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| 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.io.*; | ||
| 29 | |||
| 30 | /** | ||
| 31 | * A CipherOutputStream is composed of an OutputStream and a Cipher so | ||
| 32 | * that write() methods first process the data before writing them out | ||
| 33 | * to the underlying OutputStream. The cipher must be fully | ||
| 34 | * initialized before being used by a CipherOutputStream. | ||
| 35 | * | ||
| 36 | * <p> For example, if the cipher is initialized for encryption, the | ||
| 37 | * CipherOutputStream will attempt to encrypt data before writing out the | ||
| 38 | * encrypted data. | ||
| 39 | * | ||
| 40 | * <p> This class adheres strictly to the semantics, especially the | ||
| 41 | * failure semantics, of its ancestor classes | ||
| 42 | * java.io.OutputStream and java.io.FilterOutputStream. This class | ||
| 43 | * has exactly those methods specified in its ancestor classes, and | ||
| 44 | * overrides them all. Moreover, this class catches all exceptions | ||
| 45 | * that are not thrown by its ancestor classes. | ||
| 46 | * | ||
| 47 | * <p> It is crucial for a programmer using this class not to use | ||
| 48 | * methods that are not defined or overriden in this class (such as a | ||
| 49 | * new method or constructor that is later added to one of the super | ||
| 50 | * classes), because the design and implementation of those methods | ||
| 51 | * are unlikely to have considered security impact with regard to | ||
| 52 | * CipherOutputStream. | ||
| 53 | * | ||
| 54 | * @author Li Gong | ||
| 55 | * @see java.io.OutputStream | ||
| 56 | * @see java.io.FilterOutputStream | ||
| 57 | * @see javax.crypto.Cipher | ||
| 58 | * @see javax.crypto.CipherInputStream | ||
| 59 | * | ||
| 60 | * @since 1.4 | ||
| 61 | */ | ||
| 62 | |||
| 63 | public class CipherOutputStream extends FilterOutputStream { | ||
| 64 | |||
| 65 | // the cipher engine to use to process stream data | ||
| 66 | private Cipher cipher; | ||
| 67 | |||
| 68 | // the underlying output stream | ||
| 69 | private OutputStream output; | ||
| 70 | |||
| 71 | /* the buffer holding one byte of incoming data */ | ||
| 72 | private byte[] ibuffer = new byte[1]; | ||
| 73 | |||
| 74 | // the buffer holding data ready to be written out | ||
| 75 | private byte[] obuffer; | ||
| 76 | |||
| 77 | /** | ||
| 78 | * | ||
| 79 | * Constructs a CipherOutputStream from an OutputStream and a | ||
| 80 | * Cipher. | ||
| 81 | * <br>Note: if the specified output stream or cipher is | ||
| 82 | * null, a NullPointerException may be thrown later when | ||
| 83 | * they are used. | ||
| 84 | * | ||
| 85 | * @param os the OutputStream object | ||
| 86 | * @param c an initialized Cipher object | ||
| 87 | */ | ||
| 88 | public CipherOutputStream(OutputStream os, Cipher c) { | ||
| 89 | super(os); | ||
| 90 | output = os; | ||
| 91 | cipher = c; | ||
| 92 | }; | ||
| 93 | |||
| 94 | /** | ||
| 95 | * Constructs a CipherOutputStream from an OutputStream without | ||
| 96 | * specifying a Cipher. This has the effect of constructing a | ||
| 97 | * CipherOutputStream using a NullCipher. | ||
| 98 | * <br>Note: if the specified output stream is null, a | ||
| 99 | * NullPointerException may be thrown later when it is used. | ||
| 100 | * | ||
| 101 | * @param os the OutputStream object | ||
| 102 | */ | ||
| 103 | protected CipherOutputStream(OutputStream os) { | ||
| 104 | super(os); | ||
| 105 | output = os; | ||
| 106 | cipher = new NullCipher(); | ||
| 107 | } | ||
| 108 | |||
| 109 | /** | ||
| 110 | * Writes the specified byte to this output stream. | ||
| 111 | * | ||
| 112 | * @param b the <code>byte</code>. | ||
| 113 | * @exception IOException if an I/O error occurs. | ||
| 114 | * @since JCE1.2 | ||
| 115 | */ | ||
| 116 | public void write(int b) throws IOException { | ||
| 117 | ibuffer[0] = (byte) b; | ||
| 118 | obuffer = cipher.update(ibuffer, 0, 1); | ||
| 119 | if (obuffer != null) { | ||
| 120 | output.write(obuffer); | ||
| 121 | obuffer = null; | ||
| 122 | } | ||
| 123 | }; | ||
| 124 | |||
| 125 | /** | ||
| 126 | * Writes <code>b.length</code> bytes from the specified byte array | ||
| 127 | * to this output stream. | ||
| 128 | * <p> | ||
| 129 | * The <code>write</code> method of | ||
| 130 | * <code>CipherOutputStream</code> calls the <code>write</code> | ||
| 131 | * method of three arguments with the three arguments | ||
| 132 | * <code>b</code>, <code>0</code>, and <code>b.length</code>. | ||
| 133 | * | ||
| 134 | * @param b the data. | ||
| 135 | * @exception NullPointerException if <code>b</code> is null. | ||
| 136 | * @exception IOException if an I/O error occurs. | ||
| 137 | * @see javax.crypto.CipherOutputStream#write(byte[], int, int) | ||
| 138 | * @since JCE1.2 | ||
| 139 | */ | ||
| 140 | public void write(byte b[]) throws IOException { | ||
| 141 | write(b, 0, b.length); | ||
| 142 | } | ||
| 143 | |||
| 144 | /** | ||
| 145 | * Writes <code>len</code> bytes from the specified byte array | ||
| 146 | * starting at offset <code>off</code> to this output stream. | ||
| 147 | * | ||
| 148 | * @param b the data. | ||
| 149 | * @param off the start offset in the data. | ||
| 150 | * @param len the number of bytes to write. | ||
| 151 | * @exception IOException if an I/O error occurs. | ||
| 152 | * @since JCE1.2 | ||
| 153 | */ | ||
| 154 | public void write(byte b[], int off, int len) throws IOException { | ||
| 155 | obuffer = cipher.update(b, off, len); | ||
| 156 | if (obuffer != null) { | ||
| 157 | output.write(obuffer); | ||
| 158 | obuffer = null; | ||
| 159 | } | ||
| 160 | } | ||
| 161 | |||
| 162 | /** | ||
| 163 | * Flushes this output stream by forcing any buffered output bytes | ||
| 164 | * that have already been processed by the encapsulated cipher object | ||
| 165 | * to be written out. | ||
| 166 | * | ||
| 167 | * <p>Any bytes buffered by the encapsulated cipher | ||
| 168 | * and waiting to be processed by it will not be written out. For example, | ||
| 169 | * if the encapsulated cipher is a block cipher, and the total number of | ||
| 170 | * bytes written using one of the <code>write</code> methods is less than | ||
| 171 | * the cipher's block size, no bytes will be written out. | ||
| 172 | * | ||
| 173 | * @exception IOException if an I/O error occurs. | ||
| 174 | * @since JCE1.2 | ||
| 175 | */ | ||
| 176 | public void flush() throws IOException { | ||
| 177 | if (obuffer != null) { | ||
| 178 | output.write(obuffer); | ||
| 179 | obuffer = null; | ||
| 180 | } | ||
| 181 | output.flush(); | ||
| 182 | } | ||
| 183 | |||
| 184 | /** | ||
| 185 | * Closes this output stream and releases any system resources | ||
| 186 | * associated with this stream. | ||
| 187 | * <p> | ||
| 188 | * This method invokes the <code>doFinal</code> method of the encapsulated | ||
| 189 | * cipher object, which causes any bytes buffered by the encapsulated | ||
| 190 | * cipher to be processed. The result is written out by calling the | ||
| 191 | * <code>flush</code> method of this output stream. | ||
| 192 | * <p> | ||
| 193 | * This method resets the encapsulated cipher object to its initial state | ||
| 194 | * and calls the <code>close</code> method of the underlying output | ||
| 195 | * stream. | ||
| 196 | * | ||
| 197 | * @exception IOException if an I/O error occurs. | ||
| 198 | * @since JCE1.2 | ||
| 199 | */ | ||
| 200 | public void close() throws IOException { | ||
| 201 | try { | ||
| 202 | obuffer = cipher.doFinal(); | ||
| 203 | } catch (IllegalBlockSizeException e) { | ||
| 204 | obuffer = null; | ||
| 205 | } catch (BadPaddingException e) { | ||
| 206 | obuffer = null; | ||
| 207 | } | ||
| 208 | try { | ||
| 209 | flush(); | ||
| 210 | } catch (IOException ignored) {} | ||
| 211 | out.close(); | ||
| 212 | } | ||
| 213 | } | ||