h48108 s 00006/00076/00304 d D 1.4 97/12/09 15:24:42 luehe 5 4 c rm ,* e s 00000/00019/00380 d D 1.3 97/10/22 15:25:05 luehe 4 3 c removed examples e s 00020/00021/00379 d D 1.2 97/10/18 13:59:53 luehe 3 1 c removed examples e s 00000/00000/00000 d R 1.2 97/10/09 09:58:13 Codemgr 2 1 c SunPro Code Manager data about conflicts, renames, etc... c Name history : 1 0 security/JCE1.2/earlyaccess/javax.crypto.CipherInputStream.html e s 00400/00000/00000 d D 1.1 97/10/09 09:58:12 luehe 1 0 c date and time created 97/10/09 09:58:12 by luehe e u U f e 0 t T I 1
D 3 E 3 I 3 D 5 E 5 I 5 E 5 E 3D 3 All Packages Class Hierarchy This Package Previous Next IndexE 3 I 3 All Packages Class Hierarchy This Package Previous Next Index E 3
java.lang.Object | +----java.io.InputStream | +----java.io.FilterInputStream | +----javax.crypto.CipherInputStream
For example, if the Cipher is initialized for decryption, the D 3 SecureInputStream will attempt to read in data and decrypt them, E 3 I 3 CipherInputStream will attempt to read in data and decrypt them, E 3 before returning the decrypted data.
This class adheres strictly to the semantics, especially the
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failure semantics, given for its ancestor classes
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failure semantics, of its ancestor classes
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java.io.FilterInputStream and java.io.InputStream. This class has
exactly those methods specified in its ancestor classes, and
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override them all. Moreover, this class catches all exceptions
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overrides them all. Moreover, this class catches all exceptions
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that are not thrown by its ancestor classes. In particular, the
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skip(long)
method skips only data that have been
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skip(long)
method skips only data that have been
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processed by the Cipher.
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It is crucial for a programmer using this class to not to use E 3 I 3
It is crucial for a programmer using this class not to use E 3 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 CipherInputStream. D 3
As an example of its usage, suppose cipher1 and cipher2 have been initialized for encryption and decryption (with corresponding crypto keys) respectively, the code below demonstrates how to easily connect several instances of SecureInputStream and InputStream. E 3 I 3 D 4
As an example of its usage, suppose cipher1
and
cipher2
have been initialized for encryption and decryption
(with corresponding keys), respectively. The code below demonstrates how to
easily connect several instances of CipherInputStream and InputStream:
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The above program copies the content from file /tmp/a.txt to
/tmp/b.txt, except that in the process the content has been first
encrypted and then decrypted back.
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The above program copies the content from file /tmp/a.txt to /tmp/b.txt,
except that the content is first encrypted and then decrypted
back when it is read from /tmp/a.txt.
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FileInputStream fis = new FileInputStream("/tmp/a.txt");
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SecureInputStream sis1 = new SecureInputStream(fis, cipher1);
SecureInputStream sis2 = new SecureInputStream(sis1, cipher2);
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CipherInputStream cis1 = new CipherInputStream(fis, cipher1);
CipherInputStream cis2 = new CipherInputStream(cis1, cipher2);
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FileOutputStream fos = new FileOutputStream("/tmp/b.txt");
byte[] b = new byte[8];
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int i = sis2.read(b);
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int i = cis2.read(b);
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while (i != -1) {
fos.write(b, 0, i);
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i = sis2.read(b);
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i = cis2.read(b);
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}
mark
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and reset
methods.
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and reset
methods, which it does not.
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b.length
bytes of data from this input
stream into an array of bytes.
len
bytes of data from this input stream
into an array of bytes.
mark
method was last called on this input stream.
n
bytes of data from this
input stream.
public CipherInputStream(InputStream is, Cipher c)
protected CipherInputStream(InputStream is)
public int read() throws IOException
int
in the range
0
to 255
. If no byte is available
because the end of the stream has been reached, the value
-1
is returned. This method blocks until input data
is available, the end of the stream is detected, or an exception
is thrown.
-1
if the end of the
stream is reached.
public int read(byte b[]) throws IOException
b.length
bytes of data from this input
stream into an array of bytes.
The read
method of InputStream
calls
the read
method of three arguments with the arguments
b
, 0
, and b.length
.
-1
is there is no more data because the end of
the stream has been reached.
public int read(byte b[], int off, int len) throws IOException
len
bytes of data from this input stream
into an array of bytes. This method blocks until some input is
available. If the first argument is null,
up to
len
bytes are read and discarded.
-1
if there is no more data because the end of
the stream has been reached.
public long skip(long n) throws IOException
n
bytes of data from this
input stream. The skip
method may, for a variety of
reasons, end up skipping over some smaller number of bytes,
possibly 0
. The actual number of bytes skipped is
returned.
public int available() throws IOException
InputStream
returns 0
. This method
should be overridden by subclasses.
public void close() throws IOException
The close
method of CipherInputStream
calls the close
method of its underlying input
stream.
public synchronized void mark(int readlimit)
reset
method repositions this stream at
the last marked position so that subsequent reads re-read the same
bytes.
The readlimit
arguments tells this input stream to
allow that many bytes to be read before the mark position gets
invalidated.
The mark
method of FilterInputStream
calls the mark
method of its underlying input stream
with the readlimit
argument.
public synchronized void reset() throws IOException
mark
method was last called on this input stream.
The reset
method of FilterInputStream
calls the reset
method of its underlying input stream.
Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parser, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails, which, if it happens within readlimit bytes, allows the outer code to reset the stream and try another parser.
public boolean markSupported()
mark
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and reset
methods. The markSupported
method of CipherInputStream
calls the
markSupported
method of its underlying input stream
and returns whatever value that method returns.
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and reset
methods, which it does not.
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true
if this true type supports the mark and reset
method; false
otherwise.
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false
, since this class does not support the
mark
and reset
methods.
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