Class CipherInputStream

java.lang.Object

java.io.InputStream

tech.oxfordsemantic.jrdfox.io.CipherInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class CipherInputStream
extends InputStream

A class which wraps an input stream and decrypts the data read from it using AES-256-CBC. It is assumed that the input stream contains data in the following format: Initialization vector (16 bytes) followed by a sequence of encrypted blocks. Each encrypted block is preceded by 8 bytes which are interpreted as an unsigned integer in little-endian encoding. The integer denotes the size (in bytes) of the data within the block (before padding is applied). The data within the block is padded to the next multiple of the cipher block size and encrypted using AES-256-CBC.

Constructor Summary

Constructors

Constructor	Description
CipherInputStream(InputStream inputStream)	Creates a new CipherInputStream object to decrypt the content of the provided input stream.

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the input stream.
boolean	initialize(Key key)	Initializes the cipher with the provided key and reads the initialization vector from the input stream.
int	read()	Reads the next byte of data from the input stream.
int	read(byte[] bytes, int off, int len)	Reads up to len bytes of data from the input stream into an array of bytes.

Methods inherited from class InputStream

available, mark, markSupported, nullInputStream, read, readAllBytes, readNBytes, readNBytes, reset, skip, skipNBytes, transferTo

Methods inherited from class Object

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

Constructor Details

CipherInputStream

public CipherInputStream(InputStream inputStream)
                  throws IOException

Creates a new CipherInputStream object to decrypt the content of the provided input stream.

Parameters:

inputStream - the input stream from which the data will be read

Throws:

IOException - if an I/O error occurs

Method Details

initialize

public boolean initialize(Key key)
                   throws InvalidKeyException,
InvalidAlgorithmParameterException,
IOException

Initializes the cipher with the provided key and reads the initialization vector from the input stream.

Parameters:

key - the key to be used for decryption

Returns:

true if the initialization was successful, false if it is unable to read the IV.

Throws:

InvalidKeyException - if the key is invalid

InvalidAlgorithmParameterException - if the algorithm parameters are invalid

IOException - if an I/O error occurs

read

public int read()
         throws IOException

Reads the next byte of data from the input stream.

Specified by:

read in class InputStream

Returns:

the next byte of data, or -1 if the end of the stream is reached

Throws:

IOException - if an I/O error occurs

read

public int read(byte[] bytes,
 int off,
 int len)
         throws IOException

Reads up to len bytes of data from the input stream into an array of bytes.

Overrides:

read in class InputStream

Parameters:

bytes - the buffer into which the data is read

off - the start offset in the buffer at which the data is written

len - the maximum number of bytes to read

Returns:

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached

Throws:

IOException - if an I/O error occurs

close

public void close()
           throws IOException

Closes the input stream.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class InputStream

Throws:

IOException - if an I/O error occurs