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Class javax.crypto.CipherOutputStream
java.lang.Object
|
+----java.io.OutputStream
|
+----java.io.FilterOutputStream
|
+----javax.crypto.CipherOutputStream
- public class CipherOutputStream
- extends FilterOutputStream
A CipherOutputStream is composed of an OutputStream and a Cipher so that
write() methods first process the data before writing them out to the
underlying OutputStream. The cipher must be fully initialised before being
used by a CipherOutputStream.
For example, if the cipher is initialised 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.
It is crucial for a programmer using this class not to use methods that are
not defined or overridden 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.
- See Also:
- OutputStream, FilterOutputStream, Cipher, CipherInputStream
-
ident
-
-
CipherOutputStream(OutputStream)
- Constructs a CipherOutputStream from an OutputStream without
specifying a Cipher.
-
CipherOutputStream(OutputStream, Cipher)
- Constructs a CipherOutputStream from an OutputStream and a Cipher.
-
close()
- Closes this output stream and releases any system resources
associated with this stream.
-
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.
-
write(byte[])
- Writes b.length bytes from the specified byte array to this output
stream.
-
write(byte[], int, int)
- Writes len bytes from the specified byte array starting at offset
off to this output stream.
-
write(int)
- Writes the specified byte to this output stream.
ident
public static final String ident
CipherOutputStream
public CipherOutputStream(OutputStream out,
Cipher cipher)
- Constructs a CipherOutputStream from an OutputStream and a Cipher.
- Parameters:
- out - The output stream.
- cipher - The encrypting object.
CipherOutputStream
public CipherOutputStream(OutputStream out)
- Constructs a CipherOutputStream from an OutputStream without
specifying a Cipher. This has the effect of constructing a
CipherOutputStream using a NullCipher.
- Parameters:
- out - The output stream.
write
public void write(int b) throws IOException
- Writes the specified byte to this output stream.
- Parameters:
- b - The byte to write.
- Throws: IOException
- If an I/O error occurs.
- Overrides:
- write in class FilterOutputStream
write
public void write(byte b[]) throws IOException
- Writes b.length bytes from the specified byte array to this output
stream.
The write method of CipherOutputStream calls the write method of
three arguments with the three arguments b, 0, and b.length.
- Parameters:
- b - the data.
- Throws: IOException
- if an I/O error occurs.
- Overrides:
- write in class FilterOutputStream
- See Also:
- write
write
public void write(byte b[],
int off,
int len) throws IOException
- Writes len bytes from the specified byte array starting at offset
off to this output stream.
- Parameters:
- b - The bytes to be written.
- off - The index of the first byte to write.
- len - The number of bytes to write.
- Throws: IOException
- If an I/O error occurs.
- Overrides:
- write in class FilterOutputStream
flush
public void flush() throws 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.
- Throws: IOException
- if an I/O error occurs
- Overrides:
- flush in class FilterOutputStream
close
public void close() throws 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.
- Throws: IOException
- if an I/O error occurs
- Overrides:
- close in class FilterOutputStream
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