freenet.crypt

Class EncryptedRandomAccessBuffer

java.lang.Object

freenet.crypt.EncryptedRandomAccessBuffer

All Implemented Interfaces:

LockableRandomAccessBuffer, RandomAccessBuffer, java.io.Closeable, java.io.Serializable, java.lang.AutoCloseable

public final class EncryptedRandomAccessBuffer
extends java.lang.Object
implements LockableRandomAccessBuffer, java.io.Serializable

EncryptedRandomAccessBuffer is a encrypted RandomAccessBuffer implementation using a SkippingStreamCipher.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface freenet.support.api.LockableRandomAccessBuffer

LockableRandomAccessBuffer.RAFLock

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAGIC

Constructor Summary

Constructors

Constructor and Description
EncryptedRandomAccessBuffer(EncryptedRandomAccessBufferType type, LockableRandomAccessBuffer underlying, MasterSecret masterKey, boolean newFile) Creates an instance of EncryptedRandomAccessBuffer wrapping underlyingBuffer.

Method Summary

Modifier and Type	Method and Description
void	close()
static LockableRandomAccessBuffer	create(java.io.DataInputStream dis, FilenameGenerator fg, PersistentFileTracker persistentFileTracker, MasterSecret masterKey)
boolean	equals(java.lang.Object obj) Must reimplement equals().
void	free() Free the underlying resources.
int	hashCode() Must reimplement hashCode() if we change equals().
LockableRandomAccessBuffer.RAFLock	lockOpen() Keep the RAF open.
void	onResume(ClientContext context) Called on resuming, i.e.
void	pread(long fileOffset, byte[] buf, int bufOffset, int length) Reads the specified section of the underlying RAT and decrypts it.
void	pwrite(long fileOffset, byte[] buf, int bufOffset, int length) Encrypts the given data and writes it to the underlying RAT.
long	size()
void	storeTo(java.io.DataOutputStream dos) Write enough data to reconstruct the Bucket, or throw UnsupportedOperationException.

Methods inherited from class java.lang.Object

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

Field Detail

MAGIC

public static final int MAGIC

See Also:

Constant Field Values

Constructor Detail

EncryptedRandomAccessBuffer

public EncryptedRandomAccessBuffer(EncryptedRandomAccessBufferType type,
                                   LockableRandomAccessBuffer underlying,
                                   MasterSecret masterKey,
                                   boolean newFile)
                            throws java.io.IOException,
                                   java.security.GeneralSecurityException

Creates an instance of EncryptedRandomAccessBuffer wrapping underlyingBuffer. Keys for key encryption and MAC generation are derived from the MasterSecret. If this is a new ERAT then keys are generated and the footer is written to the end of the underlying RAT. Otherwise the footer is read from the underlying RAT.

Parameters:

type - The algorithms to be used for the ERAT

underlyingBuffer - The underlying RAT that will be storing the data. Must be larger than the footer size specified in type.

masterKey - The MasterSecret that will be used to derive various keys.

newFile - If true, treat it as a new file, and writer a header. If false, the ERAT must already have been initialised.

Throws:

java.io.IOException

java.security.GeneralSecurityException

Method Detail

size

public long size()

Specified by:

size in interface RandomAccessBuffer

pread

public void pread(long fileOffset,
                  byte[] buf,
                  int bufOffset,
                  int length)
           throws java.io.IOException

Reads the specified section of the underlying RAT and decrypts it. Decryption is thread-safe.

Specified by:

pread in interface RandomAccessBuffer

Parameters:

fileOffset - The offset within the file to read from.

buf - The buffer to write to.

bufOffset - The offset within the buffer to the first read byte.

length - The length of data to read.

Throws:

java.io.IOException - If we were unable to read the required number of bytes etc.

pwrite

public void pwrite(long fileOffset,
                   byte[] buf,
                   int bufOffset,
                   int length)
            throws java.io.IOException

Encrypts the given data and writes it to the underlying RAT. Encryption is thread-safe.

Specified by:

pwrite in interface RandomAccessBuffer

Throws:

java.io.IOException

close

public void close()

Specified by:

close in interface RandomAccessBuffer

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

free

public void free()

Description copied from interface: RandomAccessBuffer

Free the underlying resources. May do nothing in some implementations. You should make sure the object can be GC'ed as well.

Specified by:

free in interface RandomAccessBuffer

lockOpen

public LockableRandomAccessBuffer.RAFLock lockOpen()
                                            throws java.io.IOException

Description copied from interface: LockableRandomAccessBuffer

Keep the RAF open. Does not prevent others from writing to it. Will block until a slot is available if necessary. Hence can deadlock.

Specified by:

lockOpen in interface LockableRandomAccessBuffer

Throws:

java.io.IOException

onResume

public void onResume(ClientContext context)
              throws ResumeFailedException

Description copied from interface: LockableRandomAccessBuffer

Called on resuming, i.e. after serialization. Use to e.g. register with the list of temporary files.

Specified by:

onResume in interface LockableRandomAccessBuffer

Throws:

ResumeFailedException

storeTo

public void storeTo(java.io.DataOutputStream dos)
             throws java.io.IOException

Description copied from interface: LockableRandomAccessBuffer

Write enough data to reconstruct the Bucket, or throw UnsupportedOperationException. Used for recovering in emergencies, should be versioned if necessary. To make this work, write a fixed, unique integer magic value for the class, and add a clause to BucketTools.restoreRAFFrom().

Specified by:

storeTo in interface LockableRandomAccessBuffer

Throws:

java.io.IOException

create

public static LockableRandomAccessBuffer create(java.io.DataInputStream dis,
                                                FilenameGenerator fg,
                                                PersistentFileTracker persistentFileTracker,
                                                MasterSecret masterKey)
                                         throws java.io.IOException,
                                                StorageFormatException,
                                                ResumeFailedException

Throws:

java.io.IOException

StorageFormatException

ResumeFailedException

hashCode

public int hashCode()

Description copied from interface: LockableRandomAccessBuffer

Must reimplement hashCode() if we change equals().

Specified by:

hashCode in interface LockableRandomAccessBuffer

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Description copied from interface: LockableRandomAccessBuffer

Must reimplement equals(). Sometimes we will need to compare two RAFs to see if they represent the same stored object, notably during resuming a splitfile insert.

Specified by:

equals in interface LockableRandomAccessBuffer

Overrides:

equals in class java.lang.Object