com.sshtools.ssh.components

Class SshCipher

java.lang.Object

com.sshtools.ssh.components.SshCipher

Direct Known Subclasses:

AbstractJCECipher, NoneCipher

public abstract class SshCipher
extends Object

Base class for all SSH protocol ciphers. The cipher itself has 2 modes, encryption or decrpytion. The same method is used to transporm the data depending upon the mode.

Author:

Lee David Painter

Field Summary

Fields

Modifier and Type	Field and Description
static int	DECRYPT_MODE Decryption mode.
static int	ENCRYPT_MODE Encryption mode.

Constructor Summary

Constructors

Constructor and Description
SshCipher(String algorithm)

Method Summary

Modifier and Type	Method and Description
String	getAlgorithm()
abstract int	getBlockSize() Get the cipher block size.
abstract int	getKeyLength() Return the key length required
abstract void	init(int mode, byte[] iv, byte[] keydata) Initialize the cipher with up to 40 bytes of iv and key data.
void	transform(byte[] data) Transform the byte array according to the cipher mode.
abstract void	transform(byte[] src, int start, byte[] dest, int offset, int len) Transform the byte array according to the cipher mode; it is legal for the source and destination arrays to reference the same physical array so care should be taken in the transformation process to safeguard this rule.

Methods inherited from class java.lang.Object

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

Field Detail

ENCRYPT_MODE

public static final int ENCRYPT_MODE

Encryption mode.

See Also:

Constant Field Values

DECRYPT_MODE

public static final int DECRYPT_MODE

Decryption mode.

See Also:

Constant Field Values

Constructor Detail

SshCipher

public SshCipher(String algorithm)

Method Detail

getAlgorithm

public String getAlgorithm()

getBlockSize

public abstract int getBlockSize()

Get the cipher block size.

Returns:

the block size in bytes.

getKeyLength

public abstract int getKeyLength()

Return the key length required

Returns:

init

public abstract void init(int mode,
                          byte[] iv,
                          byte[] keydata)
                   throws IOException

Initialize the cipher with up to 40 bytes of iv and key data. Each implementation should take as much data from the initialization as it needs ignoring any data that it does not require.

Parameters:

mode - the mode to operate

iv - the initiaization vector

keydata - the key data

Throws:

IOException

transform

public void transform(byte[] data)
               throws IOException

Transform the byte array according to the cipher mode.

Parameters:

data -

Throws:

IOException

transform

public abstract void transform(byte[] src,
                               int start,
                               byte[] dest,
                               int offset,
                               int len)
                        throws IOException

Transform the byte array according to the cipher mode; it is legal for the source and destination arrays to reference the same physical array so care should be taken in the transformation process to safeguard this rule.

Parameters:

src -

start -

dest -

offset -

len -

Throws:

IOException