1 /*
   2  * Copyright (c) 2003, 2013, 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 
  26 package sun.security.rsa;
  27 
  28 import java.io.IOException;
  29 import java.math.BigInteger;
  30 
  31 import java.security.*;
  32 import java.security.interfaces.*;
  33 
  34 import sun.security.util.*;
  35 import sun.security.x509.X509Key;
  36 
  37 /**
  38  * Key implementation for RSA public keys.
  39  *
  40  * Note: RSA keys must be at least 512 bits long
  41  *
  42  * @see RSAPrivateCrtKeyImpl
  43  * @see RSAKeyFactory
  44  *
  45  * @since   1.5
  46  * @author  Andreas Sterbenz
  47  */
  48 public final class RSAPublicKeyImpl extends X509Key implements RSAPublicKey {
  49 
  50     private static final long serialVersionUID = 2644735423591199609L;
  51 
  52     private BigInteger n;       // modulus
  53     private BigInteger e;       // public exponent
  54 
  55     /**
  56      * Construct a key from its components. Used by the
  57      * RSAKeyFactory and the RSAKeyPairGenerator.
  58      */
  59     public RSAPublicKeyImpl(BigInteger n, BigInteger e)
  60             throws InvalidKeyException {
  61         this.n = n;
  62         this.e = e;
  63         RSAKeyFactory.checkRSAProviderKeyLengths(n.bitLength(), e);
  64         // generate the encoding
  65         algid = RSAPrivateCrtKeyImpl.rsaId;
  66         try {
  67             DerOutputStream out = new DerOutputStream();
  68             out.putInteger(n);
  69             out.putInteger(e);
  70             byte[] keyArray =
  71                 new DerValue(DerValue.tag_Sequence,
  72                              out.toByteArray()).toByteArray();
  73             setKey(new BitArray(keyArray.length*8, keyArray));
  74         } catch (IOException exc) {
  75             // should never occur
  76             throw new InvalidKeyException(exc);
  77         }
  78     }
  79 
  80     /**
  81      * Construct a key from its encoding. Used by RSAKeyFactory.
  82      */
  83     public RSAPublicKeyImpl(byte[] encoded) throws InvalidKeyException {
  84         decode(encoded);
  85         RSAKeyFactory.checkRSAProviderKeyLengths(n.bitLength(), e);
  86     }
  87 
  88     // see JCA doc
  89     public String getAlgorithm() {
  90         return "RSA";
  91     }
  92 
  93     // see JCA doc
  94     public BigInteger getModulus() {
  95         return n;
  96     }
  97 
  98     // see JCA doc
  99     public BigInteger getPublicExponent() {
 100         return e;
 101     }
 102 
 103     /**
 104      * Parse the key. Called by X509Key.
 105      */
 106     protected void parseKeyBits() throws InvalidKeyException {
 107         try {
 108             DerInputStream in = new DerInputStream(getKey().toByteArray());
 109             DerValue derValue = in.getDerValue();
 110             if (derValue.tag != DerValue.tag_Sequence) {
 111                 throw new IOException("Not a SEQUENCE");
 112             }
 113             DerInputStream data = derValue.data;
 114             n = RSAPrivateCrtKeyImpl.getBigInteger(data);
 115             e = RSAPrivateCrtKeyImpl.getBigInteger(data);
 116             if (derValue.data.available() != 0) {
 117                 throw new IOException("Extra data available");
 118             }
 119         } catch (IOException e) {
 120             throw new InvalidKeyException("Invalid RSA public key", e);
 121         }
 122     }
 123 
 124     // return a string representation of this key for debugging
 125     public String toString() {
 126         return "Sun RSA public key, " + n.bitLength() + " bits\n  modulus: "
 127                 + n + "\n  public exponent: " + e;
 128     }
 129 
 130     protected Object writeReplace() throws java.io.ObjectStreamException {
 131         return new KeyRep(KeyRep.Type.PUBLIC,
 132                         getAlgorithm(),
 133                         getFormat(),
 134                         getEncoded());
 135     }
 136 }