anon.client.crypto

Class DefaultMixCipher

java.lang.Object

anon.client.crypto.DefaultMixCipher

All Implemented Interfaces:

IMixCipher

public class DefaultMixCipher
extends java.lang.Object
implements IMixCipher

This cipher is used for all intermittent mixes. It provides functionality to encrypt packets to be sent and decrypt received packets. It can also inform other methods of the expected amount of needed bytes as overhead.

Author:

Stefan Lieske

Constructor Summary

Constructors

Constructor and Description
DefaultMixCipher(MixParameters a_mixParameters, ISymCipher a_symCipher)

Method Summary

Modifier and Type	Method and Description
boolean	decrypt(byte[] a_packet) Decrypts the given byte array and saves the result in place.
byte[]	encrypt(byte[] a_packet, int a_virtualPacketLength, java.util.Vector a_sendCallbackHandlers) Encrypts a byte array using the underlying encryption algorithm for that mix.
int	getNextPacketEncryptionOverhead() Returns the overhead an encryption operation with this mix brings with it.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultMixCipher

public DefaultMixCipher(MixParameters a_mixParameters,
                        ISymCipher a_symCipher)

Parameters:

a_mixParameters -

a_symCipher -

Method Detail

encrypt

public byte[] encrypt(byte[] a_packet,
                      int a_virtualPacketLength,
                      java.util.Vector a_sendCallbackHandlers)

Description copied from interface: IMixCipher

Encrypts a byte array using the underlying encryption algorithm for that mix. The given callback handlers will be called, when the packet was successfully encrypted.

Specified by:

encrypt in interface IMixCipher

Parameters:

a_packet - The byte array to be encrypted.

a_virtualPacketLength - The minimal length of the resulting packet.

Returns:

A byte array containing the result of the encryption, possibly padded with random bytes until a_virtualPacketLength bytes long.

decrypt

public boolean decrypt(byte[] a_packet)

Description copied from interface: IMixCipher

Decrypts the given byte array and saves the result in place.

Specified by:

decrypt in interface IMixCipher

Returns:

true, if no errors occurred (including integrity checks)

getNextPacketEncryptionOverhead

public int getNextPacketEncryptionOverhead()

Description copied from interface: IMixCipher

Returns the overhead an encryption operation with this mix brings with it. This can change depending on if the message to be encrypted will be the first one (keys have to be sent, etc).

Specified by:

getNextPacketEncryptionOverhead in interface IMixCipher

Returns:

Number of bytes needed as overhead.