package pdftk.org.bouncycastle.crypto.agreement.jpake;

import java.io.Serializable;
import java.math.BigInteger;

/**
 * The payload sent/received during the optional third round of a J-PAKE exchange,
 * which is for explicit key confirmation.
 * <p/>
 * <p/>
 * Each {@link JPAKEParticipant} creates and sends an instance
 * of this payload to the other {@link JPAKEParticipant}.
 * The payload to send should be created via
 * {@link JPAKEParticipant#createRound3PayloadToSend(BigInteger)}
 * <p/>
 * <p/>
 * Each {@link JPAKEParticipant} must also validate the payload
 * received from the other {@link JPAKEParticipant}.
 * The received payload should be validated via
 * {@link JPAKEParticipant#validateRound3PayloadReceived(JPAKERound3Payload, BigInteger)}
 * <p/>
 * <p/>
 * This class is {@link Serializable}, so you can send it via Java serialization.
 * However, no specific mechanism for sending this payload to the other participant
 * is required.  It is perfectly safe to decompose the fields of this payload,
 * send those fields to the other participant in any format,
 * and reconstruct the payload on the other side using
 * {@link #JPAKERound3Payload(String, BigInteger)}
 */
public class JPAKERound3Payload
    implements Serializable
{
    private static final long serialVersionUID = 1L;

    /**
     * The id of the {@link JPAKEParticipant} who created/sent this payload.
     */
    private final String participantId;

    /**
     * The value of MacTag, as computed by round 3.
     *
     * @see JPAKEUtil#calculateMacTag(String, String, BigInteger, BigInteger, BigInteger, BigInteger, BigInteger, pdftk.org.bouncycastle.crypto.Digest)
     */
    private final BigInteger macTag;

    public JPAKERound3Payload(String participantId, BigInteger magTag)
    {
        this.participantId = participantId;
        this.macTag = magTag;
    }

    public String getParticipantId()
    {
        return participantId;
    }

    public BigInteger getMacTag()
    {
        return macTag;
    }

}