package org.bouncycastle.crypto.params;
public class DESedeParameters
extends DESParameters
{
/*
* DES-EDE Key length in bytes.
*/
static public final int DES_EDE_KEY_LENGTH = 24;
public DESedeParameters(
byte[] key)
{
super(key);
if (isWeakKey(key, 0, key.length))
{
throw new IllegalArgumentException("attempt to create weak DESede key");
}
}
/**
* return true if the passed in key is a DES-EDE weak key.
*
* @param key bytes making up the key
* @param offset offset into the byte array the key starts at
* @param length number of bytes making up the key
*/
public static boolean isWeakKey(
byte[] key,
int offset,
int length)
{
for (int i = offset; i < length; i += DES_KEY_LENGTH)
{
if (DESParameters.isWeakKey(key, i))
{
return true;
}
}
return false;
}
/**
* return true if the passed in key is a DES-EDE weak key.
*
* @param key bytes making up the key
* @param offset offset into the byte array the key starts at
*/
public static boolean isWeakKey(
byte[] key,
int offset)
{
return isWeakKey(key, offset, key.length - offset);
}
/**
* return true if the passed in key is a real 2/3 part DES-EDE key.
*
* @param key bytes making up the key
* @param offset offset into the byte array the key starts at
*/
public static boolean isRealEDEKey(byte[] key, int offset)
{
return key.length == 16 ? isReal2Key(key, offset) : isReal3Key(key, offset);
}
/**
* return true if the passed in key is a real 2 part DES-EDE key.
*
* @param key bytes making up the key
* @param offset offset into the byte array the key starts at
*/
public static boolean isReal2Key(byte[] key, int offset)
{
boolean isValid = false;
for (int i = offset; i != offset + 8; i++)
{
if (key[i] != key[i + 8])
{
isValid = true;
}
}
return isValid;
}
/**
* return true if the passed in key is a real 3 part DES-EDE key.
*
* @param key bytes making up the key
* @param offset offset into the byte array the key starts at
*/
public static boolean isReal3Key(byte[] key, int offset)
{
boolean diff12 = false, diff13 = false, diff23 = false;
for (int i = offset; i != offset + 8; i++)
{
diff12 |= (key[i] != key[i + 8]);
diff13 |= (key[i] != key[i + 16]);
diff23 |= (key[i + 8] != key[i + 16]);
}
return diff12 && diff13 && diff23;
}
}