1 /*
2 * Copyright (c) 2009, 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.ec;
27
28 import java.math.BigInteger;
29 import java.security.*;
30 import java.security.spec.AlgorithmParameterSpec;
31 import java.security.spec.ECGenParameterSpec;
32 import java.security.spec.ECParameterSpec;
33 import java.security.spec.ECPoint;
34
35 import sun.security.ec.NamedCurve;
36 import sun.security.ec.ECParameters;
37 import sun.security.ec.ECPrivateKeyImpl;
38 import sun.security.ec.ECPublicKeyImpl;
39 import sun.security.jca.JCAUtil;
40 import sun.security.util.ECUtil;
41
42 /**
43 * EC keypair generator.
44 * Standard algorithm, minimum key length is 112 bits, maximum is 571 bits.
45 *
46 * @since 1.7
47 */
48 public final class ECKeyPairGenerator extends KeyPairGeneratorSpi {
49
50 private static final int KEY_SIZE_MIN = 112; // min bits (see ecc_impl.h)
51 private static final int KEY_SIZE_MAX = 571; // max bits (see ecc_impl.h)
52 private static final int KEY_SIZE_DEFAULT = 256;
53
54 // used to seed the keypair generator
55 private SecureRandom random;
56
57 // size of the key to generate, KEY_SIZE_MIN <= keySize <= KEY_SIZE_MAX
58 private int keySize;
59
60 // parameters specified via init, if any
61 private AlgorithmParameterSpec params = null;
62
63 /**
64 * Constructs a new ECKeyPairGenerator.
65 */
66 public ECKeyPairGenerator() {
67 // initialize to default in case the app does not call initialize()
68 initialize(KEY_SIZE_DEFAULT, null);
69 }
70
71 // initialize the generator. See JCA doc
72 @Override
73 public void initialize(int keySize, SecureRandom random) {
74
75 checkKeySize(keySize);
76 this.params = ECUtil.getECParameterSpec(null, keySize);
77 if (params == null) {
78 throw new InvalidParameterException(
79 "No EC parameters available for key size " + keySize + " bits");
80 }
81 this.random = random;
82 }
83
84 // second initialize method. See JCA doc
85 @Override
86 public void initialize(AlgorithmParameterSpec params, SecureRandom random)
87 throws InvalidAlgorithmParameterException {
88
89 if (params instanceof ECParameterSpec) {
90 this.params = ECUtil.getECParameterSpec(null,
91 (ECParameterSpec)params);
92 if (this.params == null) {
93 throw new InvalidAlgorithmParameterException(
94 "Unsupported curve: " + params);
95 }
96 } else if (params instanceof ECGenParameterSpec) {
97 String name = ((ECGenParameterSpec)params).getName();
98 this.params = ECUtil.getECParameterSpec(null, name);
99 if (this.params == null) {
100 throw new InvalidAlgorithmParameterException(
101 "Unknown curve name: " + name);
102 }
103 } else {
104 throw new InvalidAlgorithmParameterException(
105 "ECParameterSpec or ECGenParameterSpec required for EC");
106 }
107 this.keySize =
108 ((ECParameterSpec)this.params).getCurve().getField().getFieldSize();
109 this.random = random;
110 }
111
112 // generate the keypair. See JCA doc
113 @Override
114 public KeyPair generateKeyPair() {
115
116 byte[] encodedParams =
117 ECUtil.encodeECParameterSpec(null, (ECParameterSpec)params);
118
119 // seed is twice the key size (in bytes) plus 1
120 byte[] seed = new byte[(((keySize + 7) >> 3) + 1) * 2];
121 if (random == null) {
122 random = JCAUtil.getSecureRandom();
123 }
124 random.nextBytes(seed);
125
126 try {
127
128 long[] handles = generateECKeyPair(keySize, encodedParams, seed);
129
130 // The 'params' object supplied above is equivalent to the native
131 // one so there is no need to fetch it.
132
133 // handles[0] points to the native private key
134 BigInteger s = new BigInteger(1, getEncodedBytes(handles[0]));
135
136 PrivateKey privateKey =
137 new ECPrivateKeyImpl(s, (ECParameterSpec)params);
138
139 // handles[1] points to the native public key
140 ECPoint w = ECUtil.decodePoint(getEncodedBytes(handles[1]),
141 ((ECParameterSpec)params).getCurve());
142 PublicKey publicKey =
143 new ECPublicKeyImpl(w, (ECParameterSpec)params);
144
145 return new KeyPair(publicKey, privateKey);
146
147 } catch (Exception e) {
148 throw new ProviderException(e);
149 }
150 }
151
152 private void checkKeySize(int keySize) throws InvalidParameterException {
153 if (keySize < KEY_SIZE_MIN) {
154 throw new InvalidParameterException
155 ("Key size must be at least " + KEY_SIZE_MIN + " bits");
156 }
157 if (keySize > KEY_SIZE_MAX) {
158 throw new InvalidParameterException
159 ("Key size must be at most " + KEY_SIZE_MAX + " bits");
160 }
161 this.keySize = keySize;
162 }
163
164 /*
165 * Generates the keypair and returns a 2-element array of handles.
166 * The first handle points to the private key, the second to the public key.
167 */
168 private static native long[] generateECKeyPair(int keySize,
169 byte[] encodedParams, byte[] seed) throws GeneralSecurityException;
170
171 /*
172 * Extracts the encoded key data using the supplied handle.
173 */
174 private static native byte[] getEncodedBytes(long handle);
175 }