Constructor Detail

• CipherReadOnlyFile

  @CreatesObligation
  protected CipherReadOnlyFile(@Nullable@WillCloseWhenClosed
                                      ReadOnlyFile rof)

  Creates a read only file for transparent random read access to an encrypted file. The client must call init(SeekableBlockCipher, long, long) before it can actually read anything!

  Parameters:

  rof - A read-only file. This may be null, but must be properly initialized before a call to init(de.schlichtherle.truezip.crypto.SeekableBlockCipher, long, long).

Method Detail

• close

  public void close()
             throws IOException

  Closes this read only file and releases any resources associated with it. This method invalidates the state of this object, causing any subsequent calls to a public method to fail with an IOException.

  Specified by:

  close in interface ReadOnlyFile

  Specified by:

  close in interface Closeable

  Specified by:

  close in interface AutoCloseable

  Overrides:

  close in class DecoratingReadOnlyFile

  Throws:

  IOException - If an I/O error occurs.

• computeMac

  protected byte[] computeMac(Mac mac)
                       throws IOException

  Returns the authentication code of the encrypted data in this cipher read-only file using the given Message Authentication Code (MAC) object. It is safe to call this method multiple times to detect if the file has been tampered with meanwhile.

  Parameters:

  mac - a properly initialized MAC object.

  Returns:

  A byte array with the authentication code.

  Throws:

  IOException - on any I/O error.

• getFilePointer

  public long getFilePointer()
                      throws IOException

  Specified by:

  getFilePointer in interface ReadOnlyFile

  Overrides:

  getFilePointer in class DecoratingReadOnlyFile

  Throws:

  IOException

• init

  protected final void init(SeekableBlockCipher cipher,
          long start,
          long length)
                     throws IOException

  Initializes this cipher read only file - must be called before first read access!

  Parameters:

  cipher - the seekable block cipher.

  start - the start offset of the encrypted data in this file.

  length - the length of the encrypted data in this file.

  Throws:

  IOException - If this read only file has already been closed. This exception is not recoverable.

  IllegalStateException - if DecoratingReadOnlyFile.delegate is null or if this object has already been initialized.

  IllegalArgumentException - if cipher is null or if start or length are less than zero.

• length

  public long length()
              throws IOException

  Specified by:

  length in interface ReadOnlyFile

  Overrides:

  length in class DecoratingReadOnlyFile

  Throws:

  IOException

• read

  public int read()
           throws IOException

  Specified by:

  read in interface ReadOnlyFile

  Overrides:

  read in class DecoratingReadOnlyFile

  Throws:

  IOException

• read

  public int read(byte[] dst,
         int offset,
         int remaining)
           throws IOException

  Specified by:

  read in interface ReadOnlyFile

  Overrides:

  read in class DecoratingReadOnlyFile

  Throws:

  IOException

• seek

  public void seek(long pos)
            throws IOException

  Specified by:

  seek in interface ReadOnlyFile

  Overrides:

  seek in class DecoratingReadOnlyFile

  Throws:

  IOException