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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 java.security.spec;
import java.math.BigInteger;
/**
* The parameter specification used with Elliptic Curve Cryptography (ECC).
*/
public class ECParameterSpec implements AlgorithmParameterSpec {
// Elliptic curve for which this is parameter
private final EllipticCurve curve;
// Distinguished point on the elliptic curve called generator or base point
private final ECPoint generator;
// Order of the generator
private final BigInteger order;
// Cofactor
private final int cofactor;
// Name of curve if available.
private final String curveName;
/**
* Creates a new {@code ECParameterSpec} with the specified elliptic curve,
* the base point, the order of the generator (or base point) and the
* co-factor.
*
* @param curve
* the elliptic curve.
* @param generator
* the generator (or base point).
* @param order
* the order of the generator.
* @param cofactor
* the co-factor.
* @throws IllegalArgumentException
* if {@code order <= zero} or {@code cofactor <= zero}.
*/
public ECParameterSpec(EllipticCurve curve, ECPoint generator,
BigInteger order, int cofactor) {
this(curve, generator, order, cofactor, null);
}
/**
* Creates a new {@code ECParameterSpec} with the specified named curve
* and all of its parameters.
*
* @see #ECParameterSpec(EllipticCurve, ECPoint, BigInteger, int)
* @hide
*/
public ECParameterSpec(EllipticCurve curve, ECPoint generator,
BigInteger order, int cofactor, String curveName) {
this.curve = curve;
this.generator = generator;
this.order = order;
this.cofactor = cofactor;
this.curveName = curveName;
// throw NullPointerException if curve, generator or order is null
if (this.curve == null) {
throw new NullPointerException("curve == null");
}
if (this.generator == null) {
throw new NullPointerException("generator == null");
}
if (this.order == null) {
throw new NullPointerException("order == null");
}
// throw IllegalArgumentException if order or cofactor is not positive
if (!(this.order.compareTo(BigInteger.ZERO) > 0)) {
throw new IllegalArgumentException("order <= 0");
}
if (!(this.cofactor > 0)) {
throw new IllegalArgumentException("cofactor <= 0");
}
}
/**
* Returns the {@code cofactor}.
*
* @return the {@code cofactor}.
*/
public int getCofactor() {
return cofactor;
}
/**
* Returns the elliptic curve.
*
* @return the elliptic curve.
*/
public EllipticCurve getCurve() {
return curve;
}
/**
* Returns the generator (or base point).
*
* @return the generator (or base point).
*/
public ECPoint getGenerator() {
return generator;
}
/**
* Returns the order of the generator.
*
* @return the order of the generator.
*/
public BigInteger getOrder() {
return order;
}
/**
* Returns the name of the curve if this is a named curve. Returns
* {@code null} if this is not known to be a named curve.
*
* @hide
*/
public String getCurveName() {
return curveName;
}
}
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