- All Implemented Interfaces:
- Closeable,- AutoCloseable
CipherInputStream is composed of an InputStream
 and a Cipher object so that read() methods return data that are
 read in from the underlying InputStream but have been
 additionally processed by the Cipher object.  The Cipher
 object must be fully initialized before being used by a
 CipherInputStream.
  For example, if the Cipher object is initialized for decryption,
 the CipherInputStream will attempt to read in data and decrypt
 them, before returning the decrypted data.
 
 This class adheres strictly to the semantics, especially the
 failure semantics, of its ancestor classes
 java.io.FilterInputStream and java.io.InputStream.
 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, the
 skip method skips, and the available
 method counts only data that have been processed by the encapsulated
 Cipher object.
 This class may catch BadPaddingException and other exceptions
 thrown by failed integrity checks during decryption. These exceptions are not
 re-thrown, so the client may 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).
 Applications that require authenticated encryption 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
 CipherInputStream.
- Since:
- 1.4
- See Also:
- 
Field SummaryFields declared in class java.io.FilterInputStreamin
- 
Constructor SummaryConstructorsModifierConstructorDescriptionprotectedConstructs aCipherInputStreamfrom anInputStreamwithout specifying aCipherobject.CipherInputStream(InputStream is, Cipher c) Constructs aCipherInputStreamfrom anInputStreamand aCipherobject.
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Method SummaryModifier and TypeMethodDescriptionintReturns the number of bytes that can be read from this input stream without blocking.voidclose()Closes this input stream and releases any system resources associated with the stream.booleanTests if this input stream supports themarkandresetmethods, which it does not.intread()Reads the next byte of data from this input stream.intread(byte[] b) Reads up tob.lengthbytes of data from this input stream into an array of bytes.intread(byte[] b, int off, int len) Reads up tolenbytes of data from this input stream into an array of bytes.longskip(long n) Skipsnbytes of input from the bytes that can be read from this input stream without blocking.Methods declared in class java.io.FilterInputStreammark, resetMethods declared in class java.io.InputStreamnullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo
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Constructor Details- 
CipherInputStreamConstructs aCipherInputStreamfrom anInputStreamand aCipherobject.
 Note: if the specified input stream or cipher isnull, aNullPointerExceptionmay be thrown later when they are used.- Parameters:
- is- the to-be-processed input stream
- c- an initialized- Cipherobject
 
- 
CipherInputStreamConstructs aCipherInputStreamfrom anInputStreamwithout specifying aCipherobject. This has the effect of constructing aCipherInputStreamusing aNullCipher.
 Note: if the specified input stream isnull, aNullPointerExceptionmay be thrown later when it is used.- Parameters:
- is- the to-be-processed input stream
 
 
- 
- 
Method Details- 
readReads the next byte of data from this input stream. The value byte is returned as anintin the range0to255. If no byte is available because the end of the stream has been reached, the value-1is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.- Overrides:
- readin class- FilterInputStream
- Returns:
- the next byte of data, or -1if the end of the stream is reached.
- Throws:
- IOException- if an I/O error occurs.
- See Also:
 
- 
readReads up tob.lengthbytes of data from this input stream into an array of bytes.The readmethod ofInputStreamcalls thereadmethod of three arguments with the argumentsb,0, andb.length.- Overrides:
- readin class- FilterInputStream
- Parameters:
- b- the buffer into which the data is read.
- Returns:
- the total number of bytes read into the buffer, or
             -1is there is no more data because the end of the stream has been reached.
- Throws:
- IOException- if an I/O error occurs.
- See Also:
 
- 
readReads up tolenbytes of data from this input stream into an array of bytes. This method blocks until some input is available. If the first argument isnull, up tolenbytes are read and discarded.- Overrides:
- readin class- FilterInputStream
- Parameters:
- b- the buffer into which the data is read.
- off- the start offset in the destination array- buf
- len- the maximum number of bytes read.
- Returns:
- the total number of bytes read into the buffer, or
             -1if there is no more data because the end of the stream has been reached.
- Throws:
- IOException- if an I/O error occurs.
- See Also:
 
- 
skipSkipsnbytes of input from the bytes that can be read from this input stream without blocking.Fewer bytes than requested might be skipped. The actual number of bytes skipped is equal to nor the result of a call toavailable, whichever is smaller. Ifnis less than zero, no bytes are skipped.The actual number of bytes skipped is returned. - Overrides:
- skipin class- FilterInputStream
- Parameters:
- n- the number of bytes to be skipped.
- Returns:
- the actual number of bytes skipped.
- Throws:
- IOException- if an I/O error occurs.
- See Also:
 
- 
availableReturns the number of bytes that can be read from this input stream without blocking. Theavailablemethod ofInputStreamreturns0. This method should be overridden by subclasses.- Overrides:
- availablein class- FilterInputStream
- Returns:
- the number of bytes that can be read from this input stream without blocking.
- Throws:
- IOException- if an I/O error occurs.
 
- 
closeCloses this input stream and releases any system resources associated with the stream.The closemethod ofCipherInputStreamcalls theclosemethod of its underlying input stream.- Specified by:
- closein interface- AutoCloseable
- Specified by:
- closein interface- Closeable
- Overrides:
- closein class- FilterInputStream
- Throws:
- IOException- if an I/O error occurs.
- See Also:
 
- 
markSupportedpublic boolean markSupported()Tests if this input stream supports themarkandresetmethods, which it does not.- Overrides:
- markSupportedin class- FilterInputStream
- Returns:
- false, since this class does not support the- markand- resetmethods.
- See Also:
 
 
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