OpenCard  
 
OCF, the OpenCard Framework is a standard Java framework for working with Smart Cards.  
 

com.ibm.opencard.crypto
Class DES

java.lang.Object
  |
  +--com.ibm.opencard.crypto.DES
public final class DES
extends java.lang.Object

This class can be used to encrypt/decrypt blocks of 8 bytes using the standard Data Encryption Algorithm.

Version:
$Id: DES.java,v 1.1 1999/12/02 16:06:02 damke Exp $

Constructor Summary
DES()
          Constructs a new DES algorithm instance.
 
Method Summary
 void decrypt(byte[] block)
          Performs an in-place decryption of a 64-bit block.
 void encrypt(byte[] block)
          Performs an in-place encryption of a 64-bit block.
 void encryptSingle(byte[] block)
          Performs an in-place encryption of a 64-bit block, always using DES.
 void setkey(byte[] key)
          Sets the key to be used by the methods encrypt and decrypt.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DES

public DES()
Constructs a new DES algorithm instance. Each instance can be parameterized with exactly one key using setkey below. This has to be done before the first encrypt or decrypt operation.
This constructor prepares the space for a triple length 3DES key. Only parts of this space are used for double and single length keys.
See Also:
setkey(byte[])
Method Detail

setkey

public void setkey(byte[] key)
Sets the key to be used by the methods encrypt and decrypt.
Parameters:
key - The DES key to be used for encryption/decryption. The key can be 64, 128, or 192 bit in length. It will be used for single or triple DES operations, respectively. No parity checking is performed.

encrypt

public void encrypt(byte[] block)
Performs an in-place encryption of a 64-bit block. Depending on the length of the key previously set, DES or 3DES is used for encryption.
Parameters:
block - the 8 byte block to be encrypted. The block is encrypted in place, it's old content will be lost.

encryptSingle

public void encryptSingle(byte[] block)
Performs an in-place encryption of a 64-bit block, always using DES. Even if a double or triple length key has been previously set, this method performs a simple DES encryption, using the first 8 bytes of the current key. This is useful for some MAC computations.
Parameters:
block - the 8 byte block to be encrypted. The block is encrypted in place, it's old content will be lost.

decrypt

public void decrypt(byte[] block)
Performs an in-place decryption of a 64-bit block.
Parameters:
block - The block to be decrypted. The block is dedcrypted in place, so the old contents will be lost.