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The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. This jar contains APIs for JDK 1.5 and up. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs.

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package org.bouncycastle.math.ec.custom.sec;

import java.math.BigInteger;

import org.bouncycastle.math.ec.AbstractECLookupTable;
import org.bouncycastle.math.ec.ECConstants;
import org.bouncycastle.math.ec.ECCurve;
import org.bouncycastle.math.ec.ECCurve.AbstractF2m;
import org.bouncycastle.math.ec.ECFieldElement;
import org.bouncycastle.math.ec.ECLookupTable;
import org.bouncycastle.math.ec.ECPoint;
import org.bouncycastle.math.raw.Nat192;
import org.bouncycastle.util.encoders.Hex;

public class SecT163R1Curve extends AbstractF2m
{
    private static final int SECT163R1_DEFAULT_COORDS = COORD_LAMBDA_PROJECTIVE;
    private static final ECFieldElement[] SECT163R1_AFFINE_ZS = new ECFieldElement[] { new SecT163FieldElement(ECConstants.ONE) }; 

    protected SecT163R1Point infinity;

    public SecT163R1Curve()
    {
        super(163, 3, 6, 7);

        this.infinity = new SecT163R1Point(this, null, null);

        this.a = fromBigInteger(new BigInteger(1, Hex.decodeStrict("07B6882CAAEFA84F9554FF8428BD88E246D2782AE2")));
        this.b = fromBigInteger(new BigInteger(1, Hex.decodeStrict("0713612DCDDCB40AAB946BDA29CA91F73AF958AFD9")));
        this.order = new BigInteger(1, Hex.decodeStrict("03FFFFFFFFFFFFFFFFFFFF48AAB689C29CA710279B"));
        this.cofactor = BigInteger.valueOf(2);

        this.coord = SECT163R1_DEFAULT_COORDS;
    }

    protected ECCurve cloneCurve()
    {
        return new SecT163R1Curve();
    }

    public boolean supportsCoordinateSystem(int coord)
    {
        switch (coord)
        {
        case COORD_LAMBDA_PROJECTIVE:
            return true;
        default:
            return false;
        }
    }

    public int getFieldSize()
    {
        return 163;
    }

    public ECFieldElement fromBigInteger(BigInteger x)
    {
        return new SecT163FieldElement(x);
    }

    protected ECPoint createRawPoint(ECFieldElement x, ECFieldElement y)
    {
        return new SecT163R1Point(this, x, y);
    }

    protected ECPoint createRawPoint(ECFieldElement x, ECFieldElement y, ECFieldElement[] zs)
    {
        return new SecT163R1Point(this, x, y, zs);
    }

    public ECPoint getInfinity()
    {
        return infinity;
    }

    public boolean isKoblitz()
    {
        return false;
    }

    public int getM()
    {
        return 163;
    }

    public boolean isTrinomial()
    {
        return false;
    }

    public int getK1()
    {
        return 3;
    }

    public int getK2()
    {
        return 6;
    }

    public int getK3()
    {
        return 7;
    }

    public ECLookupTable createCacheSafeLookupTable(ECPoint[] points, int off, final int len)
    {
        final int FE_LONGS = 3;

        final long[] table = new long[len * FE_LONGS * 2];
        {
            int pos = 0;
            for (int i = 0; i < len; ++i)
            {
                ECPoint p = points[off + i];
                Nat192.copy64(((SecT163FieldElement)p.getRawXCoord()).x, 0, table, pos); pos += FE_LONGS;
                Nat192.copy64(((SecT163FieldElement)p.getRawYCoord()).x, 0, table, pos); pos += FE_LONGS;
            }
        }

        return new AbstractECLookupTable()
        {
            public int getSize()
            {
                return len;
            }

            public ECPoint lookup(int index)
            {
                long[] x = Nat192.create64(), y = Nat192.create64();
                int pos = 0;

                for (int i = 0; i < len; ++i)
                {
                    long MASK = ((i ^ index) - 1) >> 31;

                    for (int j = 0; j < FE_LONGS; ++j)
                    {
                        x[j] ^= table[pos + j] & MASK;
                        y[j] ^= table[pos + FE_LONGS + j] & MASK;
                    }

                    pos += (FE_LONGS * 2);
                }

                return createPoint(x, y);
            }

            public ECPoint lookupVar(int index)
            {
                long[] x = Nat192.create64(), y = Nat192.create64();
                int pos = index * FE_LONGS * 2;

                for (int j = 0; j < FE_LONGS; ++j)
                {
                    x[j] = table[pos + j];
                    y[j] = table[pos + FE_LONGS + j];
                }

                return createPoint(x, y);
            }

            private ECPoint createPoint(long[] x, long[] y)
            {
                return createRawPoint(new SecT163FieldElement(x), new SecT163FieldElement(y), SECT163R1_AFFINE_ZS);
            }
        };
    }
}