org.apache.commons.crypto.stream

? PositionedCryptoInputStream

java.lang.Object

java.io.InputStream

org.apache.commons.crypto.stream.CryptoInputStream

org.apache.commons.crypto.stream.CtrCryptoInputStream

org.apache.commons.crypto.stream.PositionedCryptoInputStream

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Closeable, AutoCloseable, Channel, ReadableByteChannel

public class PositionedCryptoInputStream
extends CtrCryptoInputStream

PositionedCryptoInputStream provides the capability to decrypt the stream starting at random position as well as provides the foundation for positioned read for decrypting. This needs a stream cipher mode such as AES CTR mode.

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??????? org.apache.commons.crypto.stream.CryptoInputStream

STREAM_BUFFER_SIZE_KEY

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	PositionedCryptoInputStream(Properties props, Input in, byte[] key, byte[] iv, long streamOffset) Constructs a PositionedCryptoInputStream.
protected	PositionedCryptoInputStream(Properties props, Input input, CryptoCipher cipher, int bufferSize, byte[] key, byte[] iv, long streamOffset) Constructs a PositionedCryptoInputStream.

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void	close() Overrides the CryptoInputStream.close().
protected void	decrypt(long position, byte[] buffer, int offset, int length) Decrypts length bytes in buffer starting at offset.
int	read(long position, byte[] buffer, int offset, int length) Reads up to the specified number of bytes from a given position within a stream and return the number of bytes read.
void	readFully(long position, byte[] buffer) Reads the specified number of bytes from a given position within a stream.
void	readFully(long position, byte[] buffer, int offset, int length) Reads the specified number of bytes from a given position within a stream.

??????? org.apache.commons.crypto.stream.CtrCryptoInputStream

decrypt, decrypt, decryptBuffer, decryptInPlace, decryptMore, getCounter, getInitIV, getPadding, getStreamOffset, getStreamPosition, initCipher, postDecryption, read, resetCipher, resetStreamOffset, seek, setStreamOffset, skip

??????? org.apache.commons.crypto.stream.CryptoInputStream

available, checkStream, decryptFinal, freeBuffers, getBufferSize, getCipher, getInput, getKey, getParams, isOpen, mark, markSupported, read, read, reset

??????? java.io.InputStream

read

??????? java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

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PositionedCryptoInputStream

public PositionedCryptoInputStream(Properties props,
                                   Input in,
                                   byte[] key,
                                   byte[] iv,
                                   long streamOffset)
                            throws IOException

Constructs a PositionedCryptoInputStream.

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props - The Properties class represents a set of properties.

in - the input data.

key - crypto key for the cipher.

iv - Initialization vector for the cipher.

streamOffset - the start offset in the data.

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IOException - if an I/O error occurs.

PositionedCryptoInputStream

protected PositionedCryptoInputStream(Properties props,
                                      Input input,
                                      CryptoCipher cipher,
                                      int bufferSize,
                                      byte[] key,
                                      byte[] iv,
                                      long streamOffset)
                               throws IOException

Constructs a PositionedCryptoInputStream.

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props - the props of stream

input - the input data.

cipher - the CryptoCipher instance.

bufferSize - the bufferSize.

key - crypto key for the cipher.

iv - Initialization vector for the cipher.

streamOffset - the start offset in the data.

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IOException - if an I/O error occurs.

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read

public int read(long position,
                byte[] buffer,
                int offset,
                int length)
         throws IOException

Reads up to the specified number of bytes from a given position within a stream and return the number of bytes read. This does not change the current offset of the stream, and is thread-safe.

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buffer - the buffer into which the data is read.

length - the maximum number of bytes to read.

offset - the start offset in the data.

position - the offset from the start of the stream.

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int the total number of decrypted data bytes read into the buffer.

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IOException - if an I/O error occurs.

readFully

public void readFully(long position,
                      byte[] buffer,
                      int offset,
                      int length)
               throws IOException

Reads the specified number of bytes from a given position within a stream. This does not change the current offset of the stream and is thread-safe.

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buffer - the buffer into which the data is read.

length - the maximum number of bytes to read.

offset - the start offset in the data.

position - the offset from the start of the stream.

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IOException - if an I/O error occurs.

readFully

public void readFully(long position,
                      byte[] buffer)
               throws IOException

Reads the specified number of bytes from a given position within a stream. This does not change the current offset of the stream and is thread-safe.

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position - the offset from the start of the stream.

buffer - the buffer into which the data is read.

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IOException - if an I/O error occurs.

decrypt

protected void decrypt(long position,
                       byte[] buffer,
                       int offset,
                       int length)
                throws IOException

Decrypts length bytes in buffer starting at offset. Output is also put into buffer starting at offset. It is thread-safe.

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buffer - the buffer into which the data is read.

offset - the start offset in the data.

position - the offset from the start of the stream.

length - the maximum number of bytes to read.

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IOException - if an I/O error occurs.

close

public void close()
           throws IOException

Overrides the CryptoInputStream.close(). Closes this input stream and releases any system resources associated with the stream.

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close ???? Closeable

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close ???? AutoCloseable

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close ???? Channel

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close ??? CryptoInputStream

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IOException - if an I/O error occurs.