prod2 & M);
            // assert (int)carry == 0;
            carry = (carry >>> 32) + (prod1 >>> 32) + (prod2 >>> 32);

            for (int j = 1; j < 8; ++j)
            {
                prod1 = x_i * (y[j] & M);
                prod2 = t * (m[j] & M);

                carry += (prod1 & M) + (prod2 & M) + (z[j] & M);
                z[j - 1] = (int)carry;
                carry = (carry >>> 32) + (prod1 >>> 32) + (prod2 >>> 32);
            }

            carry += (z_8 & M);
            z[7] = (int)carry;
            z_8 = (int)(carry >>> 32);
        }

        if (z_8 != 0 || Nat256.gte(z, m))
        {
            Nat256.sub(z, m, z);
        }
    }

    public static void multAddXF(int[] x, int[] y, int[] z, int[] m)
    {
        // assert m[0] == M;

        int z_8 = 0;
        long y_0 = y[0] & M;

        for (int i = 0; i < 8; ++i)
        {
            long x_i = x[i] & M;

            long carry = x_i * y_0 + (z[0] & M);
            long t = carry & M;
            carry = (carry >>> 32) + t;

            for (int j = 1; j < 8; ++j)
            {
                long prod1 = x_i * (y[j] & M);
                long prod2 = t * (m[j] & M);

                carry += (prod1 & M) + (prod2 & M) + (z[j] & M);
                z[j - 1] = (int)carry;
                carry = (carry >>> 32) + (prod1 >>> 32) + (prod2 >>> 32);
            }

            carry += (z_8 & M);
            z[7] = (int)carry;
            z_8 = (int)(carry >>> 32);
        }

        if (z_8 != 0 || Nat256.gte(z, m))
        {
            Nat256.sub(z, m, z);
        }
    }

    public static void reduce(int[] z, int[] m, int mInv32)
    {
        for (int i = 0; i < 8; ++i)
        {
            int z_0 = z[0];

            long t = (z_0 * mInv32) & M;

            long carry = t * (m[0] & M) + (z_0 & M);
            // assert (int)carry == 0;
            carry >>>= 32;

            for (int j = 1; j < 8; ++j)
            {
                carry += t * (m[j] & M) + (z[j] & M);
                z[j - 1] = (int)carry;
                carry >>>= 32;
            }

            z[7] = (int)carry;
            // assert carry >>> 32 == 0;
        }

        if (Nat256.gte(z, m))
        {
            Nat256.sub(z, m, z);
        }
    }

    public static void reduceXF(int[] z, int[] m)
    {
        // assert m[0] == M;

        for (int i = 0; i < 8; ++i)
        {
            int z_0 = z[0];

            long t = z_0 & M;
            long carry = t;

            for (int j = 1; j < 8; ++j)
            {
                carry += t * (m[j] & M) + (z[j] & M);
                z[j - 1] = (int)carry;
                carry >>>= 32;
            }

            z[7] = (int)carry;
            // assert carry >>> 32 == 0;
        }

        if (Nat256.gte(z, m))
        {
            Nat256.sub(z, m, z);
        }
    }
}