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//
// System.Security.Cryptography.DES
//
// Author:
// Sergey Chaban (serge@wildwestsoftware.com)
// Sebastien Pouliot <sebastien@ximian.com>
//
// Portions (C) 2002 Motus Technologies Inc. (http://www.motus.com)
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.Globalization;
using System.Security.Cryptography;
// References:
// a. FIPS PUB 46-3: Data Encryption Standard
// http://csrc.nist.gov/publications/fips/fips46-3/fips46-3.pdf
namespace System.Security.Cryptography {
public abstract class DES : SymmetricAlgorithm {
const int blockSizeByte = 8;
public DES ()
{
KeySizeValue = 64;
BlockSizeValue = 64;
FeedbackSizeValue = 8;
LegalKeySizesValue = new KeySizes[1];
LegalKeySizesValue[0] = new KeySizes(64, 64, 0);
LegalBlockSizesValue = new KeySizes[1];
LegalBlockSizesValue[0] = new KeySizes(64, 64, 0);
}
public static new DES Create ()
{
return Create ("System.Security.Cryptography.DES");
}
public static new DES Create (string algo)
{
return (DES) CryptoConfig.CreateFromName (algo);
}
internal static ulong PackKey (byte[] key)
{
byte[] paritySetKey = new byte [blockSizeByte];
// adapted from bouncycastle - see bouncycastle.txt
for (int i=0; i < key.Length; i++) {
byte b = key [i];
paritySetKey [i] = (byte)((b & 0xfe) |
((((b >> 1) ^ (b >> 2) ^ (b >> 3) ^ (b >> 4) ^
(b >> 5) ^ (b >> 6) ^ (b >> 7)) ^ 0x01) & 0x01));
}
ulong res = 0;
for (int i = 0, sh = 8*blockSizeByte; (sh = sh - 8) >= 0; i++) {
res |= (ulong) paritySetKey [i] << sh;
}
Array.Clear (paritySetKey, 0, paritySetKey.Length);
return res;
}
// Ek(Ek(m)) = m
internal static readonly ulong[] weakKeys = {
0x0101010101010101, /* 0000000 0000000 */
0xFEFEFEFEFEFEFEFE, /* FFFFFFF FFFFFFF */
0x1F1F1F1F0E0E0E0E, /* 0000000 FFFFFFF */
0xE0E0E0E0F1F1F1F1 /* FFFFFFF 0000000 */
};
// Ek1(Ek2(m)) = m
internal static readonly ulong[] semiweakKeys = {
0x01FE01FE01FE01FE, 0xFE01FE01FE01FE01,
0x1FE01FE00EF10EF1, 0xE01FE01FF10EF10E,
0x01E001E001F101F1, 0xE001E001F101F101,
0x1FFE1FFE0EFE0EFE, 0xFE1FFE1FFE0EFE0E,
0x011F011F010E010E, 0x1F011F010E010E01,
0xE0FEE0FEF1FEF1FE, 0xFEE0FEE0FEF1FEF1
};
public static bool IsWeakKey (byte[] rgbKey)
{
if (rgbKey.Length != blockSizeByte)
throw new CryptographicException (Locale.GetText ("Wrong Key Length"));
ulong lk = PackKey (rgbKey);
foreach (ulong wk in weakKeys) {
if (lk == wk)
return true;
}
return false;
}
public static bool IsSemiWeakKey (byte[] rgbKey)
{
if (rgbKey.Length != blockSizeByte)
throw new CryptographicException (Locale.GetText ("Wrong Key Length"));
ulong lk = PackKey (rgbKey);
foreach (ulong swk in semiweakKeys) {
if (lk == swk)
return true;
}
return false;
}
public override byte[] Key {
get {
if (KeyValue == null) {
// GenerateKey is responsible to return a valid key
// e.g. no weak or semi-weak keys
GenerateKey ();
}
return (byte[]) KeyValue.Clone ();
}
set {
if (value == null)
throw new ArgumentNullException ("Key");
if (value.Length != blockSizeByte)
throw new ArgumentException (Locale.GetText ("Wrong Key Length"));
if (IsWeakKey (value))
throw new CryptographicException (Locale.GetText ("Weak Key"));
if (IsSemiWeakKey (value))
throw new CryptographicException (Locale.GetText ("Semi Weak Key"));
KeyValue = (byte[]) value.Clone ();
}
}
}
}
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