package org.bouncycastle.asn1.x9;
import java.math.BigInteger;
import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DEREncodable;
import org.bouncycastle.asn1.DERInteger;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.math.ec.ECCurve;
import org.bouncycastle.math.ec.ECPoint;
/**
* ASN.1 def for Elliptic-Curve ECParameters structure. See
* X9.62, for further details.
*/
public class X9ECParameters
implements DEREncodable, X9ObjectIdentifiers
{
private static BigInteger ONE = BigInteger.valueOf(1);
private X9FieldID fieldID;
private ECCurve curve;
private ECPoint g;
private BigInteger n;
private BigInteger h;
private byte[] seed;
public X9ECParameters(
ASN1Sequence seq)
{
if (!(seq.getObjectAt(0) instanceof DERInteger)
|| !((DERInteger)seq.getObjectAt(0)).getValue().equals(ONE))
{
throw new IllegalArgumentException("bad version in X9ECParameters");
}
X9Curve x9c = new X9Curve(
new X9FieldID((ASN1Sequence)seq.getObjectAt(1)),
(ASN1Sequence)seq.getObjectAt(2));
this.curve = x9c.getCurve();
this.g = new X9ECPoint(curve, (ASN1OctetString)seq.getObjectAt(3)).getPoint();
this.n = ((DERInteger)seq.getObjectAt(4)).getValue();
this.seed = x9c.getSeed();
if (seq.size() == 6)
{
this.h = ((DERInteger)seq.getObjectAt(5)).getValue();
}
else
{
this.h = ONE;
}
}
public X9ECParameters(
ECCurve curve,
ECPoint g,
BigInteger n)
{
this(curve, g, n, ONE, null);
}
public X9ECParameters(
ECCurve curve,
ECPoint g,
BigInteger n,
BigInteger h)
{
this(curve, g, n, h, null);
}
public X9ECParameters(
ECCurve curve,
ECPoint g,
BigInteger n,
BigInteger h,
byte[] seed)
{
this.curve = curve;
this.g = g;
this.n = n;
this.h = h;
this.seed = seed;
if (curve instanceof ECCurve.Fp)
{
this.fieldID = new X9FieldID(prime_field, ((ECCurve.Fp)curve).getQ());
}
else
{
this.fieldID = new X9FieldID(characteristic_two_field, null);
}
}
public ECCurve getCurve()
{
return curve;
}
public ECPoint getG()
{
return g;
}
public BigInteger getN()
{
return n;
}
public BigInteger getH()
{
return h;
}
public byte[] getSeed()
{
return seed;
}
/**
* Produce an object suitable for an ASN1OutputStream.
* <pre>
* ECParameters ::= SEQUENCE {
* version INTEGER { ecpVer1(1) } (ecpVer1),
* fieldID FieldID {{FieldTypes}},
* curve X9Curve,
* base X9ECPoint,
* order INTEGER,
* cofactor INTEGER OPTIONAL
* }
* </pre>
*/
public DERObject getDERObject()
{
ASN1EncodableVector v = new ASN1EncodableVector();
v.add(new DERInteger(1));
v.add(fieldID);
v.add(new X9Curve(curve, seed));
v.add(new X9ECPoint(g));
v.add(new DERInteger(n));
if (!h.equals(BigInteger.valueOf(1)))
{
v.add(new DERInteger(h));
}
return new DERSequence(v);
}
}