1 /* 2 * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package java.security.spec; 26 27 import java.math.BigInteger; 28 29 /** 30 * This immutable class specifies the set of domain parameters 31 * used with elliptic curve cryptography (ECC). 32 * 33 * @see AlgorithmParameterSpec 34 * 35 * @author Valerie Peng 36 * 37 * @since 1.5 38 */ 39 public class ECParameterSpec implements AlgorithmParameterSpec { 40 41 private final EllipticCurve curve; 42 private final ECPoint g; 43 private final BigInteger n; 44 private final int h; 45 46 /** 47 * Creates elliptic curve domain parameters based on the 48 * specified values. 49 * @param curve the elliptic curve which this parameter 50 * defines. 51 * @param g the generator which is also known as the base point. 52 * @param n the order of the generator <code>g</code>. 53 * @param h the cofactor. 54 * @exception NullPointerException if <code>curve</code>, 55 * <code>g</code>, or <code>n</code> is null. 56 * @exception IllegalArgumentException if <code>n</code> 57 * or <code>h</code> is not positive. 58 */ 59 public ECParameterSpec(EllipticCurve curve, ECPoint g, 60 BigInteger n, int h) { 61 if (curve == null) { 62 throw new NullPointerException("curve is null"); 63 } 64 if (g == null) { 65 throw new NullPointerException("g is null"); 66 } 67 if (n == null) { 68 throw new NullPointerException("n is null"); 69 } 70 if (n.signum() != 1) { 71 throw new IllegalArgumentException("n is not positive"); 72 } 73 if (h <= 0) { 74 throw new IllegalArgumentException("h is not positive"); 75 } 76 this.curve = curve; 77 this.g = g; 78 this.n = n; 79 this.h = h; 80 } 81 82 /** 83 * Returns the elliptic curve that this parameter defines. 84 * @return the elliptic curve that this parameter defines. 85 */ 86 public EllipticCurve getCurve() { 87 return curve; 88 } 89 90 /** 91 * Returns the generator which is also known as the base point. 92 * @return the generator which is also known as the base point. 93 */ 94 public ECPoint getGenerator() { 95 return g; 96 } 97 98 /** 99 * Returns the order of the generator. 100 * @return the order of the generator. 101 */ 102 public BigInteger getOrder() { 103 return n; 104 } 105 106 /** 107 * Returns the cofactor. 108 * @return the cofactor. 109 */ 110 public int getCofactor() { 111 return h; 112 } 113 }