public class CipherOutputStream extends FilterOutputStream
For example, if the cipher is initialized for encryption, the CipherOutputStream will attempt to encrypt data before writing out the encrypted data.
This class adheres strictly to the semantics, especially the failure semantics, of its ancestor classes java.io.OutputStream and java.io.FilterOutputStream. This class has exactly those methods specified in its ancestor classes, and overrides them all. Moreover, this class catches all exceptions that are not thrown by its ancestor classes. In particular, this class catches BadPaddingException and other exceptions thrown by failed integrity checks during decryption. These exceptions are not re-thrown, so the client will not be informed that integrity checks failed. Because of this behavior, this class may not be suitable for use with decryption in an authenticated mode of operation (e.g. GCM) if the application requires explicit notification when authentication fails. Such an application can use the Cipher API directly as an alternative to using this class.
It is crucial for a programmer using this class not to use methods that are not defined or overriden in this class (such as a new method or constructor that is later added to one of the super classes), because the design and implementation of those methods are unlikely to have considered security impact with regard to CipherOutputStream.
|Modifier||Constructor and Description|
Constructs a CipherOutputStream from an OutputStream without specifying a Cipher.
Constructs a CipherOutputStream from an OutputStream and a Cipher.
|Modifier and Type||Method and Description|
Closes this output stream and releases any system resources associated with this stream.
Flushes this output stream by forcing any buffered output bytes that have already been processed by the encapsulated cipher object to be written out.
Writes the specified byte to this output stream.
public CipherOutputStream(OutputStream os, Cipher c)
os- the OutputStream object
c- an initialized Cipher object
protected CipherOutputStream(OutputStream os)
os- the OutputStream object
public void write(int b) throws IOException
public void write(byte b) throws IOException
b.lengthbytes from the specified byte array to this output stream.
write method of
CipherOutputStream calls the
method of three arguments with the three arguments
public void write(byte b, int off, int len) throws IOException
lenbytes from the specified byte array starting at offset
offto this output stream.
public void flush() throws IOException
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.
public void close() throws IOException
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
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For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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