Piotr Jastrzebski | 51b1b69 | 2015-02-16 15:01:09 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 1997, 2007, 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 javax.crypto; |
| 27 | |
| 28 | import java.security.*; |
| 29 | import java.security.spec.*; |
| 30 | |
| 31 | /** |
| 32 | * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>) |
| 33 | * for the <code>KeyAgreement</code> class. |
| 34 | * All the abstract methods in this class must be implemented by each |
| 35 | * cryptographic service provider who wishes to supply the implementation |
| 36 | * of a particular key agreement algorithm. |
| 37 | * |
| 38 | * <p> The keys involved in establishing a shared secret are created by one |
| 39 | * of the |
| 40 | * key generators (<code>KeyPairGenerator</code> or |
| 41 | * <code>KeyGenerator</code>), a <code>KeyFactory</code>, or as a result from |
| 42 | * an intermediate phase of the key agreement protocol |
| 43 | * ({@link #engineDoPhase(java.security.Key, boolean) engineDoPhase}). |
| 44 | * |
| 45 | * <p> For each of the correspondents in the key exchange, |
| 46 | * <code>engineDoPhase</code> |
| 47 | * needs to be called. For example, if the key exchange is with one other |
| 48 | * party, <code>engineDoPhase</code> needs to be called once, with the |
| 49 | * <code>lastPhase</code> flag set to <code>true</code>. |
| 50 | * If the key exchange is |
| 51 | * with two other parties, <code>engineDoPhase</code> needs to be called twice, |
| 52 | * the first time setting the <code>lastPhase</code> flag to |
| 53 | * <code>false</code>, and the second time setting it to <code>true</code>. |
| 54 | * There may be any number of parties involved in a key exchange. |
| 55 | * |
| 56 | * @author Jan Luehe |
| 57 | * |
| 58 | * @see KeyGenerator |
| 59 | * @see SecretKey |
| 60 | * @since 1.4 |
| 61 | */ |
| 62 | |
| 63 | public abstract class KeyAgreementSpi { |
| 64 | |
| 65 | /** |
| 66 | * Initializes this key agreement with the given key and source of |
| 67 | * randomness. The given key is required to contain all the algorithm |
| 68 | * parameters required for this key agreement. |
| 69 | * |
| 70 | * <p> If the key agreement algorithm requires random bytes, it gets them |
| 71 | * from the given source of randomness, <code>random</code>. |
| 72 | * However, if the underlying |
| 73 | * algorithm implementation does not require any random bytes, |
| 74 | * <code>random</code> is ignored. |
| 75 | * |
| 76 | * @param key the party's private information. For example, in the case |
| 77 | * of the Diffie-Hellman key agreement, this would be the party's own |
| 78 | * Diffie-Hellman private key. |
| 79 | * @param random the source of randomness |
| 80 | * |
| 81 | * @exception InvalidKeyException if the given key is |
| 82 | * inappropriate for this key agreement, e.g., is of the wrong type or |
| 83 | * has an incompatible algorithm type. |
| 84 | */ |
| 85 | protected abstract void engineInit(Key key, SecureRandom random) |
| 86 | throws InvalidKeyException; |
| 87 | |
| 88 | /** |
| 89 | * Initializes this key agreement with the given key, set of |
| 90 | * algorithm parameters, and source of randomness. |
| 91 | * |
| 92 | * @param key the party's private information. For example, in the case |
| 93 | * of the Diffie-Hellman key agreement, this would be the party's own |
| 94 | * Diffie-Hellman private key. |
| 95 | * @param params the key agreement parameters |
| 96 | * @param random the source of randomness |
| 97 | * |
| 98 | * @exception InvalidKeyException if the given key is |
| 99 | * inappropriate for this key agreement, e.g., is of the wrong type or |
| 100 | * has an incompatible algorithm type. |
| 101 | * @exception InvalidAlgorithmParameterException if the given parameters |
| 102 | * are inappropriate for this key agreement. |
| 103 | */ |
| 104 | protected abstract void engineInit(Key key, AlgorithmParameterSpec params, |
| 105 | SecureRandom random) |
| 106 | throws InvalidKeyException, InvalidAlgorithmParameterException; |
| 107 | |
| 108 | /** |
| 109 | * Executes the next phase of this key agreement with the given |
| 110 | * key that was received from one of the other parties involved in this key |
| 111 | * agreement. |
| 112 | * |
| 113 | * @param key the key for this phase. For example, in the case of |
| 114 | * Diffie-Hellman between 2 parties, this would be the other party's |
| 115 | * Diffie-Hellman public key. |
| 116 | * @param lastPhase flag which indicates whether or not this is the last |
| 117 | * phase of this key agreement. |
| 118 | * |
| 119 | * @return the (intermediate) key resulting from this phase, or null if |
| 120 | * this phase does not yield a key |
| 121 | * |
| 122 | * @exception InvalidKeyException if the given key is inappropriate for |
| 123 | * this phase. |
| 124 | * @exception IllegalStateException if this key agreement has not been |
| 125 | * initialized. |
| 126 | */ |
| 127 | protected abstract Key engineDoPhase(Key key, boolean lastPhase) |
| 128 | throws InvalidKeyException, IllegalStateException; |
| 129 | |
| 130 | /** |
| 131 | * Generates the shared secret and returns it in a new buffer. |
| 132 | * |
| 133 | * <p>This method resets this <code>KeyAgreementSpi</code> object, |
| 134 | * so that it |
| 135 | * can be reused for further key agreements. Unless this key agreement is |
| 136 | * reinitialized with one of the <code>engineInit</code> methods, the same |
| 137 | * private information and algorithm parameters will be used for |
| 138 | * subsequent key agreements. |
| 139 | * |
| 140 | * @return the new buffer with the shared secret |
| 141 | * |
| 142 | * @exception IllegalStateException if this key agreement has not been |
| 143 | * completed yet |
| 144 | */ |
| 145 | protected abstract byte[] engineGenerateSecret() |
| 146 | throws IllegalStateException; |
| 147 | |
| 148 | /** |
| 149 | * Generates the shared secret, and places it into the buffer |
| 150 | * <code>sharedSecret</code>, beginning at <code>offset</code> inclusive. |
| 151 | * |
| 152 | * <p>If the <code>sharedSecret</code> buffer is too small to hold the |
| 153 | * result, a <code>ShortBufferException</code> is thrown. |
| 154 | * In this case, this call should be repeated with a larger output buffer. |
| 155 | * |
| 156 | * <p>This method resets this <code>KeyAgreementSpi</code> object, |
| 157 | * so that it |
| 158 | * can be reused for further key agreements. Unless this key agreement is |
| 159 | * reinitialized with one of the <code>engineInit</code> methods, the same |
| 160 | * private information and algorithm parameters will be used for |
| 161 | * subsequent key agreements. |
| 162 | * |
| 163 | * @param sharedSecret the buffer for the shared secret |
| 164 | * @param offset the offset in <code>sharedSecret</code> where the |
| 165 | * shared secret will be stored |
| 166 | * |
| 167 | * @return the number of bytes placed into <code>sharedSecret</code> |
| 168 | * |
| 169 | * @exception IllegalStateException if this key agreement has not been |
| 170 | * completed yet |
| 171 | * @exception ShortBufferException if the given output buffer is too small |
| 172 | * to hold the secret |
| 173 | */ |
| 174 | protected abstract int engineGenerateSecret(byte[] sharedSecret, |
| 175 | int offset) |
| 176 | throws IllegalStateException, ShortBufferException; |
| 177 | |
| 178 | /** |
| 179 | * Creates the shared secret and returns it as a secret key object |
| 180 | * of the requested algorithm type. |
| 181 | * |
| 182 | * <p>This method resets this <code>KeyAgreementSpi</code> object, |
| 183 | * so that it |
| 184 | * can be reused for further key agreements. Unless this key agreement is |
| 185 | * reinitialized with one of the <code>engineInit</code> methods, the same |
| 186 | * private information and algorithm parameters will be used for |
| 187 | * subsequent key agreements. |
| 188 | * |
| 189 | * @param algorithm the requested secret key algorithm |
| 190 | * |
| 191 | * @return the shared secret key |
| 192 | * |
| 193 | * @exception IllegalStateException if this key agreement has not been |
| 194 | * completed yet |
| 195 | * @exception NoSuchAlgorithmException if the requested secret key |
| 196 | * algorithm is not available |
| 197 | * @exception InvalidKeyException if the shared secret key material cannot |
| 198 | * be used to generate a secret key of the requested algorithm type (e.g., |
| 199 | * the key material is too short) |
| 200 | */ |
| 201 | protected abstract SecretKey engineGenerateSecret(String algorithm) |
| 202 | throws IllegalStateException, NoSuchAlgorithmException, |
| 203 | InvalidKeyException; |
| 204 | } |