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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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package javax.crypto.spec;
import java.security.InvalidKeyException;
/**
* This class specifies a DES-EDE ("triple-DES") key.
*
* @author Jan Luehe
*
* @since 1.4
*/
public class DESedeKeySpec implements java.security.spec.KeySpec {
/**
* The constant which defines the length of a DESede key in bytes.
*/
public static final int DES_EDE_KEY_LEN = 24;
private byte[] key;
/**
* Creates a DESedeKeySpec object using the first 24 bytes in
* <code>key</code> as the key material for the DES-EDE key.
*
* <p> The bytes that constitute the DES-EDE key are those between
* <code>key[0]</code> and <code>key[23]</code> inclusive
*
* @param key the buffer with the DES-EDE key material. The first
* 24 bytes of the buffer are copied to protect against subsequent
* modification.
*
* @exception NullPointerException if <code>key</code> is null.
* @exception InvalidKeyException if the given key material is shorter
* than 24 bytes.
*/
public DESedeKeySpec(byte[] key) throws InvalidKeyException {
this(key, 0);
}
/**
* Creates a DESedeKeySpec object using the first 24 bytes in
* <code>key</code>, beginning at <code>offset</code> inclusive,
* as the key material for the DES-EDE key.
*
* <p> The bytes that constitute the DES-EDE key are those between
* <code>key[offset]</code> and <code>key[offset+23]</code> inclusive.
*
* @param key the buffer with the DES-EDE key material. The first
* 24 bytes of the buffer beginning at <code>offset</code> inclusive
* are copied to protect against subsequent modification.
* @param offset the offset in <code>key</code>, where the DES-EDE key
* material starts.
*
* @exception NullPointerException if <code>key</code> is null.
* @exception InvalidKeyException if the given key material, starting at
* <code>offset</code> inclusive, is shorter than 24 bytes
*/
public DESedeKeySpec(byte[] key, int offset) throws InvalidKeyException {
if (key.length - offset < 24) {
throw new InvalidKeyException("Wrong key size");
}
this.key = new byte[24];
System.arraycopy(key, offset, this.key, 0, 24);
}
/**
* Returns the DES-EDE key.
*
* @return the DES-EDE key. Returns a new array
* each time this method is called.
*/
public byte[] getKey() {
return (byte[])this.key.clone();
}
/**
* Checks if the given DES-EDE key, starting at <code>offset</code>
* inclusive, is parity-adjusted.
*
* @param key a byte array which holds the key value
* @param offset the offset into the byte array
* @return true if the given DES-EDE key is parity-adjusted, false
* otherwise
*
* @exception NullPointerException if <code>key</code> is null.
* @exception InvalidKeyException if the given key material, starting at
* <code>offset</code> inclusive, is shorter than 24 bytes
*/
public static boolean isParityAdjusted(byte[] key, int offset)
throws InvalidKeyException {
if (key.length - offset < 24) {
throw new InvalidKeyException("Wrong key size");
}
if (DESKeySpec.isParityAdjusted(key, offset) == false
|| DESKeySpec.isParityAdjusted(key, offset + 8) == false
|| DESKeySpec.isParityAdjusted(key, offset + 16) == false) {
return false;
}
return true;
}
}