org.bouncycastle.math.raw.Nat320 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.raw;

import java.math.BigInteger;

import org.bouncycastle.util.Pack;

public abstract class Nat320
{
    public static void copy64(long[] x, long[] z)
    {
        z[0] = x[0];
        z[1] = x[1];
        z[2] = x[2];
        z[3] = x[3];
        z[4] = x[4];
    }

    public static void copy64(long[] x, int xOff, long[] z, int zOff)
    {
        z[zOff + 0] = x[xOff + 0];
        z[zOff + 1] = x[xOff + 1];
        z[zOff + 2] = x[xOff + 2];
        z[zOff + 3] = x[xOff + 3];
        z[zOff + 4] = x[xOff + 4];
    }

    public static long[] create64()
    {
        return new long[5];
    }

    public static long[] createExt64()
    {
        return new long[10];
    }

    public static boolean eq64(long[] x, long[] y)
    {
        for (int i = 4; i >= 0; --i)
        {
            if (x[i] != y[i])
            {
                return false;
            }
        }
        return true;
    }

    public static long[] fromBigInteger64(BigInteger x)
    {
        if (x.signum() < 0 || x.bitLength() > 320)
        {
            throw new IllegalArgumentException();
        }

        long[] z = create64();

        // NOTE: Use a fixed number of loop iterations
        for (int i = 0; i < 5; ++i)
        {
            z[i] = x.longValue();
            x = x.shiftRight(64);
        }
        return z;
    }

    public static boolean isOne64(long[] x)
    {
        if (x[0] != 1L)
        {
            return false;
        }
        for (int i = 1; i < 5; ++i)
        {
            if (x[i] != 0L)
            {
                return false;
            }
        }
        return true;
    }

    public static boolean isZero64(long[] x)
    {
        for (int i = 0; i < 5; ++i)
        {
            if (x[i] != 0L)
            {
                return false;
            }
        }
        return true;
    }

    public static BigInteger toBigInteger64(long[] x)
    {
        byte[] bs = new byte[40];
        for (int i = 0; i < 5; ++i)
        {
            long x_i = x[i];
            if (x_i != 0L)
            {
                Pack.longToBigEndian(x_i, bs, (4 - i) << 3);
            }
        }
        return new BigInteger(1, bs);
    }
}