1 /*
   2  * Copyright (c) 2018, 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 import java.util.Objects;
  29 
  30 /**
  31  * A class representing elliptic curve public keys as defined in RFC 7748,
  32  * including the curve and other algorithm parameters. The public key is a
  33  * particular point on the curve, which is represented using only its
  34  * u-coordinate. A u-coordinate is an element of the field of integers modulo
  35  * some value that is determined by the algorithm parameters. This field
  36  * element is represented by a BigInteger which may hold any value. That is,
  37  * the BigInteger is not restricted to the range of canonical field elements.
  38  *
  39  * @since 11
  40  */
  41 public class XECPublicKeySpec implements KeySpec {
  42 
  43     private final AlgorithmParameterSpec params;
  44     private final BigInteger u;
  45 
  46     /**
  47      * Construct a public key spec using the supplied parameters and
  48      * u coordinate.
  49      *
  50      * @param params the algorithm parameters
  51      * @param u the u-coordinate of the point, represented using a BigInteger
  52      *          which may hold any value
  53      *
  54      * @throws NullPointerException if {@code params} or {@code u}
  55      *                              is null.
  56      */
  57     public XECPublicKeySpec(AlgorithmParameterSpec params, BigInteger u) {
  58         Objects.requireNonNull(params, "params must not be null");
  59         Objects.requireNonNull(u, "u must not be null");
  60 
  61         this.params = params;
  62         this.u = u;
  63     }
  64 
  65     /**
  66      * Get the algorithm parameters that define the curve and other settings.
  67      *
  68      * @return the parameters
  69      */
  70     public AlgorithmParameterSpec getParams() {
  71         return params;
  72     }
  73 
  74     /**
  75      * Get the u coordinate of the point.
  76      *
  77      * @return the u-coordinate, represented using a BigInteger which may hold
  78      *          any value
  79      */
  80     public BigInteger getU() {
  81         return u;
  82     }
  83 }