1 /* 2 * Copyright (c) 2003, 2017, 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 private static final BigInteger THREE = BigInteger.valueOf(3); 52 53 private BigInteger n; // modulus 54 private BigInteger e; // public exponent 55 56 /** 57 * Construct a key from its components. Used by the 58 * RSAKeyFactory and the RSAKeyPairGenerator. 59 */ 60 public RSAPublicKeyImpl(BigInteger n, BigInteger e) 61 throws InvalidKeyException { 62 this.n = n; 63 this.e = e; 64 RSAKeyFactory.checkRSAProviderKeyLengths(n.bitLength(), e); 65 checkExponentRange(); 66 // generate the encoding 67 algid = RSAPrivateCrtKeyImpl.rsaId; 68 try { 69 DerOutputStream out = new DerOutputStream(); 70 out.putInteger(n); 71 out.putInteger(e); 72 byte[] keyArray = 73 new DerValue(DerValue.tag_Sequence, 74 out.toByteArray()).toByteArray(); 75 setKey(new BitArray(keyArray.length*8, keyArray)); 76 } catch (IOException exc) { 77 // should never occur 78 throw new InvalidKeyException(exc); 79 } 80 } 81 82 /** 83 * Construct a key from its encoding. Used by RSAKeyFactory. 84 */ 85 public RSAPublicKeyImpl(byte[] encoded) throws InvalidKeyException { 86 decode(encoded); 87 RSAKeyFactory.checkRSAProviderKeyLengths(n.bitLength(), e); 88 checkExponentRange(); 89 } 90 91 private void checkExponentRange() throws InvalidKeyException { 92 // the exponent should be smaller than the modulus 93 if (e.compareTo(n) >= 0) { 94 throw new InvalidKeyException("exponent is larger than modulus"); 95 } 96 97 // the exponent should be at least 3 98 if (e.compareTo(THREE) < 0) { 99 throw new InvalidKeyException("exponent is smaller than 3"); 100 } 101 } 102 103 // see JCA doc 104 public String getAlgorithm() { 105 return "RSA"; 106 } 107 108 // see JCA doc 109 public BigInteger getModulus() { 110 return n; 111 } 112 113 // see JCA doc 114 public BigInteger getPublicExponent() { 115 return e; 116 } 117 118 /** 119 * Parse the key. Called by X509Key. 120 */ 121 protected void parseKeyBits() throws InvalidKeyException { 122 try { 123 DerInputStream in = new DerInputStream(getKey().toByteArray()); 124 DerValue derValue = in.getDerValue(); 125 if (derValue.tag != DerValue.tag_Sequence) { 126 throw new IOException("Not a SEQUENCE"); 127 } 128 DerInputStream data = derValue.data; 129 n = data.getPositiveBigInteger(); 130 e = data.getPositiveBigInteger(); 131 if (derValue.data.available() != 0) { 132 throw new IOException("Extra data available"); 133 } 134 } catch (IOException e) { 135 throw new InvalidKeyException("Invalid RSA public key", e); 136 } 137 } 138 139 // return a string representation of this key for debugging 140 public String toString() { 141 return "Sun RSA public key, " + n.bitLength() + " bits\n modulus: " 142 + n + "\n public exponent: " + e; 143 } 144 145 protected Object writeReplace() throws java.io.ObjectStreamException { 146 return new KeyRep(KeyRep.Type.PUBLIC, 147 getAlgorithm(), 148 getFormat(), 149 getEncoded()); 150 } 151 }