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
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30 using System.Globalization;
31 using System.Runtime.InteropServices;
33 namespace System.Security.Cryptography {
38 public abstract class KeyedHashAlgorithm : HashAlgorithm {
40 protected byte[] KeyValue;
42 protected KeyedHashAlgorithm () : base ()
44 // create a random 64 bits key
47 ~KeyedHashAlgorithm ()
52 public virtual byte[] Key {
54 return (byte[]) KeyValue.Clone ();
57 // can't change the key during a hashing ops
59 throw new CryptographicException (
60 Locale.GetText ("Key can't be changed at this state."));
62 // zeroize current key material for security
65 KeyValue = (byte[]) value.Clone ();
69 protected override void Dispose (bool disposing)
71 // zeroize key material for security
73 // dispose managed resources
75 // dispose unmanaged resources
77 // calling base class HashAlgorithm
78 base.Dispose (disposing);
81 private void ZeroizeKey()
84 Array.Clear (KeyValue, 0, KeyValue.Length);
87 public static new KeyedHashAlgorithm Create ()
89 return Create ("System.Security.Cryptography.KeyedHashAlgorithm");
92 public static new KeyedHashAlgorithm Create (string algName)
94 return (KeyedHashAlgorithm) CryptoConfig.CreateFromName (algName);