http://www.bouncycastle.org/java.html: 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 JDK 1.5 to JDK 1.8.
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package org.bouncycastle.asn1.cryptopro;

import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1TaggedObject;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.asn1.DERTaggedObject;


    GostR3410-KeyTransport ::= SEQUENCE {
      sessionEncryptedKey   Gost28147-89-EncryptedKey,
      transportParameters
         [0] IMPLICIT GostR3410-TransportParameters OPTIONAL
   }



/**
 * <pre>
 *     GostR3410-KeyTransport ::= SEQUENCE {
 *       sessionEncryptedKey   Gost28147-89-EncryptedKey,
 *       transportParameters
 *          [0] IMPLICIT GostR3410-TransportParameters OPTIONAL
 *    }
 * </pre>
 */
public class GostR3410KeyTransport
    extends ASN1Object
{
    private final Gost2814789EncryptedKey sessionEncryptedKey;
    private final GostR3410TransportParameters transportParameters;

    private GostR3410KeyTransport(ASN1Sequence seq)
    {
       this.sessionEncryptedKey = Gost2814789EncryptedKey.getInstance(seq.getObjectAt(0));
       this.transportParameters = GostR3410TransportParameters.getInstance(ASN1TaggedObject.getInstance(seq.getObjectAt(1)), false);
    }

    public GostR3410KeyTransport(Gost2814789EncryptedKey sessionEncryptedKey, GostR3410TransportParameters transportParameters)
    {
        this.sessionEncryptedKey = sessionEncryptedKey;
        this.transportParameters = transportParameters;
    }

    public static GostR3410KeyTransport getInstance(
        Object obj)
    {
        if (obj instanceof GostR3410KeyTransport)
        {
            return (GostR3410KeyTransport)obj;
        }

        if (obj != null)
        {
            return new GostR3410KeyTransport(ASN1Sequence.getInstance(obj));
        }

        return null;
    }

    public Gost2814789EncryptedKey getSessionEncryptedKey()
    {
        return sessionEncryptedKey;
    }

    public GostR3410TransportParameters getTransportParameters()
    {
        return transportParameters;
    }

    public ASN1Primitive toASN1Primitive()
    {
        ASN1EncodableVector v = new ASN1EncodableVector();

        v.add(sessionEncryptedKey);
        if (transportParameters != null)
        {
            v.add(new DERTaggedObject(false, 0, transportParameters));
        }

        return new DERSequence(v);
    }
}