org.cryptoworkshop.ximix.common.asn1.board.Pair.java Source code

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Here is the source code for org.cryptoworkshop.ximix.common.asn1.board.Pair.java

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/**
 * Copyright 2013 Crypto Workshop Pty Ltd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.cryptoworkshop.ximix.common.asn1.board;

import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DEROctetString;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.crypto.ec.ECPair;
import org.bouncycastle.math.ec.ECCurve;

/**
 * Internal class for representing a pair of EC points.
 */
class Pair extends ASN1Object {
    private final ECPair ecPair;

    Pair(ECPair ecPair) {
        this.ecPair = ecPair;
    }

    /**
     * <pre>
     *     Pair ::= SEQUENCE {
     *         x OCTET STRING,
     *         y OCTET STRING
     *     }
     * </pre>
     *
     * @return an encoding of an ASN.1 sequence
     */
    public ASN1Primitive toASN1Primitive() {
        ASN1EncodableVector v = new ASN1EncodableVector();

        v.add(new DEROctetString(ecPair.getX().getEncoded()));
        v.add(new DEROctetString(ecPair.getY().getEncoded()));

        return new DERSequence(v);
    }

    public static Pair getInstance(ECCurve curve, Object o) {
        if (o instanceof Pair) {
            return (Pair) o;
        }
        if (o != null) {
            ASN1Sequence s = ASN1Sequence.getInstance(o);

            byte[] encX = ASN1OctetString.getInstance(s.getObjectAt(0)).getOctets();
            byte[] encY = ASN1OctetString.getInstance(s.getObjectAt(1)).getOctets();

            return new Pair(new ECPair(curve.decodePoint(encX), curve.decodePoint(encY)));
        }

        return null;
    }

    public ECPair getECPair() {
        return ecPair;
    }
}