de.schlichtherle.io.archive.zip.raes
Class AbstractZipRaesDriver

java.lang.Object
  de.schlichtherle.io.archive.spi.AbstractArchiveDriver
      de.schlichtherle.io.archive.zip.ZipDriver
          de.schlichtherle.io.archive.zip.JarDriver
              de.schlichtherle.io.archive.zip.raes.AbstractZipRaesDriver

All Implemented Interfaces:

ArchiveDriver, Serializable

Direct Known Subclasses:

AbstractZip32RaesDriver, ParanoidZipRaesDriver, SafeZipRaesDriver, UnsafeZipRaesDriver

public abstract class AbstractZipRaesDriver
extends JarDriver

An abstract archive driver which builds RAES encrypted ZIP files and optionally authenticates the cipher data of the input archive files presented to it.

The constructor takes an optional authentication trigger parameter which can be used by subclasses to fine tune the authentication process. When omitted, the RAES Message Authentication Code (MAC) is always validated for the cipher text of input archive files.

Instances of this base class are immutable.

Since:

TrueZIP 6.0

Author:

Christian Schlichtherle

See Also:

Serialized Form

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

authenticationTrigger

private final long authenticationTrigger

AbstractZipRaesDriver

protected AbstractZipRaesDriver(Icon openIcon,
                                Icon closedIcon,
                                boolean preambled,
                                boolean postambled,
                                int level,
                                long authenticationTrigger)

Constructs a new abstract ZIP.RAES driver which uses the given byte size to trigger verification of the Message Authentication Code (MAC). Note that the given parameter only affects the authentication of the cipher text in input archives - the cipher key and file length are always authenticated with RAES.

Parameters:

authenticationTrigger - The trigger If set to a negative value, the MAC of input archive files gets never verified. If set to Long.MAX_VALUE, the MAC of input archive files gets always authenticated. Otherwise, the MAC of input archive files up to this size in bytes (including the overhead for the RAES wrapper data) only gets authenticated.

getAuthenticationTrigger

public final long getAuthenticationTrigger()

Returns the authentication trigger provided to the constructor. Note that this method is final for security reasons.

createInputArchive

public InputArchive createInputArchive(Archive archive,
                                       ReadOnlyFile rof)
                                throws IOException

This implementation calls getRaesParameters(de.schlichtherle.io.archive.Archive), with which it initializes a new RaesReadOnlyFile. Next, if the gross file length of the archive is smaller than or equal to the authentication trigger, the MAC authentication on the cipher text is performed. Finally, the RaesReadOnlyFile is passed on to the super class implementation.

Specified by:

createInputArchive in interface ArchiveDriver

Overrides:

createInputArchive in class ZipDriver

Parameters:

archive - The abstract archive representation which TrueZIP's internal ArchiveController is processing - never null.

rof - The ReadOnlyFile to read the actual archive contents from - never null. Hint: If you'ld prefer to have an InputStream, you could decorate this parameter with a ReadOnlyFileInputStream.

Returns:

A new input archive instance.

Throws:

TransientIOException - If calling this method for the same archive file again may finally succeed. This exception is associated with another IOException as its cause which is unwrapped and interpreted as below.

FileNotFoundException - If the input archive is inaccessible for any reason and you would like the package de.schlichtherle.io to mask the archive as a special file which cannot get read, written or deleted.

IOException - On any other I/O or data format related issue when reading the input archive and you would like the package de.schlichtherle.io to treat the archive like a regular file which may be read, written or deleted.

See Also:

InputArchive

createArchiveEntry

public ArchiveEntry createArchiveEntry(Archive archive,
                                       String entryName,
                                       ArchiveEntry template)
                                throws CharConversionException

Creates a new ZipEntry, enforcing that the data gets DEFLATED when written, even if copying data from a STORED source entry.

Specified by:

createArchiveEntry in interface ArchiveDriver

Overrides:

createArchiveEntry in class ZipDriver

Parameters:

archive - The abstract archive representation which TrueZIP's internal ArchiveController is processing - never null.

entryName - A valid archive entry name - never null.

template - If not null, then the newly created entry shall inherit as much attributes from this object as possible (with the exception of the name). This is typically used for archive copy operations. Note that there is no guarantee on the runtime type of this object; it may have been created by other drivers. It is safe to ignore the metaData property when copying entries.

Returns:

A new archive entry instance.

Throws:

CharConversionException - If name contains illegal characters.

See Also:

Requirements for Archive Entry Names

createOutputArchive

public OutputArchive createOutputArchive(Archive archive,
                                         OutputStream out,
                                         InputArchive source)
                                  throws IOException

This implementation calls getRaesParameters(de.schlichtherle.io.archive.Archive), with which it initializes a new RaesOutputStream, and finally passes the resulting stream to the super class implementation.

Specified by:

createOutputArchive in interface ArchiveDriver

Overrides:

createOutputArchive in class ZipDriver

Parameters:

archive - The abstract archive representation which TrueZIP's internal ArchiveController is processing - never null.

out - The OutputStream to write the archive entries to - never null.

source - The source InputArchive if archive is going to get updated. If not null, this is guaranteed to be a product of this driver's ArchiveDriver.createInputArchive(de.schlichtherle.io.archive.Archive, de.schlichtherle.io.rof.ReadOnlyFile) method. This may be used to copy some meta data which is specific to the type of archive this driver supports. For example, this could be used to copy the comment of a ZIP file.

Returns:

A new output archive instance.

Throws:

TransientIOException - If calling this method for the same archive file again may finally succeed. This exception is associated with another IOException as its cause which is unwrapped and interpreted as below.

FileNotFoundException - If the output archive is inaccessible for any reason.

IOException - On any other I/O or data format related issue when writing the output archive.

See Also:

OutputArchive

getRaesParameters

public RaesParameters getRaesParameters(Archive archive)

Returns the RaesParameters for the given canonical path name.

Parameters:

archive - The abstract archive representation which TrueZIP's internal ArchiveController is processing - never null.

Returns:

The RaesParameters to use for accessing the prospective RAES encrypted ZIP file.