gnu.crypto.mode
public interface IMode extends IBlockCipher
The basic visible methods of any block cipher mode.
Block ciphers encrypt plaintext in fixed size n-bit blocks. For messages larger than n bits, the simplest approach is to segment the message into n-bit blocks and process (encrypt and/or decrypt) each one separately (Electronic Codebook or ECB mode). But this approach has disadvantages in most applications. The block cipher modes of operations are one way of working around those disadvantages.
A Mode always employs an underlying block cipher for processing its input. For all intents and purposes, a Mode appears to behave as any other block cipher with the following differences:
Possible additional initialisation values for an instance of that type are:
reset()
is invoked on the
instance.Version: $Revision: 1.5 $
Field Summary | |
---|---|
int | DECRYPTION Constant indicating the instance is being used for decryption. |
int | ENCRYPTION Constant indicating the instance is being used for encryption. |
String | IV Property name of the initialisation vector to use, if required, with this instance. |
String | MODE_BLOCK_SIZE Property name of the block size in which to operate this mode. |
String | STATE Property name of the state in which to operate this mode. |
Method Summary | |
---|---|
void | update(byte[] in, int inOffset, byte[] out, int outOffset) A convenience method. |
Constant indicating the instance is being used for decryption.
Constant indicating the instance is being used for encryption.
Property name of the initialisation vector to use, if required, with this instance. The value associated with this property name is taken to be a byte array. If the concrete instance needs such a parameter, and it has not been specified as part of the initialissation parameters, an all-zero byte array of the appropriate size shall be used.
Property name of the block size in which to operate this mode. The value associated with this property name is taken to be an Integer. If it is not specified, the value of the block size of the underlying block cipher, used to construct the mode instance, shall be used.
Property name of the state in which to operate this mode. The value
associated to this property name is taken to be an Integer which
value is either ENCRYPTION
or DECRYPTION
.
A convenience method. Effectively invokes the encryptBlock()
or decryptBlock()
method depending on the operational state
of the instance.
Parameters: in the plaintext. inOffset index of in
from which to start considering
data. out the ciphertext. outOffset index of out
from which to store result.
Throws: IllegalStateException if the instance is not initialised.