- All Implemented Interfaces:
Closeable,Flushable,AutoCloseable
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 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.
- Since:
- 1.4
- See Also:
-
Field Summary
Fields declared in class java.io.FilterOutputStream
out -
Constructor Summary
ConstructorsModifierConstructorDescriptionprotectedConstructs a CipherOutputStream from an OutputStream without specifying a Cipher.CipherOutputStream(OutputStream os, Cipher c) Constructs a CipherOutputStream from an OutputStream and a Cipher. -
Method Summary
Modifier and TypeMethodDescriptionvoidclose()Closes this output stream and releases any system resources associated with this stream.voidflush()Flushes this output stream by forcing any buffered output bytes that have already been processed by the encapsulated cipher object to be written out.voidwrite(byte[] b) Writesb.lengthbytes from the specified byte array to this output stream.voidwrite(byte[] b, int off, int len) Writeslenbytes from the specified byte array starting at offsetoffto this output stream.voidwrite(int b) Writes the specified byte to this output stream.Methods declared in class java.io.OutputStream
nullOutputStream
-
Constructor Details
-
CipherOutputStream
Constructs a CipherOutputStream from an OutputStream and a Cipher.
Note: if the specified output stream or cipher is null, a NullPointerException may be thrown later when they are used.- Parameters:
os- the OutputStream objectc- an initialized Cipher object
-
CipherOutputStream
Constructs a CipherOutputStream from an OutputStream without specifying a Cipher. This has the effect of constructing a CipherOutputStream using a NullCipher.
Note: if the specified output stream is null, a NullPointerException may be thrown later when it is used.- Parameters:
os- the OutputStream object
-
-
Method Details
-
write
Writes the specified byte to this output stream.- Overrides:
writein classFilterOutputStream- Parameters:
b- thebyte.- Throws:
IOException- if an I/O error occurs.
-
write
Writesb.lengthbytes from the specified byte array to this output stream.The
writemethod ofCipherOutputStreamcalls thewritemethod of three arguments with the three argumentsb,0, andb.length.- Overrides:
writein classFilterOutputStream- Parameters:
b- the data.- Throws:
NullPointerException- ifbis null.IOException- if an I/O error occurs.- See Also:
-
write
Writeslenbytes from the specified byte array starting at offsetoffto this output stream.- Overrides:
writein classFilterOutputStream- Parameters:
b- the data.off- the start offset in the data.len- the number of bytes to write.- Throws:
IOException- if an I/O error occurs.- See Also:
-
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.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
writemethods is less than the cipher's block size, no bytes will be written out.- Specified by:
flushin interfaceFlushable- Overrides:
flushin classFilterOutputStream- Throws:
IOException- if an I/O error occurs.- See Also:
-
close
Closes this output stream and releases any system resources associated with this stream.This method invokes the
doFinalmethod of the encapsulated cipher object, which causes any bytes buffered by the encapsulated cipher to be processed. The result is written out by calling theflushmethod of this output stream.This method resets the encapsulated cipher object to its initial state and calls the
closemethod of the underlying output stream.- Specified by:
closein interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Overrides:
closein classFilterOutputStream- Throws:
IOException- if an I/O error occurs.- See Also:
-