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.util.Objects;
  28 
  29 /**
  30  * A class representing elliptic curve private keys as defined in RFC 7748,
  31  * including the curve and other algorithm parameters. The private key is
  32  * represented as an encoded scalar value. The decoding procedure defined in
  33  * the RFC includes an operation that forces certain bits of the key to either
  34  * 1 or 0. This operation is known as "pruning" or "clamping" the private key.
  35  * All arrays in this spec are unpruned, and implementations will need to prune
  36  * the array before using it in any numerical operations.
  37  *
  38  * @since 11
  39  */
  40 public class XECPrivateKeySpec implements KeySpec {
  41 
  42     private final AlgorithmParameterSpec params;
  43     private final byte[] scalar;
  44 
  45     /**
  46      * Construct a private key spec using the supplied parameters and
  47      * encoded scalar value.
  48      *
  49      * @param params the algorithm parameters
  50      * @param scalar the unpruned encoded scalar value. This array is copied
  51      *               to protect against subsequent modification.
  52      *
  53      * @throws NullPointerException if {@code params} or {@code scalar}
  54      *                              is null.
  55      */
  56     public XECPrivateKeySpec(AlgorithmParameterSpec params, byte[] scalar) {
  57         Objects.requireNonNull(params, "params must not be null");
  58         Objects.requireNonNull(scalar, "scalar must not be null");
  59 
  60         this.params = params;
  61         this.scalar = scalar.clone();
  62     }
  63 
  64     /**
  65      * Get the algorithm parameters that define the curve and other settings.
  66      *
  67      * @return the algorithm parameters
  68      */
  69     public AlgorithmParameterSpec getParams() {
  70         return params;
  71     }
  72 
  73     /**
  74      * Get the scalar value encoded as an unpruned byte array. A new copy of
  75      * the array is returned each time this method is called.
  76      *
  77      * @return the unpruned encoded scalar value
  78      */
  79     public byte[] getScalar() {
  80         return scalar.clone();
  81     }
  82 }