org.bouncycastle.jcajce.io
Class CipherOutputStream

java.lang.Object
  java.io.OutputStream
      java.io.FilterOutputStream
          org.bouncycastle.jcajce.io.CipherOutputStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable

public class CipherOutputStream
extends java.io.FilterOutputStream

A CipherOutputStream is composed of an OutputStream and a cipher so that write() methods process the written data with the cipher, and the output of the cipher is in turn written to the underlying OutputStream. The cipher must be fully initialized before being used by a CipherInputStream.

For example, if the cipher is initialized for encryption, the CipherOutputStream will encrypt the data before writing the encrypted data to the underlying stream.

This is a reimplementation of CipherOutputStream that is safe for use with AEAD block ciphers, and does not silently catch BadPaddingException and IllegalBlockSizeException errors. Any errors that occur during finalisation are rethrown wrapped in an InvalidCipherTextIOException.

Field Summary

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

CipherOutputStream(java.io.OutputStream output, javax.crypto.Cipher cipher)
Constructs a CipherOutputStream from an OutputStream and a Cipher.

Method Summary

void	close() Closes this output stream and releases any system resources associated with this stream.
void	flush() Flushes this output stream by forcing any buffered output bytes that have already been processed by the encapsulated cipher object to be written out.
void	write(byte[] b, int off, int len) Writes len bytes from the specified byte array starting at offset off to this output stream.
void	write(int b) Writes the specified byte to this output stream.

Methods inherited from class java.io.FilterOutputStream

write

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CipherOutputStream

public CipherOutputStream(java.io.OutputStream output,
                          javax.crypto.Cipher cipher)

Constructs a CipherOutputStream from an OutputStream and a Cipher.

Method Detail

write

public void write(int b)
           throws java.io.IOException

Writes the specified byte to this output stream.

Overrides:

write in class java.io.FilterOutputStream

Parameters:

b - the byte.

Throws:

java.io.IOException - if an I/O error occurs.

write

public void write(byte[] b,
                  int off,
                  int len)
           throws java.io.IOException

Writes len bytes from the specified byte array starting at offset off to this output stream.

Overrides:

write in class java.io.FilterOutputStream

Parameters:

b - the data.

off - the start offset in the data.

len - the number of bytes to write.

Throws:

java.io.IOException - if an I/O error occurs.

flush

public void flush()
           throws java.io.IOException

Flushes this output stream by forcing any buffered output bytes that have already been processed by the encapsulated cipher object to be written out.

Any bytes buffered by the encapsulated cipher and waiting to be processed by it will not be written out. For example, if the encapsulated cipher is a block cipher, and the total number of bytes written using one of the write methods is less than the cipher's block size, no bytes will be written out.

Specified by:

flush in interface java.io.Flushable

Overrides:

flush in class java.io.FilterOutputStream

Throws:

java.io.IOException - if an I/O error occurs.

close

public void close()
           throws java.io.IOException

Closes this output stream and releases any system resources associated with this stream.

This method invokes the doFinal method of the encapsulated cipher object, which causes any bytes buffered by the encapsulated cipher to be processed. The result is written out by calling the flush method of this output stream.

This method resets the encapsulated cipher object to its initial state and calls the close method of the underlying output stream.

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.FilterOutputStream

Throws:

java.io.IOException - if an I/O error occurs.

InvalidCipherTextIOException - if the data written to this stream was invalid ciphertext (e.g. the cipher is an AEAD cipher and the ciphertext tag check fails).