2 // KeyedHashAlgorithm.cs: Handles keyed hash and MAC classes.
5 // Sebastien Pouliot (sebastien@ximian.com)
7 // (C) 2002 Motus Technologies Inc. (http://www.motus.com)
8 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
10 // Permission is hereby granted, free of charge, to any person obtaining
11 // a copy of this software and associated documentation files (the
12 // "Software"), to deal in the Software without restriction, including
13 // without limitation the rights to use, copy, modify, merge, publish,
14 // distribute, sublicense, and/or sell copies of the Software, and to
15 // permit persons to whom the Software is furnished to do so, subject to
16 // the following conditions:
18 // The above copyright notice and this permission notice shall be
19 // included in all copies or substantial portions of the Software.
21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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30 using System.Globalization;
31 using System.Runtime.InteropServices;
33 namespace System.Security.Cryptography {
36 public abstract class KeyedHashAlgorithm : HashAlgorithm {
38 protected byte[] KeyValue;
40 protected KeyedHashAlgorithm () : base ()
42 // create a random 64 bits key
45 ~KeyedHashAlgorithm ()
50 public virtual byte[] Key {
52 return (byte[]) KeyValue.Clone ();
55 // can't change the key during a hashing ops
57 throw new CryptographicException (
58 Locale.GetText ("Key can't be changed at this state."));
60 // zeroize current key material for security
63 KeyValue = (byte[]) value.Clone ();
67 protected override void Dispose (bool disposing)
69 // zeroize key material for security
71 // dispose managed resources
73 // dispose unmanaged resources
75 // calling base class HashAlgorithm
76 base.Dispose (disposing);
79 private void ZeroizeKey()
82 Array.Clear (KeyValue, 0, KeyValue.Length);
85 public static new KeyedHashAlgorithm Create ()
87 return Create ("System.Security.Cryptography.KeyedHashAlgorithm");
90 public static new KeyedHashAlgorithm Create (string algName)
92 return (KeyedHashAlgorithm) CryptoConfig.CreateFromName (algName);