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The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8. Note: this package includes the NTRU encryption algorithms.

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package org.bouncycastle.jcajce.io;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.GeneralSecurityException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;

import org.bouncycastle.crypto.io.InvalidCipherTextIOException;

/**
 * A CipherInputStream is composed of an InputStream and a cipher so that read() methods return data
 * that are read in from the underlying InputStream but have been additionally processed by the
 * Cipher. The cipher must be fully initialized before being used by a CipherInputStream.
 * 

* For example, if the Cipher is initialized for decryption, the CipherInputStream will attempt to * read in data and decrypt them, before returning the decrypted data. *

* This is a reimplementation of {@link javax.crypto.CipherInputStream} that is safe for use with * AEAD block ciphers, and does not silently catch {@link BadPaddingException} and * {@link IllegalBlockSizeException} errors. Any errors that occur during {@link Cipher#doFinal() * finalisation} are rethrown wrapped in an {@link InvalidCipherTextIOException}. *

*/ public class CipherInputStream extends FilterInputStream { private final Cipher cipher; private final byte[] inputBuffer = new byte[512]; private boolean finalized = false; private byte[] buf; private int maxBuf; private int bufOff; /** * Constructs a CipherInputStream from an InputStream and an initialised Cipher. */ public CipherInputStream(InputStream input, Cipher cipher) { super(input); this.cipher = cipher; } /** * Read data from underlying stream and process with cipher until end of stream or some data is * available after cipher processing. * * @return -1 to indicate end of stream, or the number of bytes (> 0) available. */ private int nextChunk() throws IOException { if (finalized) { return -1; } bufOff = 0; maxBuf = 0; // Keep reading until EOF or cipher processing produces data while (maxBuf == 0) { int read = in.read(inputBuffer); if (read == -1) { buf = finaliseCipher(); if ((buf == null) || (buf.length == 0)) { return -1; } maxBuf = buf.length; return maxBuf; } buf = cipher.update(inputBuffer, 0, read); if (buf != null) { maxBuf = buf.length; } } return maxBuf; } private byte[] finaliseCipher() throws InvalidCipherTextIOException { try { finalized = true; return cipher.doFinal(); } catch (GeneralSecurityException e) { throw new InvalidCipherTextIOException("Error finalising cipher", e); } } /** * Reads data from the underlying stream and processes it with the cipher until the cipher * outputs data, and returns the next available byte. *

* If the underlying stream is exhausted by this call, the cipher will be finalised. *

* @throws IOException if there was an error closing the input stream. * @throws InvalidCipherTextIOException if the data read from the stream was invalid ciphertext * (e.g. the cipher is an AEAD cipher and the ciphertext tag check fails). */ public int read() throws IOException { if (bufOff >= maxBuf) { if (nextChunk() < 0) { return -1; } } return buf[bufOff++] & 0xff; } /** * Reads data from the underlying stream and processes it with the cipher until the cipher * outputs data, and then returns up to len bytes in the provided array. *

* If the underlying stream is exhausted by this call, the cipher will be finalised. *

* @param b the buffer into which the data is read. * @param off the start offset in the destination array b * @param len the maximum number of bytes read. * @return the total number of bytes read into the buffer, or -1 if there is no * more data because the end of the stream has been reached. * @throws IOException if there was an error closing the input stream. * @throws InvalidCipherTextIOException if the data read from the stream was invalid ciphertext * (e.g. the cipher is an AEAD cipher and the ciphertext tag check fails). */ public int read(byte[] b, int off, int len) throws IOException { if (bufOff >= maxBuf) { if (nextChunk() < 0) { return -1; } } int toSupply = Math.min(len, available()); System.arraycopy(buf, bufOff, b, off, toSupply); bufOff += toSupply; return toSupply; } public long skip(long n) throws IOException { if (n <= 0) { return 0; } int skip = (int)Math.min(n, available()); bufOff += skip; return skip; } public int available() throws IOException { return maxBuf - bufOff; } /** * Closes the underlying input stream, and then finalises the processing of the data by the * cipher. * * @throws IOException if there was an error closing the input stream. * @throws InvalidCipherTextIOException if the data read from the stream was invalid ciphertext * (e.g. the cipher is an AEAD cipher and the ciphertext tag check fails). */ public void close() throws IOException { try { in.close(); } finally { if (!finalized) { // Reset the cipher, discarding any data buffered in it // Errors in cipher finalisation trump I/O error closing input finaliseCipher(); } } maxBuf = bufOff = 0; } public void mark(int readlimit) { } public void reset() throws IOException { } public boolean markSupported() { return false; } }




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