com.itextpdf.text.pdf.OutputStreamEncryption Maven / Gradle / Ivy
/*
*
* This file is part of the iText (R) project.
Copyright (c) 1998-2017 iText Group NV
* Authors: Bruno Lowagie, Paulo Soares, et al.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License version 3
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* following permission added to Section 15 as permitted in Section 7(a):
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* Section 5 of the GNU Affero General Public License.
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*
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package com.itextpdf.text.pdf;
import com.itextpdf.text.ExceptionConverter;
import com.itextpdf.text.pdf.crypto.AESCipher;
import com.itextpdf.text.pdf.crypto.IVGenerator;
import com.itextpdf.text.pdf.crypto.ARCFOUREncryption;
import java.io.IOException;
import java.io.OutputStream;
public class OutputStreamEncryption extends OutputStream {
protected OutputStream out;
protected ARCFOUREncryption arcfour;
protected AESCipher cipher;
private byte[] sb = new byte[1];
private static final int AES_128 = 4;
private static final int AES_256 = 5;
private boolean aes;
private boolean finished;
/** Creates a new instance of OutputStreamCounter */
public OutputStreamEncryption(OutputStream out, byte key[], int off, int len, int revision) {
try {
this.out = out;
aes = (revision == AES_128 || revision == AES_256);
if (aes) {
byte[] iv = IVGenerator.getIV();
byte[] nkey = new byte[len];
System.arraycopy(key, off, nkey, 0, len);
cipher = new AESCipher(true, nkey, iv);
write(iv);
}
else {
arcfour = new ARCFOUREncryption();
arcfour.prepareARCFOURKey(key, off, len);
}
} catch (Exception ex) {
throw new ExceptionConverter(ex);
}
}
public OutputStreamEncryption(OutputStream out, byte key[], int revision) {
this(out, key, 0, key.length, revision);
}
/** Closes this output stream and releases any system resources
* associated with this stream. The general contract of close
* is that it closes the output stream. A closed stream cannot perform
* output operations and cannot be reopened.
*
* The close method of OutputStream does nothing.
*
* @exception IOException if an I/O error occurs.
*
*/
public void close() throws IOException {
finish();
out.close();
}
/** Flushes this output stream and forces any buffered output bytes
* to be written out. The general contract of flush is
* that calling it is an indication that, if any bytes previously
* written have been buffered by the implementation of the output
* stream, such bytes should immediately be written to their
* intended destination.
*
* The flush method of OutputStream does nothing.
*
* @exception IOException if an I/O error occurs.
*
*/
public void flush() throws IOException {
out.flush();
}
/** Writes b.length bytes from the specified byte array
* to this output stream. The general contract for write(b)
* is that it should have exactly the same effect as the call
* write(b, 0, b.length).
*
* @param b the data.
* @exception IOException if an I/O error occurs.
* @see java.io.OutputStream#write(byte[], int, int)
*
*/
public void write(byte[] b) throws IOException {
write(b, 0, b.length);
}
/** Writes the specified byte to this output stream. The general
* contract for write is that one byte is written
* to the output stream. The byte to be written is the eight
* low-order bits of the argument b. The 24
* high-order bits of b are ignored.
*
* Subclasses of OutputStream must provide an
* implementation for this method.
*
* @param b the byte.
* @exception IOException if an I/O error occurs. In particular,
* an IOException may be thrown if the
* output stream has been closed.
*
*/
public void write(int b) throws IOException {
sb[0] = (byte)b;
write(sb, 0, 1);
}
/** Writes len bytes from the specified byte array
* starting at offset off to this output stream.
* The general contract for write(b, off, len) is that
* some of the bytes in the array b are written to the
* output stream in order; element b[off] is the first
* byte written and b[off+len-1] is the last byte written
* by this operation.
*
* The write method of OutputStream calls
* the write method of one argument on each of the bytes to be
* written out. Subclasses are encouraged to override this method and
* provide a more efficient implementation.
*
* If b is null, a
* NullPointerException is thrown.
*
* If off is negative, or len is negative, or
* off+len is greater than the length of the array
* b, then an IndexOutOfBoundsException is thrown.
*
* @param b the data.
* @param off the start offset in the data.
* @param len the number of bytes to write.
* @exception IOException if an I/O error occurs. In particular,
* an IOException is thrown if the output
* stream is closed.
*
*/
public void write(byte[] b, int off, int len) throws IOException {
if (aes) {
byte[] b2 = cipher.update(b, off, len);
if (b2 == null || b2.length == 0)
return;
out.write(b2, 0, b2.length);
}
else {
byte[] b2 = new byte[Math.min(len, 4192)];
while (len > 0) {
int sz = Math.min(len, b2.length);
arcfour.encryptARCFOUR(b, off, sz, b2, 0);
out.write(b2, 0, sz);
len -= sz;
off += sz;
}
}
}
public void finish() throws IOException {
if (!finished) {
finished = true;
if (aes) {
byte[] b;
try {
b = cipher.doFinal();
} catch (Exception ex) {
throw new ExceptionConverter(ex);
}
out.write(b, 0, b.length);
}
}
}
}