222 lines
7.6 KiB
Java
222 lines
7.6 KiB
Java
/*
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* Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package javax.crypto;
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import java.io.*;
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/**
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* A CipherOutputStream is composed of an OutputStream and a Cipher so
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* that write() methods first process the data before writing them out
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* to the underlying OutputStream. The cipher must be fully
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* initialized before being used by a CipherOutputStream.
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*
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* <p> For example, if the cipher is initialized for encryption, the
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* CipherOutputStream will attempt to encrypt data before writing out the
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* encrypted data.
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*
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* <p> This class adheres strictly to the semantics, especially the
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* failure semantics, of its ancestor classes
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* java.io.OutputStream and java.io.FilterOutputStream. This class
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* has exactly those methods specified in its ancestor classes, and
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* overrides them all. Moreover, this class catches all exceptions
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* that are not thrown by its ancestor classes.
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*
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* <p> It is crucial for a programmer using this class not to use
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* methods that are not defined or overriden in this class (such as a
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* new method or constructor that is later added to one of the super
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* classes), because the design and implementation of those methods
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* are unlikely to have considered security impact with regard to
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* CipherOutputStream.
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*
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* @author Li Gong
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* @see java.io.OutputStream
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* @see java.io.FilterOutputStream
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* @see javax.crypto.Cipher
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* @see javax.crypto.CipherInputStream
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*
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* @since 1.4
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*/
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public class CipherOutputStream extends FilterOutputStream {
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// the cipher engine to use to process stream data
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private Cipher cipher;
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// the underlying output stream
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private OutputStream output;
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/* the buffer holding one byte of incoming data */
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private byte[] ibuffer = new byte[1];
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// the buffer holding data ready to be written out
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private byte[] obuffer;
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// stream status
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private boolean closed = false;
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/**
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*
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* Constructs a CipherOutputStream from an OutputStream and a
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* Cipher.
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* <br>Note: if the specified output stream or cipher is
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* null, a NullPointerException may be thrown later when
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* they are used.
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*
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* @param os the OutputStream object
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* @param c an initialized Cipher object
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*/
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public CipherOutputStream(OutputStream os, Cipher c) {
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super(os);
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output = os;
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cipher = c;
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};
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/**
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* Constructs a CipherOutputStream from an OutputStream without
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* specifying a Cipher. This has the effect of constructing a
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* CipherOutputStream using a NullCipher.
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* <br>Note: if the specified output stream is null, a
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* NullPointerException may be thrown later when it is used.
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*
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* @param os the OutputStream object
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*/
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protected CipherOutputStream(OutputStream os) {
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super(os);
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output = os;
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cipher = new NullCipher();
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}
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/**
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* Writes the specified byte to this output stream.
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*
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* @param b the <code>byte</code>.
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* @exception IOException if an I/O error occurs.
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* @since JCE1.2
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*/
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public void write(int b) throws IOException {
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ibuffer[0] = (byte) b;
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obuffer = cipher.update(ibuffer, 0, 1);
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if (obuffer != null) {
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output.write(obuffer);
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obuffer = null;
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}
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};
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/**
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* Writes <code>b.length</code> bytes from the specified byte array
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* to this output stream.
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* <p>
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* The <code>write</code> method of
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* <code>CipherOutputStream</code> calls the <code>write</code>
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* method of three arguments with the three arguments
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* <code>b</code>, <code>0</code>, and <code>b.length</code>.
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*
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* @param b the data.
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* @exception NullPointerException if <code>b</code> is null.
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* @exception IOException if an I/O error occurs.
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* @see javax.crypto.CipherOutputStream#write(byte[], int, int)
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* @since JCE1.2
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*/
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public void write(byte b[]) throws IOException {
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write(b, 0, b.length);
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}
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/**
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* Writes <code>len</code> bytes from the specified byte array
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* starting at offset <code>off</code> to this output stream.
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*
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* @param b the data.
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* @param off the start offset in the data.
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* @param len the number of bytes to write.
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* @exception IOException if an I/O error occurs.
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* @since JCE1.2
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*/
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public void write(byte b[], int off, int len) throws IOException {
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obuffer = cipher.update(b, off, len);
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if (obuffer != null) {
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output.write(obuffer);
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obuffer = null;
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}
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}
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/**
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* Flushes this output stream by forcing any buffered output bytes
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* that have already been processed by the encapsulated cipher object
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* to be written out.
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*
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* <p>Any bytes buffered by the encapsulated cipher
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* and waiting to be processed by it will not be written out. For example,
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* if the encapsulated cipher is a block cipher, and the total number of
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* bytes written using one of the <code>write</code> methods is less than
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* the cipher's block size, no bytes will be written out.
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*
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* @exception IOException if an I/O error occurs.
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* @since JCE1.2
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*/
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public void flush() throws IOException {
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if (obuffer != null) {
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output.write(obuffer);
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obuffer = null;
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}
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output.flush();
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}
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/**
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* Closes this output stream and releases any system resources
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* associated with this stream.
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* <p>
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* This method invokes the <code>doFinal</code> method of the encapsulated
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* cipher object, which causes any bytes buffered by the encapsulated
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* cipher to be processed. The result is written out by calling the
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* <code>flush</code> method of this output stream.
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* <p>
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* This method resets the encapsulated cipher object to its initial state
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* and calls the <code>close</code> method of the underlying output
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* stream.
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*
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* @exception IOException if an I/O error occurs.
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* @since JCE1.2
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*/
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public void close() throws IOException {
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if (closed) {
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return;
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}
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closed = true;
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try {
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obuffer = cipher.doFinal();
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} catch (IllegalBlockSizeException | BadPaddingException e) {
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obuffer = null;
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// Android-added: Throw an exception when the underlying cipher does. http://b/36636576
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throw new IOException(e);
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}
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try {
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flush();
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} catch (IOException ignored) {}
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out.close();
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}
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}
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